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  • Huracanes y calentamiento global ¿Hay conexión? « RealClimate
    will not get involved in any political or economic implications of the science There is a lot of work covering the economics of climate change as well as adapation and mitigation You don t seem to be covering these issues Economics is a science it s certainly rather complex as the misunderstandings of said science evident in comments 7 and 10 show Without going into excruciating detail economists are not saying that hurricanes are making us better off or that there d be no costs attributable to climate change if GDP in the year 2100 were 99 composed of reconstructing housing after hurricanes 14 Steve Bloom says 2 Sep 2005 at 8 44 PM Re 11 The warm water does seem to be important Remember that it s a relatively late season development so earlier hurricanes didn t get the full impact Also Katrina s path and speed resulted in it having what looks to be an unusual amount of dwell time in the upper Gulf So we should be able to see an obvious effect on other hurricanes that spend much time in that area Probably it s a good thing that hurricanes occurring much later than now tend to track into the Atlantic East Coast 15 Stephen Berg says 2 Sep 2005 at 9 06 PM Re 12 I do not think SSTs can be overemphasised since it is from the seas that hurricanes obtain their energy If SSTs were even an extra tenth or even hundredth of a degree warmer it would increase the energy of the storm enough to increase the number of people killed and the damage done to property by the storm Sure wind shear and other factors play a part in the setup of these storms but these other factors do not contribute much to the overall energy of the storm at least not nearly to the extent that SSTs contribute 16 Steve Latham says 2 Sep 2005 at 10 20 PM Dear Heiko 14 at this time Thanks for not going into excruciating detail but I m curious about what you are suggesting I don t understand or Lynn for that matter You posted statements that economics doesn t account very well or objectively for various kinds of costs e g damage to coral reefs harm to tropical or poor countries etc I agreed and posted quotes from some real working economists indicating that GDP their usual metric is positively stimulated by disasters My comment was that those changes in GDP don t correlate positively with changes in my quality of life What am I missing 17 dusty says 2 Sep 2005 at 10 25 PM To me its simple and scary More heat equals more powerful storms In my heart that little voice of truth says that more of this is to come I have to note that I stay up late worrying for our future The sad truth is we cannot really know the effects of higher sea surface temperatures other than to have proof that they provide a nice comfy atmosphere for more destructive storms As a somewhat educated layperson trying to raise awareness in my own little corner of the net im starting to find that at least some denizens of this planet are waking up to this We have so far to go though Thank you for running this blog God Bless And keep it up 18 Eli Rabett says 3 Sep 2005 at 12 55 AM The current Landsea Trenberth Emanuel discussion has been parsed by many to mean that Landsea claims that the number of hurricanes is constant and Trenberth is claiming that their intensity should increase as global warming heats the ocean surface Emanuel appears to have constructed a figure of merit that confirms both sides of the furious agreement However there is a simple logical fallacy in this reconciliation If we are talking about hurricanes and not just tropical disturbances a certain proportion of tropical storms will move up to hurricane status if Trenberth is right and that indeed is what Emanuel has shown Therefore at some point either someone is eliding tropical storms into hurricanes or someone else is making a false statement Response True and one must be careful to say whether one refers to hurricanes with windspeed above a certain threshold or just tropical cyclones rasmus 19 wayne davidson says 3 Sep 2005 at 1 38 AM Katrina s origins were so close to inhabited islands that it is likely an excellent hurricane to analyze The relation with heat and destruction seems clear with Andrew at the beginning of the then warmest year in history 1998 and Katrina at now what may surely be the warmest year in history for the Northern Hemisphere Furiously destructive Hurricanes are not the only indicator of AGW in context of those Hurricanes cycles in the past or rather in contrast with past high intensity hurricane seasons we now experience all time high temperatures raging everywhere in the world 1 meter a day rainfalls severe droughts on 4 distinct continents many glaciers going or gone everywhere and a good chunk of the Arctic Ocean permanent ice melted Those just claiming that Katrina is part of a normal cycle must somehow show that all these other distant but simultaneous temperature related changes have nothing to do with the Gulf of Mexico or show that all other world wide warming cycles occurred at the same time as preceding Atlantic Multidecadal Oscillations I doubt that normal cycle hurricane theorists can demonstrate that glaciers have melted to the extent that they have today replenish themselves again only to achieve today s all time low ice volumes The problem is Global the symptoms are local and they vary according to highly individualized environments however the common thread is Global Warming 20 joseph says 3 Sep 2005 at 2 14 AM Excuse me if I m being simple minded here but before we apply all of this incredibly complicated speculatory science to analyzing Katrina doesn t it make sense to compare it with the historical record Any simple glance at Hurricane records show that this is not the first time in history such hurricanes have occured 1931 was an incredibly destructive year In 2000 there was not a single land fall There is little solid historical evidence that hurricanes are increasing in number or destructiveness This seems more telling than uncertain infinitely complex computer models I just believe we can t let speculative science get in the way of more simple logic If hurricanes like this have hit with some regularity in the past which they have is it not jumping the gun a little to slap down a global warming tag on it I am not denying global warming in anyway just I think it is best to always check speculation with a little more sober look into fact Response Have a look at Fig 2 of the post this is the sober data you want not speculation stefan 21 Heiko Gerhauser says 3 Sep 2005 at 7 36 AM Steve economists would not regard the quarterly changes in GDP discussed in the article as the most appropriate metric for judging the economic damage from a hurricane in particular because GDP is a proxy for production rather than assets Economists do consider quality of life issues though there is no consensus on how best to deal with them in cost benefit analyses 22 David Ball says 3 Sep 2005 at 10 13 AM As a severe weather meteorologist I can t stress enough how important articles like this are Whenever extreme weather occurs the public inevitably tries on some level to put the event into some type of global context So a tornado touches down devastating a community or a hurricane like Katrina does the unthinkable and the inevitable questions come up is this El Nino Is this global warming Is this normal All of these questions are valid and merit discussion but the problem is that there is simply no way to answer them short of a blithe yes these things are normal and as tragic as they are they may happen again and yes there might be an impact from global warming or something else but I can t say exactly what they are Having the folks at RealClimate present the current state of the science and basically state what we in the meteorology community already find on a day to day basis is very gratifying Keep up the good work 23 Lynn Vincentnathan says 3 Sep 2005 at 11 30 AM RE 21 Okay let s take the Galveston cat 4 hurricane of 1900 Maybe some scientist could do a rough estimate of how much wmore intense it would have been with GW the added increase in SST due to GW though there might not be enough info on that hurricane Another question If hurricanes are to increase in intensity then at some future point will we have to add another number like category 6 or are there constraints that make it beyond physical possibilities 24 Pat Neuman says 3 Sep 2005 at 11 37 AM Regarding 11 Mr Pielke the referenced pdf shows an article in press Dec 2005 on Hurricanes and Global Warming Bulletin of the American Meteorological Society The authors shown in the article include yourself the NOAA professionals listed below and two others with the Tropical Prediction Center in Miami FL NOAA professionals Christopher Landsea Research Meteorologist NOAA AOML Hurricane Research Division Miami Florida Jim Laver Director Climate Prediction Center NOAA National Weather Service National Centers for Environmental Predicion Camp Springs Maryland Questions Are the statements in the pdf article Accepted 27 August 2005 in agreement with NOAA s policy on climate change Did Mr John Mahoney of NOAA give his approval to the content of the article Response One would hope that science articles would be judged on quality rather than conformity with policy Does NOAA even have a policy on climate change William 25 Heiko Gerhauser says 3 Sep 2005 at 12 47 PM Re 23 What could also be done would be too look at all hurricanes making landfall in the 20th century and then modelling the effect of 21st century sea water temperatures on them In the 20th century 3 category 5 hurricanes made landfall in the United States tripling that would mean 9 cat 5 hurricanes but that should be the risk for year 2100 SST s So maybe 6 7 cat 5 hurricanes in a business as usual scenario for the 21st century and with concerted climate action over most of the 21st century that could be reduced I guess by 1 landfalling cat 5 hurricane which would be avoided likely sometime between 2050 and 2100 and of course it would be nice to have that firmed up a bit maybe including a glancing look at the near term effects of climate action to quantify how close to negligible they d be The 2100 cut off is somewhat arbitrary more cat 5 hurricanes could be avoided in the 22nd century but also most of the climate action for that could occur late It s the big lag times in energy and climate systems which I think make consideration of impacts 50 100 years out particularly appropriate 26 Mark Trexler says 3 Sep 2005 at 1 12 PM A great article Stefan comments at one point What I am trying to say a warm climate is no worse than a cold climate But large and rapid change is the problem because new things happen that we and our infrastructure are not adapted to This is a pivotal point We frequently hear that it used to be warmer and the dinosaurs liked it just fine That s great but we now have 6 billion humans hanging on to the planet many pretty marginally It s not that a warmed planet will be inferior to today s planet but what happens to those 6 billion people during the transition 27 PHEaston says 3 Sep 2005 at 4 29 PM What is missing Your article concludes with the very strong statements The current evidence strongly suggests that a hurricanes tend to become more destructive as ocean temperatures rise and b an unchecked rise in greenhouse gas concentrations will very likely increase ocean temperatures further ultimately overwhelming any natural oscillations However after carefully re reading the article I can t see where this evidence comes from The nearest to evidence for a might be your Figures 1 and 2 Figure 1 indicates that more CO2 will lead to an increase in hurricane intensity However this result is derived from a predictive computer model and not evidence In any case you state this SUGGESTS that hurricanes MAY indeed become more destructive which clearly does not represent strong evidence Figure 2 shows an apparent correlation between a power dissipation index PDI and North Atlantic SST There is no explanation of what PDI is other than that it is LIKELY a better measure of the destructive potential of the storms than previously used measures The term likely can not sensibly be transposed to strong evidence From here we are led to the statement as tropical SSTs have increased in past decades so has the intrinsic destructive potential of hurricanes A more convincing conclusion from the graph is that as tropical SSTs have increased in past decades so has the PDI It seems the reader is meant to have faith that an increase in PDI represents an increase in destructive potential as no justification for this connection is presented In relation to the findings of Emmanuel 2005 you state caution is always warranted with very new scientific results until they have been thoroughly discussed by the community and either supported or challenged by further analyses This is a sensible statement but one that does not appear to correlate with your strong final conclusions Conclusion b bears no relation to evidence presented in your article and appears to be based either on opinion or on the results of other studies not referred to or referenced here Don t assume I aim to discredit your conclusions As a scientist I just don t see how they derive from the information provided in the article Response Concerning a there is a lot of evidence for hurricanes tending to become more destructive with increasing SST E g the fact that they arise only over warm SST 27 ºC to begin with Also if you follow the hurricane forecasts of the National Hurricane Center on the web you will see that SST is one of the key factors routinely used with every hurricane to forecast whether it will strengthen or weaken E g on Friday 26 August the 11 30 a m Katrina discussion read STEADY INTENSIFICATION TO NEAR CATEGORY FOUR STRENGTH BY 72 HOURS APPEARS TO BE IN ORDER GIVEN THE VERY WARM GULF WATERS BENEATH THE HURRICANE As you know unfortunately this forecast was correct Concerning the power dissipation index this is the wind speed cubed integrated over the surface area covered by the hurricane and over time It is simply an integral measure of the strength of the hurricane You could have also used the wind speed But to a physicist power dissipation is a more sensible measure partly because there is conservation laws for energy not for wind speed and partly because any damage caused to structures is more closely related to the power transferred to them rather than to wind speed itself The evidence for conclusion b that global warming will make SST warmer was indeed not discussed in this post but in many others on our site This is simply the standard evidence for rising CO2 concentration leading to global warming You could turn to the IPCC reports if you are interested in this evidence or e g to one of my own articles which summarises the evidence briefly at the outset stefan 28 Lynn Vincentnathan says 3 Sep 2005 at 4 43 PM An engineer Dan on another blog http www marklynas org wind message 1930 html has put this forth I edited it for brevity I think I did read about the thermohaline circulation slowing down somewhat Could you RealClimate scientists comment on Dan s points GW affects the Gulf area in hurricane formation on 2 grounds First there may be local heating and second higher latitude heating may help augment the decadal cycles being cited as the reason for the increased frequency Both GW related aspects increase heat retention by the Gulf and therefore hurricane intensity First the Gulf of Mexico is very shallow with 38 percent of the ocean less than 20 meters deep Because of this shallow depth the earth s heat imbalance can raise the temperature of this area faster and distribute that heat throughout the region I calculated that the earth s heat imbalance of 0 85 W m2 can raise the temperature of the first meter of ocean by a degree in about 2 months if all the heat was totally contained in that first meter Since 20 meters is not a great depth and if we assume the heat imbalance of 0 85 W m2 went to heat just that shallow area then it would take 2 years for the heat imbalance to raise the shallow ocean area an extra degree The heat form the Gulf of Mexico is distributed world wide and even warms Europe We are talking about the heat imbalance and if the long term average flow rate of the current remained the same then we would still have an imbalance with more heat being concentrated in the Gulf waters due to GW Second weather events concerning the decadal cycles which place us in a hurricane season I believe are due in part to GW if the thermohaline circulation is being reduced which would slow the Gulf Stream down flow rate out and therefore prevent the escape of heat from the Gulf region Increases in temperatures of the higher latitudes would also decrease density because warmer water is less dense Since both ice melt and higher temperatures are happening then density will be lower and this slows the Gulf Stream and adds to the decadal weather event which keeps more heat in the Gulf In other words the weather aspect of hurricanes is further aided by GW I read where the heat influx out of the Gulf region has a magnitude of 1 4 billion megawatts So that heat has to go somewhere and evaporation is an easier way for this to happen than just the water increasing in temperature So this heat energy goes into evaporation and mechanical energy in the form of a hurricane The Gulf of Mexico is one gigantic solar collector and the Gulf Stream is how the heat from that solar collector is distributed to Europe and elsewhere Our distribution loop got clogged with low density water and we had a backup of heat until our heater over heated and blew off steam in the form evaporating ocean water which made a swirling cloud called a hurricane Does this mean Europe will have a cooler winter if we have a strong hurricane season I made many assumptions and I apologize to those who know more about the science Nevertheless I would love someone more qualified than I am with the science to add or subtract from what I said to add more clarity If Dan is right on at least part of this then are there perhaps other GW induced factors that go into hurricanes perhaps even go into the decadal cycle which goes into hurricanes aside from SST Of course sea rise would make coastal land more vulnerable hurricanes more destructive I think destructive is a fine term for our anthropocentric focus here 29 Kirstin says 3 Sep 2005 at 6 28 PM Thank you I appreciate this blog very much and I think you are doing a very good job Kirstin 30 Pat Neuman says 3 Sep 2005 at 8 00 PM I think the term destructive power footnote 1 could use more discussion It was reported that Katrina was highly unusal for a combination of high intensity and large size I would like to see Katrina ranked with hurricanes of the past according to size and total power For example Katrina s size could be represented by the amount of land area square miles which experienced catgory 4 wind speeds I would also like to see a scale that would include size and wind speed parameters for ranking total power of hurricane for the U S My guess is that Katrina and Andrew were the most powerful combined wind speed and size hurricanes to hit the U S of the last three centuries or longer 31 Roger Pielke Jr says 3 Sep 2005 at 9 20 PM Re 24 I had no contact with anyone in NOAA other than my co authors with whom I worked on this paper just like I would anyone else irrespective of their employer I doubt that NOAA has a policy on climate change and I wouldn t co author a paper whose publication required approval by a government official Hope this clarifies 32 Pat Neuman says 4 Sep 2005 at 7 44 AM Re 31 Yes that helps Thank you 33 Jerry says 4 Sep 2005 at 11 55 AM There is NO DOUBT A CONNECTION 34 Terry says 4 Sep 2005 at 12 44 PM It would help if you could explain a step in the logic of this piece Higher temperatures mean higher energy levels but in thermodynamics it is the difference in temperatures that determines how much power a system outputs For instance a system with a heat sourec at 100 degrees and a heat sink at 50 degrees will produce more power than a system with a heat source at 120 degrees and a heat sink at 110 degrees even though the second system has higher temperatures So it would help me if you could explain the temperature difference that drives hurricane systems and how GW is expected to increase that temperature difference Or if I am wrong about this explain why temperature differences are not important Thanks Response Much of the power for the hurricanes comes from latent heat the condensation of atmospheric moisture as air parcels are raised Warmer air leads to more moisture roughly exponentially so no T diff would be needed William Response The amount of latent heat release depends on details such as the water vapour concentration of the ascending air parcels coming in at the bottom of the storm and of those that emerge at the top The amount of saturation water vapour is determined by the Calusius Clapeyron equation assuming local thermal equilibrium e s 10 11 40 2353 T where T is the temperature in degrees Kelvin absolute temperature Freezing temperature 0C 32F 273 155K produces a satiration vapour pressure of 611Pa It is well known that the temperature diminishes rapidly with height and the pressure drops as well hence the need for a cabin pressure system in airoplanes The cold temperature you refer to is to a large part determined by the height of the cloud tops in the hurricanes Cold T 210K rarified air is not capable of holding much moisture and a difference of a few degrees does not matter much there T 210K 1 6Pa T 220K 5 1Pa A change in the temperature at the warm end however has a much stronger impact on the water content of the incoming air parcels ascended into the storm T 295K 2653Pa T 305K 4844Pa Besides the air at surface level is more dense than aloft rasmus 35 Magnus says 4 Sep 2005 at 1 15 PM I just ran across this http www nhc noaa gov pastdec shtml that says that there have bean no increase in hurricanes that comes in on the mainland of US If I remember correctly I have read a statement somewhere that there have bean an increase of strong hurricanes over the Atlantic do you have any numbers of that And the reason why more havenâ t struck US is it just pure luck 36 Almuth Ernsting says 4 Sep 2005 at 1 18 PM Re 5 I think a study that looks at the probability of Hurricane Katrina having had the same destructive potential with say 0 5 degree C cooler SSTs would be really great I agree with Stefan s response that looking at the future is far more important the future after all is the reason for reducing emissions now When I look at reports in the media and public perception in general however any evidence that global warming is real and is already making extreme weather and hence terrible suffering more likely today is far far more powerful than the most terrifying prediction for 2100 The Hadley Centre study on the European heat wave was widely reported and I am sure changed some people s minds Public polls show that most people in the UK and US accept that climate change will threaten future generations but most are in denial about it affecting their lives and people s willingness to take action is directly linked to whether they think climate change will affect their own generation Re 6 Heiko Gerhauser states in 6 that mid latitude storms may have decreased since the middle ages and could be expected to decline with global warming I don t know about trends since the Middle Ages I do know that British storms have doubled over 50 years according to the Hadley Centre see http news bbc co uk 1 hi sci tech 3307447 stm 5D Hadley Centre climate forecasts are for more high intensity storms in Britain as global warming intensifies Scotland has just had the strongest storm in living memory this January which subsequently hit Scandinavia after increasing its wind speeds over the North Sea so it s not just us it seems Response Does climate change only affect future generations I am middle aged and expect to still be around in 2050 And the life expectancy of children born today goes beyond 2100 Future generations sounds abstract but climate change will strongly affect the lives of my generation and of our children And most people care a lot about the kind of future their children will have stefan 37 Heiko Gerhauser says 4 Sep 2005 at 7 33 PM Re 36 I suppose this thread shows again how difficult it is to keep politics out of the discussion politics in this context preferences for how climate change should be dealt with and a consequent desire to present information in a way to sway the public towards that preference The probability calculation Almuth proposes is tailor made for influencing the public towards greater action while a calculation that looked at say the impact of Kyoto in 2020 on the wind speed of a second Katrina compared that to the variability introduced by natural cycles and emphasised that this was based on models while there had been no conclusive trend in tropical cyclone wind speeds so far would be made with a different kind of advocacy in mind Pielke et al s paper is very clearly going in this direction One measure makes the impact of climate change action look near term large and certain while the other emphasises how small far out in the future and uncertain the benefits of any climate change action would be On British storms the link is messed up because of the bracket at the end just in case anybody else has trouble with it Maybe the climate experts on this site could address the subject of mid latitude storms in a bit more detail I gather that the main reason to expect them to decline is the lower pole equator temperature difference that climate change would bring with it and that this is the main driving force for mid latitude storms while SST are the most important variable for tropical storms IPCC in their 2001 report mention pressure changes as does the Hadley Centre but I am not clear whether this amounts to merely a shifting around of where stronger storms occur or a sufficient case to argue that the competing effect of the lower pole equator temperature difference would be overcome Re 6 I know that the true argument for acting relates to what ll happen beyond 2050 and that said action must be continued through much of the 21st century to have much effect and you say this clearly But there are plenty of people who do not realise this and when they watch a certain recently released movie on the subject or hear about the German environment minister linking Kyoto and Katrina they are easily misled into thinking otherwise Current climate disasters are much better for convincing the public than projections though they shouldn t be I know that the Kyoto will only do so little argument can be stretched too far to the point of suggesting climate action won t do anything in any case and I do see your viewpoint there though I think you do needlessly brush an ad hominem in the process of stating that viewpoint But you also know that whenever a major climate related disaster happens the media will ask scientists whether it s related to global warming and that these disasters will be used to justify Kyoto and that the immediacy of the benefit can easily be overstressed to the point where many people do believe that Bush s refusal to sign Kyoto directly caused Katrina or at least made it noticeably worse I think it is entirely appropriate to address that misconception On your other point I know that a major issue is how well and quickly we can adapt to the changing climate As you say it makes little difference whether sea level is 3 m higher or lower but if cities are built next to the present shore line adaptation has a cost I just don t share your opinion that the cost of adaptation would be high enough to off set the benefits or at least to off set them by enough that much climate change action now is a good investment As you don t include the economics of climate change on your site I think we can leave it at that difference of opinion without having to sling insults suggesting lower motives I also happen to disagree on the specific example of adaptation you chose to highlight High summer temperatures are exceedingly easy to adapt to nowadays which is why people are so happy to move to the South of the US or to take a summer holiday in Spain Climate change so far is equivalent to something like moving 100 km South in terms of maximum summer temperatures with decades to adapt The way to deal with this is air conditioning That works near immediately and is useful also in the present climate though it is energy intensive and therefore currently contributes to CO2 emissions I d bet that the death toll estimate is based on a year on year comparison and mostly relates to elderly people already close to death To claim that the increase in summer maximum temperatures in Europe is too rapid for adaptation and therefore responsible for increased death is a very weak argument much much weaker than that sea level rise will be too rapid for adaptation to have low costs Response Quick response to two of your points First what the german environment minister actually wrote in his much villified article published on Tuesday 30th was very much down the line of our post He wrote that no individual storm can directly be linked to global warming but that climate change is making extreme events more likely He used this to argue for climate protection measures finishing his article by stating that the international community should stretch out their hands to the US with a proposal for the future of an international climate policy Second you state that the casualties from the European heat wave were mostly elderly people already close to death Nice one And as you will know another standard skeptics argument Why not check the facts before you publish such claims on the web In France the mortality rate during the heat wave was statistically significantly increased in all age groups above 45 my age See Schär and Jendritzky Nature 2004 stefan 38 Stephen Berg says 4 Sep 2005 at 11 08 PM A paper examining the increase in temperature of the world s oceans over the last 50 years or so http www nodc noaa gov OC5 PDF PAPERS grlheat05 pdf I figured that it could be a benefit for the discussion on this thread 39 Lee A Arnold says 4 Sep 2005 at 11 11 PM With regard to the economic cost benefit analyses of global warming or of a climate treaty to brake it it should be pointed out that economists must ignore the alternate new pathways that the economy will doubtless take under the vibrancy of capitalism because these do not presently exist And in the other column they also also ignore the nonmonetized ecosystem services clean water clean air disease suppression etc provided to us by nature right now We can t even predict the present economy with much certainty so coming up with cost benefits under the new conditions while a valuable academic exercise is almost certainly useless You can argue that Katrina is likely to stimulate the GDP through rebuilding and that would be true but so what This is an old schoolyard truism usually known as the broken window argument go break a window raise the GDP You are not increasing the total welfare only getting it back to what it was And of course not tallying the incalculable suffering of the meantime We may never know whether Katrina is attributable to warming but the politics of it is clear it is of the magnitude which might be imagined in a climate catastrophe Anyone who doesn t take pause at this should be put under the sober care of a qualified psychiatrist I offer this last remark of course as a strictly scientific observation 40 Isaac Held says 4 Sep 2005 at 11 31 PM With regard to Williams answer to Terry 34 I believe that Terry is correct that it is temperature differences that are fundamental and not for the most part the temperature itself as Emanuel has discussed in a series of important papers on the maximum intensity that hurricanes can attain It is the temperature difference between the ocean surface and that of the upper level outflow that is crucial From this perspective one can see that the issue of hurricane intensity is linked with that of trends in upper tropospheric temperatures We should all hope that the models and data analyses which suggest that the tropics stays very close to a moist adiabat as it warms are correct If not and the upper troposphere warms less rapidly than the surface the temperature difference relevant for hurricane strength will increase that much faster Response This is an interesting point which deserves better discussion that I can do I m sticking with my view for the moment bolstered by the fact that everyone seems to correlate hurricanes against SST and I ve never seen anyone correlating them against upper temps I m not sure which KE papers you mean In http wind mit edu emanuel anthro2 htm he says everywhere we have looked the change in hurricane energy consumption follows very closely the change in tropical sea surface temperature William 41 James B Stephens says 5 Sep 2005 at 12 22 AM The solution is

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  • Storms & Global Warming II « RealClimate
    article by Richard Kerr in Science Atlantic Climate Pacemaker for Millennia Past Decades Hence may be of interest with regard to the AMO Atlantic Multidecadal Oscillation I assume this is the the 20 to 30 year cycle referred to in the NOAA link cited by Rasmus 14 dave says 10 Aug 2005 at 7 20 PM Re 1 Peilke s statement Hurricanes and Extreme Weather Events Anyone making assertions that changes in climate whether human caused or not are responsible for any part of the global trend of increasing disaster losses had better provide some new scientific evidence to back up such claims I agree with Pielke s statement Positive assertions must be backed up by solid evidence On another thread I said that the recent heat wave in Colorado seemed unusual in my view and here we are dealing with hurricane intensity and longevity Rasmus shot me down when I said that about the heat wave Even so they extreme events will still happen from time to time and if there are too many record events then this is improbable given an iid process Of course I could not statistically back up what I said However this from Pielke talking to the Rocky Mountain News Denver is not getting hotter in the summer and one measure of that is the number of consecutive days above 90 degrees Pielke said There were longer stretches of days above 90 degrees back in the early part of the 20th century and the end of the 19th century he said So we are in a heat wave right now but we re not in an unprecedented heat wave A 12 day stretch of 90 or above highs ended Sunday when the mercury in Denver peaked at 86 The city s longest streak of 90 or higher days is 18 which has happened twice in July 1874 and July 1901 But we also have this statement Boulder climatologist Klaus Wolter says the hot spell was the hottest five day period in Denver history It was unprecedented said Wolter who works at the National Oceanic and Atmospheric Administration s Climate Diagnostics Center The clear implication regarding Pielke is that the burden of proof is on the scientists to find statistically significant correlations and otherwise the negative conclusion is drawn regarding whether climate change is in the mix be it heat waves or heavy flooding monsoons or hurricane intensity If he s going to say that positive assertions require proof he can also say that negative assertions are not justified in the face of lack of data and scientific study So the truth is that the data trend has not been tracked and studied in almost all cases Climate change could be a factor but that is not known it is becoming more clear in the case of hurricane intensity if not frequency So the honest answer in statements to the press regarding extreme weather events is this climate change is happening and is possibly a factor in this weather or hurricane event but our current understanding shows no significant or some correlation There may or may not be a connection as our knowledge increases Some blanket statement that climate change is not involved Denver heat waves hurricane intensity record flooding is irresponsible nonsense since that is not known Absence of evidence is not evidence of absence 15 Mike Doran says 10 Aug 2005 at 10 12 PM 12 Rasmus Benestad http groups yahoo com group methanehydrateclub message 2487 Thank you Response I appreciate the explanation about capacitance after all it is a while I completed my first degree in physics and electronics Actually I think the issue of electrico dynamics veers off the subject of the post although I get Mike Doran s point that he doesn t believe so Yes I also did my masters in cloud micro physics some years agao and if my memory serves me right electrical phenomena play a role in cloud mircophysics But not in the way Mike Doran outlines unless the view has changed completely I think if it had we would read about it in Nature and Science I m open for new ideas and do not write off the idea of electrical phenomena playing a role in climate hence a discussion on the subject together with various curiosities such as Aurora Elves airglow Sprites the Van Allen belts and Lightening in my book Solar Activity and Earth s Climate 2002 Praxis Springer But at this stage there are still speculations so I think that a simplified view involving capacitance the sea and the ionosphere can be discussed further on the methanehydrateclub site and not under this post Thanks for your input Mike rasmus 16 David Ball says 11 Aug 2005 at 12 24 AM I think the thing that troubles me is that there are so few studies out there that actually look at real data and make no mistake about it model output are not data Weather is ingredients based If you get the right ingredients coming together in the proper measure at the proper time you get the weather This holds for everything from severe thunderstorms to synoptic and mesoscale scale weather systems Global warming is indeed likely to produce significant changes in the weather but only when the various ingredients change sufficiently to produce a trend Given the high interannual variability of many severe storm types and the fact that the impacts of GW are very much regional at least for now trying to identify trends is problematic at best At worst it s a fool s exercise because in many cases we shouldn t even expect to find a change in severity or type because the ingredients necessary for such a change to occur haven t changed suffiently yet This is not to say for a minute that we shouldn t be looking for trends in things like hurricane intensity just that finding or not finding a trend at this time doesn t prove a whole lot It most certainly doesn t mean that a trend won t appear 10 or 20 years down the road just that it may well not be here now I think that may be some of what Pielke is attempting to say Sometimes a hurricane is just a hurricane and a tornado is just a tornado and attempting to fit each and every one into some larger contextual framework isn t possible Response I would recommend reading the Science article by Kevin Trenberth Uncertainty in Hurricanes and Global Warming He discusses aspects of trends in hurricanes I do disagree in the view that model output is not data The important question is what do they represent rasmus 17 Shy Elf says 11 Aug 2005 at 7 04 AM Re 6 You have this correlation backwards The Gulf Stream circulation is about equal parts wind driven which is roughly constant in strength and deep convection driven which varies significnatly on decadal time scales The majority of the streamlines of this deep convection appear south of the equator with some of them distributed all over the world but the largest concentration just south of the Equator near the coast of Africa Consenquently the associated SST pattern is slightly cooler in the deep convection upwelling regions of the Equitorial Pacific and the Indian Ocean strongly cooler in the nearest deep convection source region of the South Atlantic near Africa and the Equator warm over the bulk of the North Atlantic strongly warmer where the gulf stream loses the largest portion of its heat near 50N 25W and strongly cooler near 45N 45W which turns out to be a back eddy of the Gulf Stream with increased transport of cold water from the north whenever the Gulf Stream is running quickly The change in the average SST should be slighly negative as this ciruclation transports extra heat to deep water We can check the current SST and see that this matches what is going on currently except for the cold region near 50N 25W which was there not too long ago but has recently disappeared so we appear to be in a phase of high deep water convection in the North Atlantic It would be nice there were more timely reporting of deep convection measurements Results from ship weather station M appear to indicate an all time over 50 years of records low in deep water production east of Greenland so presumably the bulk of the convection would have to be in the Labrador sea The warmpth in the southern USA and elsewhere north of the hurricane producing region has been as large a factor in the large number of storms this season as the actual SST where the storms are formed because it has decreased wind shear The decrease in deep water convection due to global warming fights the overall increase of temperatue due to GW Overall I m enclined to believe that GW is likely to decrease Atlantic hurricane formation rates slightly while significantly increasing storm formation rates in the Pacific and Indian oceans This result would be strongly dependent on the exact dynamic response of the Greenland ice sheet to surface meltwater which is modeled poorly in todays global models Re 10 I m sorry but this post seems mostly incoherrent to me and the link to growing crystals in DMSO solutions hardly seems relevant but you do raise some interesting points The solar wind since it is charged compresses the Earth s magnetic field and also interacts directly with cosmic rays and greatly lowers the amount which reach the Earth When it is low there will be more cosmic rays stopping in the statosphere where they form the nuclei of water droplets This results in more heat trapping stratospheric clouds and more hurricanes This effect has probably become much smaller in modern times since our stratosphere is now so dirty with jet exhaust 18 Shy Elf says 11 Aug 2005 at 7 21 AM Correction Deep North Atlantic slighly INCREASES global SSTs by decreasing the depth of the termocline in the upwelling regions hence decreasing the ocean s heat content resulting an a net increase in emission of energy by the ocean 19 Roger Pielke Jr says 11 Aug 2005 at 8 39 AM Re 14 You ve got your Roger Pielke s mixed up here Jr and Sr Happens every so often Father http ccc atmos colostate edu blog Son me http sciencepolicy colorado edu prometheus Re 1 the pugnatious challenge I ve had no substantive responses to this and I see none here It seems safe to say that there is no scientific basis for asserting a climate change signal human caused or otherwise underlying the decades long trend of escalting economic impacts related to extreme events But I remain open to other scientifically based perspectives Yes human influence on the climate is real and we might even now be able to document changes in the behavior of weather phenomena related to disasters e g Emanuel 2005 but we certainly haven t yet seen it in the impact record i e economic losses of extreme events And it may continue to be difficult to identify a climate change signal in the damage record for decades or longer into the future This has significance for how we ought to both debate the climate issue and think about policy See Sarewitz D and R A Pielke Jr 2005 Rising Tide The New Republic January 6 http sciencepolicy colorado edu admin publication files resourse 1694 2005 01 pdf 20 Ken says 11 Aug 2005 at 11 47 AM Are Hurricanes Increasing Ask A Georgia Pine Tree Centuries of hurricane records have been discovered in the rings of southeastern US pine trees they searched all the woody tissues for any sudden drops in a particular oxygen isotope oxygen 18 That is the hurricane signal http www geosociety org news pr 05 28 htm 21 Mike Doran says 11 Aug 2005 at 2 50 PM 18 19 Sly Elf http groups yahoo com group methanehydrateclub message 2489 22 dave says 12 Aug 2005 at 1 26 AM Re 19 You ve got your Roger Pielke s mixed up here Jr and Sr Happens every so often Not only do we have considerable complexity and uncertainty to deal with respect to more intense hurricanes and other extreme weather events but now I find out that there are multiple Pielkes My apologies about any mix up However my original point in 14 still stands Statements in the mainstream media TV print about the relationship to climate change continue to reflect what I said since no positive relationship between extreme events has been established therefore there is no relationship and given that the climate is changing the possibility of one is not reported I wonder what they re saying in the Spanish press right now given the extremely hot and dry conditions they are currently enduring Or what the Indian press is saying about the extraordinary monsoon of the last few weeks 23 Ferdinand Engelbeen says 15 Aug 2005 at 11 02 AM Shy re 11 I am not sure what drives what ocean currents which invoke air pressure differences or the opposite or both are working together as the motor of large scale oscillations What I have read somewhere I suppose in the ocean currents pages of the Miami University but their server seems to be down is that a strong NAO index with stronger SW winds pushes warm er water far more north which increases melting and this slows down the Gulf Stream leading to a less strong NAO index and so on Something similar happened in the past decade in the Indian Ocean where the weakening of southeasterly trade winds caused a major circulation of this ocean to wane by nearly 70 percent of its average strength During the period 1992 2000 the average sea surface temperature of the Indian Ocean increased by approximately 0 25 Celsius this may be the cause of an increased monsoon strength here or more hurricanes on other places 24 Albert says 16 Aug 2005 at 5 26 AM This result would be strongly dependent on the exact dynamic response of the Greenland ice sheet to surface meltwater which is modeled poorly in todays global models Yes human influence on the climate is real and we might even now be able to document changes in the behavior of weather phenomena related to disasters e g Emanuel 2005 but we certainly haven t yet seen it in the impact record i e economic losses of extreme events 25 Kooiti Masuda says 16 Aug 2005 at 4 56 PM I feel that someone in the Western Pacific should say something about storms there though this is not the area of my expertise Typhoon experts help I have browsed the papers of Emanuel 2005 and of Chan and Liu 2004 Though my institution has subscription of Nature the file of Emanuel s paper which I got was an incomplete one no figures no math formulas no substantial list of reference But a complete PDF file is available from the author s site at MIT http wind mit edu emanuel home html and a PDF of its supplement is also there Chan and Liu s paper discusses correlation of year to year values between SST and indices of strong TCs It is a not study of long term trends Chan and his colleagues have already discussed the relationship between ENSO and Western North Pacific TCs in Wang and Chan 2002 and other papers This time they examine whether local SST is important in addition to ENSO and their answer is no in the year to year time scale Their story is clearer when variability in the longer interdecadal time scale is excluded From that part I infer that the correlation between local SST and TC indices is likely to be positive in the longer time scale though it requires a specific study to establish such a relationship I am a little surprised to know Chan s previous finding that Western Pacific TCs are more active in the El Nino phase of ENSO My understanding which had not been updated since 1980s was that El Nino suppresses cumulus convection in the Western Pacific and thus suppresses TCs there as well I still think that the conclusion depends on the target area and seasons Chan and Liu took 120 180 E May November I think that suppression of TCs by El Nino prevails in the western part of the Western Pacific and mainly in winter and spring It is true that the area with SST above 27 deg C in the Central and Eastern Pacific is larger in the El Nino phase Probably the high SST area in the whole Pacific is larger then But El Nino also tends to suppress TCs in some regions where local SST is high enough Probably the correlation between the high SST area and the total TC activity is positive but it is a result of spatial aggregation of complicated phenomena Emanuel 2005 shows the correlation of smoothed time series of SST and Power Dissipation Index I think that the smoothing reduces the ENSO signal but that it does not eliminate it Thus it is difficult to connect the discussion of the paper with the ENSO and the rest view of Chan and Liu Emanuel has made a good effort to compensate for the inhomogeneity of data quality as he describes in the supplement But it is still a difficult issue As Morita and Watanabe 2005 reported the best track data shows decrease of the frequency of strong TCs in the 1990s in the area 15 30 N 120 150 E Morita refers to a data set compiled by Japan Meteorological Agency I think it is essentially the same as the Western Pacific part of the JTWC data set used by Emanuel and by Chan but I have not confirmed it In some more detail TCs with central pressure lower than 920 hPa decreased those around 950 hPa increased and those around 980 hPa decreased Though it cannot be denied that these are real trends Morita suspects that these are artifacts due to changes in observing practice Aircraft reconnaissance in the Pacific was phased out in 1987 and since then surface pressure have been determined by satellite image interpretation Dvorak method except occasionally by island stations or ships Morita s results suggest that the image interpretation underestimates very strong TCs typhoons but somewhat overestimates moderate ones TSs I am not sure whether this causes significant bias in Emanuel s PDI Also Morita s observation is about the specific region Dvorak method may have different sensitivity in different climatic regions When we discuss whether the influence of global warming has appeared in TCs there is a fundamental problem that we are not very sure about theoretically how TCs should react to greenhouse gas induced global warming For middle latitudes extratropical cyclones are the principal actor in the energy cycle in the atmosphere Therefore the total power of cyclones the number times the intensity in the whole mid latitude zone should somehow correspond to the global forcing If the characteristics of transient warming is similar to those of equilibrium warming the north south gradient of temperature will decease and therefore the total power of extratropical cyclones will decrease Things may not be so simple however even in this zone Increased water vapor will provide energy by latent heat release and somewhat compensate for the loss And perhaps more important role of moistening is to increase inhomogeneity within individual cyclones Surely the maximum rainfall rate will increase Also the maximum wind speed may increase despite of decreased average value There is no guarantee for such large scale determinism for TCs The essential feature of the tropical atmosphere is cumulus convection whose individual horizontal scale and time scale are of the order of 1 km and of hours The largest scale feature is the Hadley circulation whose upward branch is none other than the collective activity of cumulus convection The Hadley circulation requires cumulus convection but it does not require TCs Whether cumuli organize into TCs easterly waves Madden Julian oscillations or something else or maybe remain rather random is not constrained by global scale forcing If we assume large scale determinism we can have some conclusions which will be valid as long as the assumption is valid Emanuel s previous theoretical work Emanuel 1987 assumes that there is a circular vortex coupled with convection and discusses how strong it would be The GFDL model has more degree of freedom but their experiments assume a circular vortex as the initial condition It is reasonable that results of these studies are mutually consistent Global warming experiments with a 20 km grid actually spectral GCM of the Meteorological Research Institute MRI of Japan shows intensification of strong TCs consistent with the GFDL model study and increase of the life time of individual TCs as Emanuel suggests but also decrease of the total number of tropical storms Unfortunately the only on line information about that study I have found is a short abstract for the previous AMS meeting Oouchi et al 2005 Off line and in Japanese there is a little more information in the abstract volume of MSJ 2005 Spring Meeting presentation Nos A203 and A204 I am not sure whether the collective total power of TCs or Emanuel s PDI increases or decreases as climate warms in that model A caveat is that all GCMs as well many TC models including GFDL s that have been used for climate change experiments employ hydrostatic approximation and cumulus parameterization They assume some ways of self organization of cumulus convection which may or may not be true Non hydrostatic cloud resolving models are promising in reduction of this kind of uncertainty But climate simulation with these models requires much more computer resources than currently available Whether the society can afford the cost is another problem Another difficulty for the 21st century projection of TCs and also for the projection of tropical climate in general is that it is not certain how ENSO behaves as the mean climate warms With the same scenario of greenhouse gas concentration some coupled GCMs produce more EN like climate and others less EN like ENSO may be a kind of free mode which can shift either way We can say some small thing relatively confidently for those mid latitude areas which are sometimes affected by TCs Warmer local SST helps maintain TCs which happen to arrive there Thus we will encounter more cases of strong TCs there unless the situation at the area of TC generation changes much References added Emanuel K A 1987 The dependence of hurricane intensity on climate Nature 326 483 485 Morita M and Watanabe S 2005 On a problematic issue of the Dvorak method for observations of typhoons Have typhoons really become weaker than before in Japanese Meteorol Soc Japan 2005 Spring Meeting Presentation No C201 Oouchi K Yoshimura J Yoshimura H Mizuta R and Noda A 2005 Tropical cyclones in a greenhouse warmed climate a projection from a 20 km mesh global climate model Amer Meteorol Soc 2005 Annual Meeting Suki Manabe Symposium P1 1 http ams confex com ams Annual2005 techprogram paper 86839 htm Wang B and Chan J C L 2002 How strong ENSO events affect tropical storm activity over the western North Pacific J Climate 15 1643 1658 26 Mike Doran says 17 Aug 2005 at 1 20 AM 25 Kooiti Masuda http groups yahoo com group methanehydrateclub message 2507 Thank you Response Please confine the discussion to this site rasmus 27 Mike Doran says 17 Aug 2005 at 10 54 PM A highly critical commentary on Steve McIntyre s random climate model This OPINION is my own Thank you Response Please confine your discussion to this site rasmus 28 Gerald Machnee says 18 Aug 2005 at 7 07 PM The comments contained in the site referenced in 27 show the low levels to which this site has sunk There is no science in making such remarks and I am surprised nobody has remarked on it Response Link is removed rasmus 29 Mike Doran says 19 Aug 2005 at 2 33 AM The random approach of McIntyre runs up against entropy too But the so called skeptics fumble here to in my OPINION Lambert as the example My highly critical comments Response Please confine the main discussion on this site rasmus 30 Mike Doran says 19 Aug 2005 at 10 50 AM Gerald Machnee http intranet lternet edu archives documents Newsletters NetworkNews fall00 fall00 pg06 html Here is an example of a changing entropy pattern just like the increase in hurricane intensity brought about by microphysics changes which have occurred due directly to increases of CO2 changing the CONDUCTIVITY of oceans Of course there are other inputs and human activity altering bio modulations of those inputs but my OPINIONS which I post on our group our not the opinions of RealClimate They are my own Do you think that Lambert and McIntyre are advancing science 31 Kooiti Masuda says 22 Aug 2005 at 1 25 PM Re 25 I feel that I should add some clarification to my previous comment No 25 What I referred to by the wording large scale determinism a few different relationships They have similar logical structure but each of which may be valid or invalid independently of others 1 Whether the activity of cumulus convection is determined by the variables averaged over the grid box of numerical models 100 km scale for typical GCMs 20 km scale in the case of high resolution GCM of MRI 2 Whether the activity of cumulus convection in a TC is determined by the dynamics of the TC scale vortex as in the Theory of Emanuel 1987 for example 3 Whether the activity of TCs TC scale dynamics and cumulus convection together is determined by the global climatic condition SST atmospheric composition and general circulation In any of these it does not mean that every small scale detail is determined by the large scale condition Thus it is not rigorously determinism It means that the collective effect of small scale phenomena relevant for the large scale is determined by the large scale condition Also it does not mean that the cause and effect relationship is one way It is probably mutual But if the result of mutual interaction in a coarse grained view can be interpreted in the function of large scale variables only it can be said to be determined by the large scale in a sense Large scale determinism is one of good ways of framing hypotheses If it is correct it makes theoretical discussion simple and numerical modelling economical On the other hand it is not guaranteed to be valid I think that it is good that some scientists endorse it and some others are critical to it Both activities are necessary to promote our understanding of climate 32 Kooiti Masuda says 23 Aug 2005 at 12 58 AM Excuse me for deviating from the subject of the original posting I think that what I would like to say does not fit in other active threads on solar forcing and that it is relatively more appropriate to remain in Rasmus s thread Re 26 I do not fully understand the reasoning of Mike Doran involving electric fields and I tentatively agree with Rasmus s remarks on 10 and 12 about that Even though I think that the cloud chamber mechanism are at work in nature as suggested by Svensmark and others I expect that its magnitude is not significant among many kinds of forcing to the climate system Rasmus s article here on 6 Dec 2004 No 42 demonstrates that it is not the dominant forcing driving the global mean air temperature Its effects on precipitation and atmospheric disturbances are still arguable I guess that it is much weaker than the aerosol effect mentioned below but I do not have a demonstration yet I think that cloud microphysics does matter to climate While I do not think that GCMs as available today are useless I think that their results will be revised somewhat when we know more about clouds I think the largest problem is the effects of aerosols which act as cloud condensation nuclei In the context of IPCC it is known as indirect effect of aerosols The IPCC WG1 2001 report posed the problem and now experts are tackling it In that context mainly their effect to the global mean temperature is argued but their effect will surely modulate disturbances TCs included as well I think that this is also likely to be one of the major pathways connecting solar variability to climate Variation in the ultraviolet part of solar radiation modulates photochemistry in the stratosphere and some products of the reactions can modulate cloud microphysics I do not know direct evidence about cloud condensation nuclei but some suggesting modulation of chemistry of the lower atmosphere As cited by Bradley 1985 Section 5 5 4 but not in the 2nd edition of the book Zeller and Parker 1981 found 11 year cycles in the time series of nitrate content in the ice at South Pole Watanabe et al 1999 found the same signal at another location in Antarctica Watanabe et al 1998 found similar variation of hydrogen peroxide content Probably this effect is usually masked by variations in anthropogenic volcanic or biogenic aerosols and is revealed only in Antarctica where other signals are quiet Solar cycle variation of nitrates also suggests that we do not require global scale variation of temperature to explain some geological evidence of past solar cycles in lake sediments or shallow sea sediments It may suffice that nitrogen was the critical nutrient for the aquatic ecosystem in that area References about solar cycle variations of nitrates and hydrogen peroxide Bradley R S 1985 Quaternary Paleoclimatology Allen and Unwin later Chapman Hall Watanabe K Kamiyama K Watanabe O Satow K 1998 Evidence for an 11 year cycle of atmospheric H2O2 fluctuation recorded in an ice core at the coastal region East Antarctica J Meteorol Soc Japan 76 447 451 Watanabe K Satow K Kamiyama K Motoyama H Watanabe O 1999 Non sea salt sulfate and nitrate variations in the S25 core near the coastal region East Antarctica Polar Meteorology and Glaciology Nat l Inst Polar Res Tokyo 13 64 74 Zeller E J Parker B C 1981 Nitrate ion in Antarctic firn as a marker for solar activity Geophys Res Letters 8 895 8 33 S King says 24 Aug 2005 at 9 38 PM An article by Patrick J Michaels of the Cato Insitute throws cold water on Emanuel s Nature thesis http www cato org pub display php pub id 4249 He contends that Consider the recent Nature article If hurricanes had doubled in power in the last few decades as Emanuel claims the change would be obvious you wouldn t need a weatherman to know which way this wind was blowing All of these feuding scientists would have agreed on the facts long ago Damages caused by doubling the strength of hurricanes would be massive and increasing dramatically Figures on this are pretty easy to come by at least in the United States The insured value of property from Brownsville Texas to Eastport Maine our hurricane prone Atlantic Coast is greater than a year of our Gross Domestic Product If hurricanes had actually doubled in power the losses in the insurance industry would be catastrophic He then states You would think that reviewers of Emanuelâ s paper at Nature would have thought to ask whether in fact there was evidence for increasingly powerful storms But they didn t There is just no incentive in the scientific community to kill the remarkably fertile global warming goose a beast that feeds on public fears Does anyone here feel that there is any validity to Michael s arguement Response As far as I know the insurance costs have risen dramatically but I have only heard this second hand Please correct me if I m wrong It is also interesting to note the new tack taken by the contrarians the reference to insurance figures has previously by them been dismissed as not a good indicator according to my recollection I m not convinced by Michael s arguement but there is a point if people do not feel the impact of a climate change say in the future then it s not important yet Time will eventually tell who is wrong and who is right The objective of making scenarios for the future work assessed by the IPCC is to use the best of our knowledge and foresight in order to avoid making big mistakes that will have a future impact This is an important endevour for any highly advanced and civilized society rasmus 34 Mike Doran says 25 Aug 2005 at 12 19 PM Kooiti Thank you BTW Michaels is an EXTREME RWN and is agenda driven not science driven IMHO He has NO education in electrical or biological sciences Nada Response Mike please confine your comments to this site I will henceforth remove all your links to your own blog under my posts RC should not be used to advertise your own blog I don t know if that s the intension but I think that is the effect intended or not I want to explain my position on this subject It s great to use links to refer to published work news articles or other peoples essays but I think it s not when you point to your own blog where you in effect post a response to RC Furthermore by allowing such links would also mean relinquishing some control and we would face greater risk of objectionable links to unscientific material as one above that was deleted because of unacceptable personal characterisation rasmus 35 Joseph O Sullivan says 25 Aug 2005 at 2 55 PM Michaels op eds on the Cato site are political lobbying Cato is a political advocacy group for free market pro industry policies and not an independent academic or scientific institute Cato and the people and groups it represents are worried if climate change science is widely accepted regulations will be based on it To prevent these regulations Cato is criticizing climate science Raising valid questions about the science that regulations are based on is acceptable but misrepresenting science to affect the political process is not Cato and Michaels have a history of regularly misrepresenting climate change science science generally and environmental regulations This op ed by Michaels is no different He is trying to conflate Emanuel s measurement of TC intensity with economic damages but they are different measurements As a scientist he is not unsophisticated and he does know that these are not the same but he is saying that these are the same to sway the public and score political points His comment that climate scientists are exaggerating anthropogenic climate change to get more funding is worse He is trying to cover for groups who are fighting climate change regulation mostly because industries and the lobbying groups they fund like Cato will lose financially It s like fighting kids saying I know you are but what am I I personally think there is little validity to Michaels argument At least it s not as bad as Spencer pushing intelligent design creationism on TCS I tend to be very suspicious of anything Cato Marshall CEI and these other conservative lobbying groups say about science and environmental regulation 36 Roger Pielke Jr says 25 Aug 2005 at 3 44 PM Rasmus On the costs of hurricanes insured and total please see these two papers Pielke Jr R A and C W Landsea

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  • Some recent updates « RealClimate
    Since salt is for these purposes a conserved variable in the ocean mean changes in salinity can only occur through fresh water addition The only issue is where this freshwater comes from arctic sea ice groundwater discharge increasing rainfall or melting glaciers gavin 6 Roger Pielke Jr says 22 Jun 2005 at 9 31 AM I see no areas of significant substantive disagreement between Trenberth 2005 and Pielke et al in press Read the two papers Trenberth s paper is narrower e g focuses on Atlantic and does not consider societal impacts but where the two papers overlap there is a clear consensus For a more detailed perspective on this overlap see http sciencepolicy colorado edu prometheus archives climate change 000465consensus on hurrica html 7 Ferdinand Engelbeen says 28 Jun 2005 at 2 52 PM I have asked Ruth Curry about the origin of the large pulse of fresh water in the late sixties Here follows here answer It is believed that in the late 1950s and early 1960s freshwater and sea ice accumulated in the Beaufort Gyre as a consequence of the prevailing Arctic atmospheric circulation patterns anti cyclonic around an Arctic high pressure center Those atmospheric patterns shifted to cyclonic in the early to mid 1960s driving the accumulated freshwater and sea ice through Fram Strait the main source of the Great Salinity Anomaly in the late 1960s It is doubtful that the fresh water flow actually reversed The magnitude and sense of net fresh water flow between the Arctic and Nordic Seas is determined by the difference between poleward flowing saline Atlantic waters and southward flowing fresh waters By volume the fresh water always wins but both flows exhibit significant fluctuations with time Hence in some periods the net freshwater flow out of the Arctic may be enhanced or reduced The latter answer was not on what I asked as that was meant if a lower inflow of salty water via the Gulf Stream in negative NAO conditions may be the cause with relative constant fresh water inflow precipitation But it seems that the outflow of fresh water ice increased thus that doesn t point to less inflow from the GS 8 Steve Bloom says 5 Jul 2005 at 7 21 PM There s an important new study on aerosols another topic recently covered on RC http davidappell com archives 00000865 htm I have a Nature sub but somehow missed this I haven t had a chance to read the paper itself as yet but the abstract and discussion are to the effect that we could be looking at 6 to 10 degrees C by 2100 Interestingly this is the same range of temperature increase that climate prediction net got slapped down for postulating earlier this year Is this new study more credible Response See my latest post gavin Site Google Custom Search Recent Comments What is the best description of the greenhouse effect Jim Eager What is the best description of the greenhouse effect Patrick Eriksson

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  • Storms and Climate Change « RealClimate
    September 27 2105 Place Orlando Island off the SE coast of NCSA Scene SW Seawall Mickey Crichton Chief Climatologist for the New Confederate States Department of Coastal Defense gazes towards the inbound noon ferry arriving from the port city of Lakeland fifty miles to the southwest Although this is not an official visit Disney has given Mickey permission to examine the feverish efforts to strengthen the eastern and southern portions of the seawall Hurricane Johnnie a devastating Category 5 is projected to arrive in the next four to five days Although few people seriously expect it to breach the 120 foot high seawall surrounding this privately owned island city it could seriously tax the pumping system that keeps the tourist mecca dry Since purchasing it from the NCS government right after the revolution Disney has spent trillions on its defense system against the rising ocean but now this icon of the Empire seemed vulnerable to the forces of nature A few minutes ago Mickey had shuddered when the Secretary told him the news on the encrypted channel Tomorrow the Confederate Weather Service shall announce the first ever revision of the Saffir Simpson Scale Category 5 formerly defined as greater than 155 mph will now be defined as 155 184 mph Incredibly Hurricane Johnnie hovers between the new Category 6 185 214 mph and Category 7 greater than 215 mph Mickey must tell the Disney people before the CWT announcement The inbound noon ferry was still unloading as the outbound ferry approached the island dotted horizon on its way to Lakeland and the cruise ships there Until now the Disney Empire had flourished despite all the threats imposed by global warming Michael Eisner CEO of the fledgling empire in the early twenty first century believed in GW and prepared the company to take advantage of the coming events Historians say that he even revised the secret by laws set up by company founders Walt and Roy Disney Roy being a close friend of Mickey s infamous ancestor Michael Crichton fiercely opposed the changes but Eisner eventually won that battle before he retired in 2006 As a seasoned and talented climatologist Mickey was already worried about Johnnie even before the Secretary called The trends had been looking ominous for years but the official change of the Saffir Simpson Scale signaled a new era in the fight against The preceding excerpt from the prescient short story by John M Crichton III written in 2035 by the young great nephew of the famous twentieth century novelist finally galvanized the public and with it the Federal Government into action Sadly it was too late Although scientists and foreign governments had been urging the US to cut back CO2 emissions for decades the legacy of the second Bush administration and the influence wielded by his great uncle had been too strong The public had been in denial and the massive disinformation campaign by the fossil fuel industries had stymied any legislative effort to enforce cutbacks Now although the draconian laws passed in 2037 have cut CO2 emissions in half the US is in a state of near collapse Federal money diverted to the emissions effort has wiped out Social Security Most other unneeded programs such as environmental transportation education housing etc have been cut to the bone The Defense budget has tripled due to threats of invasion by the EU and the Asian Alliance Sea levels continue to rise at a rate never envisioned by climatologists and other scientists in the late twentieth and early twenty first centuries due to the unforeseen effects of 9 Tim M says 5 May 2005 at 2 56 AM Figure 1 starts in 1850 Since many tropical cyclones hurricanes don t make land fall and are of short duration isn t there likely to be under counting in the first part of the graph The data must be from ship based measurements so is double counting possible early on No Category 5 was observed until 1920 or so with poorer observations could the maximum intensity of cyclones have been missed seems like it I don t know the definitions of the categories but maybe it s splitting hairs for the early data to be separated so finely Thanks Tim M Response There is a chance of undercount in the early part of the record and I believe that nature would think the division of categories is fairly arbritrary as the windspeeds do not necessarily cluster at certain levels as far as I know anyway Perhaps windspeeds and pressure Fig 2 is a better thing to look at rasmus 10 Ferdinand Engelbeen says 5 May 2005 at 8 46 AM I have the impression that one need to look at a much longer time scale than the last 1 5 century From history we know that the most devastating storm floods in the North sea region were in colder climatic periods like the LIA See the chapter on Frequency of storms in Europe at http www2 sunysuffolk edu mandias lia little ice age html Even the last devastating flood in The Netherlands 1953 was during a slightly colder period Something similar can be seen in Antarctic ice cores far more dust is settled in the ice cores during ice ages than during interglacials This may be partly by dryer air and changes in vegetation but also by more severe winds storms during ice ages See e g http www climate unibe ch hutterli papers Roethlisberger2002grl c pdf Thus higher temperatures probably will reduce the frequency and severety of wind storms not increase them Or it may be that it is the temperature difference between regions or even equator and poles that drives wind speed storminess The temperature gradient between equator and poles is higher during ice ages than during interglacials Response I think that this may depend a bit on the type of storms that you are referring to Mid latitude storms are most active during winter i e cold season when the Arctic experiences polar nights and there is stron temperature gradients Your comments may well be true for these Hurricanes on the other hand are most active in the summer season and when sea surface temperatures are high rasmus 11 Mike Doran says 5 May 2005 at 10 07 AM Re Comment by Ferdinand Engelbeen â 5 May 2005 8 46 am I think you make an excellent point Ferdinand One theory is that the LIA was caused by changes in roiling patterns by the moon See http www pnas org cgi content full 070047197 I agree with this theory and take it one step farther that the gravity pattern changes are about roiling and outgassing of CO2 which then changes conductivity patterns The problem is that when you introduce CO2 as your varied input to this dynamic it is dependant to both LIA and LCO and it is my view that s why we are seeing an AMPLIFICATION With all things electrical the problem with amplification is INSTABILITY What appears to be going up twice as fast twice as quickly will come down the same way 12 John Finn says 5 May 2005 at 10 53 AM Re Max hurricane speed wind pressure data Do you need an account to access the raw data at the NOAA site Thanks Response No It took some searching to find If you click on the link to the R script you can get the URL you can also get R from http cran r project org runs on Windows Linux and Mac run the script and it will retrieve the data for you 13 HELMUT STAMM says 5 May 2005 at 3 34 PM GAVIN THANK YOU FOR THE SITE THERE APPEARS A WEALTH OF HARD DATA IN NAVEL ARCHIVES OF NUCLEAR SUBMARINES THAT OPERATE AT GREAT DEPTHS AND MAINTAIN LOGS ON OUTSIDE TEMPERTURES AND SALINITY ALL COUNTRIES WHO OPERATED THEM WITHOUT A COMPLEX MODEL COULD PROVIDE TIME LOCATION DEPTH OUTSIDE TEMPERTURE AND SALINITY DATA COULD BE SOLICITED WITH NATIONAL ANANIMITY AND COMPROMISING LITTLE WE COULD GLIMPSE INTO THE DYNAMICS THAT MOVE VAST QUANTITIES OF HEAT 14 Thor Olson says 5 May 2005 at 3 57 PM I ve been using hurricanes as a good measure of the maximum energy available in the atmosphere ie if more energy is present then you get more bigger hurricanes I differ by counting the width of the hurricane the amount of rain and the average windspeed as the relevant measures of relative energy Why is hurricane windspeed such an important consideration when it is more based on ideal conditions such as symetry On the frequency of the storms I note that the weather really didn t change much during Dec 04 and part of Jan 05 such that you had four distinct spots in the oceans at 90 intervals in the Southern hemisphere that showed substantial chilling compared to historical data This fits well with an increased circulation model where there is a competition of space for storms to form so they end up as static waves To get an exceptional number of storms you only have to be on the right side of a high pressure zone that herds the storms into a narrow path Voila you have Florida being hit with 4 hurricanes in 2004 because there was a high pressure off the East coast of the US that didn t vary much or break down This supports counting increased storms as an indication of climate change Would it not be better to track the high and low pressure systems that guide these storms 15 mfa says 6 May 2005 at 11 04 AM Could you point to standard climate physics texts I am a mathematician by training and I would like to learn about the technical aspects of the subject Or perhaps some review papers maybe even available on line I love the site and appreciate the fact that answers are by people actively working in the field Keep up the valuable work Thanks Michael Response Depends a bit on whether you mean basic atmospheric physics or of climate change The Climate System from the IPCC report and the rest of the report might help a bit Large Scale Dynamics of the Atmosphere has some good pointers esp James circ atmos which is suitable for mathematicians William Response One good reference is Robert Pearce s 2005 Why must hurricanes have eyes in Royal Meteorological Society s journal Weather vol 60 No 1 p 19 24 rasmus 16 Stickery says 7 May 2005 at 12 29 AM I actually find this post and discussion of it bizarre Has anyone bothered to read the re analysis project and not just go in and grab a bunch of numbers and plug them in and then start speculating It is clearly pointed out that the intensity is underrepresented in the data prior to air and satellite reconnaissance This was demonstrated in figures 3 4 of for hurricane Erin of the Re analysis project It is also clearly pointed out that the record is by no means complete for frequency or intensity Landsea was the principal investigator I am curious as to why he was not asked for input about accuracy In addition I might point out that the re analysis is not complete A complete re analysis for 1911 1943 remains to be done as well as a re analysis of intensity since 1944 As a Biologist by training much of the specific nuances of climate discussion gets out of my league pretty quickly However some pretty obvious questions about this reporting came to mind pretty quickly and were easily confirmed I doubt as a scientist I would try to use admitted woefully inadequate old historical data and combine it with very sensitive modern data and make leading statements about emerging signs of change and that it should be a part of normal scientific discourse Personally I am all for scientific discourse but not one that uses very subjective data as clearly pointed out in the re analysis of data at the NOAA Hurricane Research Center as strength of the argument One question I ask Do you not find it curious that in figure 2 Maximum Hurricane speed Min pressure graph of this Rasmus post that the shift to lower pressures was abrupt starting in the late 60s early 70 s This makes me wonder if what we are seeing is an artifact of how pressures were either measured or calculated Perhaps a re analysis of the data since 1944 will clear this question up To conclude I will add that the investigators of the re analysis project had the following conclusion for Cycles of hurricane activity These records reflect the existence of cycles of hurricane activity rather than trends toward more frequent or stronger hurricanes http www aoml noaa gov hrd hurdat Documentation html Response You are right that the data probably may not be 100 representative due to improved the fact that the observational capabilities have improved over time and the fact that most storms nowadays are detected whereas some may have gone undetected in the past It s not just the observational systems but also the fact that we often can identicfy in weather forecasts model simulations conditions that are favourale for such storms so that we know in advance when too keep a watchful eye But as far as I know this data is the best information that we have about past hurricanes storms Even if it s not 100 perfect it s still interesting to analyse it would my opinion it would be silly not to I am aware about possible limitations of these data and therefore included the link at the bottom but these are still the best informaton that we have Furthermore there have been independent measurements analysis of dew point temperature from radiosondes in the Tropics But I don t understand why you call this discussion bizzare I can agree that the Disney comment can be characterised as bizzare but do you really mean that a discussion of data is bizarre if the data may contain errors rasmus 17 CharlieT says 7 May 2005 at 4 05 AM Rasmus How was peak windspeed measured assessed with the early manual run of wind type cup anemometers Were they on open topped 10m lattice towers and how often would one find an observer standing on the top of these during 300mph storms I appreciate that UKMO electric remote anemometers probably lagged being US ones but in 1939 the UK type was a run of wind pattern that ran an bell after a given number of turns The Generator type anemometers only became UK std during WW2 Looking at the post 1945 data of your plot there is no upward trend in windspeed indeed it declines slightly Response You re of course right if you are a bit critical about the wind speeds and central pressures You would risk being blown away if you tried to measure the maximum wind speed of a hurricane or the pressure drop in a hurricanes eye I did not make such measurements and presume that they have been inferred from other storm characteristics In the modern time Doppler shift measured by radar can nevertheless give more accurate estimates Therefore I emphasised that the analysis presented here took the data at face value this is the best information we presently have at hand rasmus 18 Gary says 7 May 2005 at 3 30 PM Let me pass on some information which i have come across in the past few weeks This information was sent to me from NHC to which i wish to thank for there response to my questions There as been a above normal levels of activity since 1995 average seasonal activity in the atlantic basin is 9 8 named storms of which 5 8 became hurricanes Just for comparison in 2004 there was 15 named storms 9 of which became hurricanes and 6 of the 9 hurricanes were major with winds of 100 mph the years 1995 2000 experianced the highest level of north atlantic hurricane activity on reliable record Compared with the general low activity of the previous 24 years 1971 1994 the past 6 years have seen a doubling of overall acidity for the whole basin a 2 5 fold increase in major hurricanes 50 meters per second and a 5 fold increase in hurricanes affecting the caribbean The greater activity results from simultaneous increase in north atlantic sea surface temperatures and decreases in vertical wind shear Because these changes exhibit a multi decadel time scale the present high level of hurricane activity is likely to persist for an additional 10 to 40 years I would also like to add that the seasonal outlook for 2005 should be due mid may This is issued by NOAA Once again i would like to thank all the people who keep us all informed on issues of great importance 19 Steve Curtis says 7 May 2005 at 10 47 PM Comment 19 says Compared with the general low activity of the previous 24 years 1971 1994 the past 6 years have seen a doubling of overall acidity for the whole basin What would be the conclusions you would draw from the activity over the 25 years 1945 1970 compared to the past 6 years and why choose 6yrs Do you allow for a greater variation in a 6 yr period than a 25yr period 20 Stickery says 8 May 2005 at 9 38 PM rasmus I do indeed find the post and subsequent discussion bizarre You use words such as may and might not be 100 in your posts when words such as likely contains errors is more accurate This is underselling the limitations of the data Both Neumann et al 1993 and Landsea 1993 recommend only utilizing data since 1944 for computing climatological statistics I remind everyone that Landsea is one of

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  • El Niño/Southern Oscillation (“ENSO”) « RealClimate
    et al 2015 Part III Response to Nic Lewis SteveS Marvel et al 2015 Part III Response to Nic Lewis steve s Marvel et al 2015 Part III Response to Nic Lewis Andrew Kerber Blizzard Jonas and the slowdown of the Gulf Stream System Hank Roberts Blizzard Jonas and the slowdown of the Gulf Stream System doiknow Marvel et al 2015 Part III Response to Nic Lewis MartinM Anti scientists Don McKenzie Marvel et al 2015 Part III Response to Nic Lewis Matt Skaggs Anti scientists mikeworst New On line Classes and Models Marcus Pages Acronym index Data Sources Categories Climate Science Aerosols Arctic and Antarctic Carbon cycle Climate impacts Climate modelling El Nino Geoengineering Greenhouse gases Hurricanes Instrumental Record IPCC Oceans Paleoclimate Sun earth connections Communicating Climate Reporting on climate skeptics Extras Attic Comment Policy Contributor Bio s FAQ Glossary In the News Reviews Supplemental data Tutorials hydrological cycle Open thread RC Forum Scientific practice statistics The Bore Hole Books Contributors Highlights Dummies Guide to the latest Hockey Stick controversy El Nino Global Warming and Anomalous U S Winter Warmth Hurricanes and Global Warming Myth vs Fact Regarding the Hockey Stick On attribution On mismatches between models and observations On Sensitivity Part I Tropical Glacier Retreat Water Vapour feedback or forcing Welcome to RealClimate Other Opinions A Few Things Ill Considered Accuweather Climate Blog And Then There s Physics Andrew Dessler Brave New Climate C2ES Christian Science Monitor Climate Change Education Climate Communication Climate Matters Columbia Climate Science Watch ClimateArk ClimateConservative Org Climatedenial org ClimatePhys ClimateProgress ClimateSight Cntr for Enviro Journalism Deep Climate Deltoid deSmogBlog DotEarth Earth Discovery Channel Ecologically Orientated Effets de Terre FR George Monbiot globalchange Grist Climate and Energy Horatio Algeranon Hot Topic HotWhopper James Empty Blog Jeff Masters Wunder Blog John Fleck Kate has things

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    doiknow What is the best description of the greenhouse effect James Powell Unforced Variations Feb 2016 Jim Galasyn With Inline Responses Marvel et al 2015 Part III Response to Nic Lewis SteveS Marvel et al 2015 Part III Response to Nic Lewis steve s Marvel et al 2015 Part III Response to Nic Lewis Andrew Kerber Blizzard Jonas and the slowdown of the Gulf Stream System Hank Roberts Blizzard Jonas and the slowdown of the Gulf Stream System doiknow Marvel et al 2015 Part III Response to Nic Lewis MartinM Anti scientists Don McKenzie Marvel et al 2015 Part III Response to Nic Lewis Matt Skaggs Anti scientists mikeworst New On line Classes and Models Marcus Pages Acronym index Data Sources Categories Climate Science Aerosols Arctic and Antarctic Carbon cycle Climate impacts Climate modelling El Nino Geoengineering Greenhouse gases Hurricanes Instrumental Record IPCC Oceans Paleoclimate Sun earth connections Communicating Climate Reporting on climate skeptics Extras Attic Comment Policy Contributor Bio s FAQ Glossary In the News Reviews Supplemental data Tutorials hydrological cycle Open thread RC Forum Scientific practice statistics The Bore Hole Books Contributors Highlights Dummies Guide to the latest Hockey Stick controversy El Nino Global Warming and Anomalous U S Winter Warmth Hurricanes and Global Warming Myth vs Fact Regarding the Hockey Stick On attribution On mismatches between models and observations On Sensitivity Part I Tropical Glacier Retreat Water Vapour feedback or forcing Welcome to RealClimate Other Opinions A Few Things Ill Considered Accuweather Climate Blog And Then There s Physics Andrew Dessler Brave New Climate C2ES Christian Science Monitor Climate Change Education Climate Communication Climate Matters Columbia Climate Science Watch ClimateArk ClimateConservative Org Climatedenial org ClimatePhys ClimateProgress ClimateSight Cntr for Enviro Journalism Deep Climate Deltoid deSmogBlog DotEarth Earth Discovery Channel Ecologically Orientated Effets de Terre FR George Monbiot

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  • Huracanes y calentamiento global ¿Hay conexión? « RealClimate
    not common near Brownsville I wonder if he was talking about hail closer to the center of Emily which for all I know might be unusual My memory of basic meteorology is that thunderstorms require hot and cold air masses to form which I suppose would cause hail to not be expected very near the eye of a hurricane even if the hurricane was pushing into a cold air mass Finally I doubt that the size of the hailstones is very meaningful since large hail could be expected from energetic thunderstorms and hurricane associated thunderstorms should be on the energetic side 68 wayne davidson says 7 Sep 2005 at 2 39 PM Have not heard it yet Is good to say that GW has no or very little effect on Hurricanes but would appreciate an explanation That would be better Contradicting simple atmospheric physics demands no less like world wide increase in water vapour density triggered by greater SST s and plain warmer air causations Proposing it has no effect on cyclones rings like a slogan not science An explanation aside from vague unimpressive assertions would be appreciated Hurricanes are not that dissimilar to cyclones they die as typical cyclones so lets say that you are not an expert on hurricanes then you may have an opinion on lesser meteorological entities The question is simple does warmer moist air create stronger cyclones I rather think the answer is positive and that answers about GW questions are simple just like the meaning of glaciers disappearing everywhere 69 Roger Pielke Jr says 7 Sep 2005 at 2 55 PM Pat 64 1 A change in the size of storms just like changes in frequency or various measures of intensity could certainly have societal implications The question is whether we can observe the effects of changes in the behavior of storms in the impacts record e g we do see pronounced differences in impacts according to the phase of ENSO El Nino La Nina So far we haven t seen evidence of significant changes in the impacts record We may see them in the future but not yet 2 I can tell you definatively that our paper was not subject to any approval up the chain of command Though we should be so lucky that the views expressed would be reflected as official policies Again our paper is consistent with Emanuel 2005 and Trenberth 2005 and a new study soon to be published The debate over this issue exists only in media statements and advocacy efforts and not in the peer reviewed literature Clearly Gray and Trenberth for example have different expectations about what future research will show but until that research is conducted and published I think our paper is an accurate assessment of the current state of knowledge on this topic as reflected in the literature Sooner or later it will be out of date as new work is published and then it ll be time for an updated assessment 70 Pat Neuman says 7 Sep 2005 at 4 09 PM 1 Francis 2004 and Katrina 2005 were unusually large right Does anyone know of plans to study what goes into determining the diameter of hurricanes and if size has increased on average recently We won t see any evidence of change unless we study this 2 I still think some kind of discussion and nod of approval from the higher ups had to be given or else it could be that the higher ups concluded that the authors involved in your article have a record indicating they d lean toward a position of no evidence shown in the historical record for a connection between hurricanes and global warming 71 Roger Pielke Jr says 7 Sep 2005 at 4 54 PM Pat 70 You ve mischaracterized our paper We cite Emanuel 2005 and describe it as suggestive of evidence of a connection of hurricanes and global warming 72 Lynn Vincentnathan says 7 Sep 2005 at 4 59 PM This may be totally off since I know squat about climate science the high powered statistical programs used but when there is a dearth of data in the social sciences not enough to give low enough p values on correlations regressions simply due to small numbers of data which is sometimes due to loading in too many control variables we sometimes turn to chi square log linear analysis to see if actual data reveal patterns incongruent with expected patterns In this vein could say log linear analysis be used to see if there were a lack of match between the natural decadal patterns since we have a good idea about them and the actual patterns now occurring currently since we have the actual data on them Forgive me if I m way off on this 73 Roger Pielke Jr says 7 Sep 2005 at 5 15 PM Stefan I have just come across your comments above Re 47 I can t read German I wish I could so if you d be kind enough to email to me a translation of the quote I d be happy to respond I did speak to the reporter for quite a while so I d be disappointed to be misquoted but it happens Response Headline issue 36 p 124 Roller coaster of monster storms number and strength of hurricanes is increasing but this has nothing to do with global warming The text says Human caused global warming however has nothing to do with the increasing storm chaos A connection between greenhouse effect and hurricanes is so far not proven says Pielke This is my imperfect translation The first sentence before the direct quote uses a tense which I think cannot be easily put into english which makes it an indirect quote from you rather than a statement of the journalist This indirect quote picked up in the headline is plain wrong as you will agree At most one could say we are not certain whether or not hurricane activity is linked to global warming The direct quote is technically correct in that nothing is ever definitely proven in the Earth sciences But one should be clear that there is reasonably good evidence for such a connection both from models and data see the two figures in our post above stefan Re 49 Emanuel s point and my point are one and the same Simply put his PDI metric is not a measure of destructiveness While there may indeed be changes going on in the characteristics of storms themselves this does not mean that those changes are at all meaningful from a policy perspective Think of it this way if there is no chance of observing the effects of changes in PDI in the global impacts record for 50 years Emanuel s estimate and over that same time period we expect damage to increase in real terms by up to a factor of 32 a real doubling in damages every 10 15 years then I think that it is safe and also responsible to assert that over that time period the only policies that can have a discernable effect on tropical cyclone damage around the world will necessarily be adaptive Response Emanuel s estimate means that globally the power of hurricanes has increased by 75 while tropical SST has increased by 0 5 ºC in the hurricane season and these two are linked by physical theory models and by statistical correlation This remains a real increase and there is no reason to assume that it is not linked to a similar increase in damage even if this cannot be proven from data because they are too noisy Bad signal noise ratio does not mean there is no signal as Emanuel shows in his example calculation bad signal noise is expected here despite a large signal simply because the data are very noisy From current understanding it is reasonable to assume that further warming will contribute to a further increase in hurricane damage and not by a small amount In my opinion this is one of many reasons why it is wise to stop the warming before it goes too far Putting more people and values into harms way by settling on a highly vulnerable coastline is also likely to increase hurricane damage I think it is a pointless discussion what is worse neither adding a lot more greenhouse gases to the atmosphere nor allowing a lot of development along such a coast without proper hurricane protection measures seem wise policies to me stefan 74 Michael Jankowski says 7 Sep 2005 at 5 20 PM RE 70 http hurricanes noaa gov prepare structure htm states Typical hurricanes are about 300 miles wide although they can vary considerably size is not necessarily an indication of hurricane intensity Hurricane Andrew 1992 the most devastating hurricane of this century was a relatively small hurricane Frances was huge but I can t find a number I ve found links saying the size of Texas which would put it in the 700 mile range Katrina was about 500 miles wide at some point By comparison Andrew was just 60 miles wide I think it s worth noting that Katrina was a Category 1 when it struck south Florida If she had veered northward at that point we wouldn t be talking so much about hurricanes right now Katrina would ve been a relatively minor Florida hurricane and probably mostly forgotten 75 Harold Brooks says 7 Sep 2005 at 5 49 PM Re 66 Thunderstorms in hurricane environments typically don t have strong updrafts The temperature profile is close to moist adiabatic and as such there s little convective available potential energy Also since the environments are generally warm through the depth of the hurricane there s a long distance between the freezing level and the ground Hail is generally rare with hurricanes and in fact so is lightning in comparison with mid latitude continental thunderstorms Re 70 2 I m not one of Roger s NOAA co authors but I am a NOAA author of other papers I ve never had to get a nod of approval from higher ups for the content of any paper I ve published even though some of them have questioned NOAA policies and or future directions 76 Pat Neuman says 7 Sep 2005 at 7 50 PM Re 71 Roger I don t think I mischaracterized your paper I ll take another look BTW did your co authors spend government time doing work on the paper Re 73 thanks for the info When Katrina struck south Florida was it nearly as wide as when it hit Louisianna Mississippi Did Katrina come ashore with widespread heavy rain like Francis Re 75 Did you use government time to work on your papers When date yrs did you work on these papers Did you include disclaimers on the papers I think the subject of global warming climate change is a whole different ball game 77 Isaac Held says 7 Sep 2005 at 8 59 PM I would like to comment on the argument in the initial posting in this thread that one can compare the importance of decadal variability in the Atlantic and greenhouse gas increases for hurricanes by simply comparing the increases in SSTs that they cause This is also a continuation of my comment in 40 Suppose for the sake of argument that the Atlantic internal variations are uncorrelated with the Indo pacific but that the latter becuase it provides the deepest most intense convection on average controls the tropical tropospheric temperatures above the boundary layer which we think of as being uniform horizontally Then when the internal variability of the Atlantic creates warm SSTs it also creates a more unstable troposphere In contrast greenhouse gases warm both the Atlantic and the Indo pacific and therefore they warm both the Atlantic SSTs and the tropical troposphere hopefully with no change in stability to lowest order By the same argument ENSO by warming the troposphere with only small effects in Atlantic SSTs would stabilize the Atlantic Whether one thinks about buoyancy in this simple way or one uses the entropy base arguments for potential intensity of hurricanes the sense is the same internal variability should be more important for hurricanes than global warming of comparable SST amplitude Response Isaac I don t think anyone is claiming that SSTs alone are determinant since as you correctly point out tropospheric temperatures and the stability of the atmospheric profile are obviously important However to the extent that SSTs are influential it makes sense to assess the possible contribution of a global warming signal to the SST variability Where your argument might break down is in the assumption that GW would cause uniform warming across the tropics Given the much greater internal variability in the Pacific and the arguments of Cane et al that doesn t necessarily hold true though it would be worth examining further gavin Response Dear Isaac you ve got a potentially valid point that hinges on the question which we have not really clarified yet how important are differences in temperature and how important is the absolute value of temperature which does come in due to all the non linearities e g Clausius Clapeyron which are not just small second order effects One preliminary test if your argument is right the correlation of SST and hurricane intensity should be much higher in the Atlantic compared to the Pacific or the global tropical average That s not the case see Kerry Emanuel s second to last graph here stefan 78 Eli Rabett says 7 Sep 2005 at 10 26 PM To Pat Neuman and Roger Pielke while I cannot speak for NOAA most of the national labs I am familiar with have an internal review policy for scientific papers which functions to insure quality personal axes to grind are another story Among other things that they look for is that no confidential material is being disclosed and certain other policies are adhered to Here is one example http www ncnr nist gov WERB html Here is a general discussion of the issue for national labs It appears on first glance that NOAA relies on external peer review http www gao gov archive 1999 rc99099 pdf To Michael Jankowski it appears that you never saw a headline that says man falls asleep plows into tree at 70 dies Please you have constructed a stawman There are enough people who die in high speed crashes when they fall asleep At slower speeds they are only mangled 79 Harold Brooks says 7 Sep 2005 at 11 06 PM Re 76 Yes it was on government time I worked on the papers from 1992 to the present and continue to do so No disclaimers were put on them I have seen no difference in any climate related papers A quick glance at NCDC climate change papers shows no disclaimers either on the first several I looked at on the AMS archive and they were all supportive of significant climate change in recent years 80 Pat Neuman says 8 Sep 2005 at 9 03 AM Re 78 After reviewing your linked refererences I think many of the agencies or offices which are under the NOAA umbrella have their own internal review policy for scientific papers This will likely be my final post here on this subject 81 Michael Jankowski says 8 Sep 2005 at 9 34 AM Re 78 You continue to twist my analogy immensely ignore my points and argue against points I have never made I am sure we agree that assuming all other things are equal a hurricane with higher wind speeds is more destructive than a hurricane with lesser wind speeds But I am not sure that you agree however that all other things are not necessarily going to be equal It seems reasonable to me that if AGW can significantly affect wind speeds in hurricanes and weather patterns throughout the world then other factors determining the paths and destructiveness of hurricanes can also be affected by AGW Some may be generally bad some may be generally good and some may be either good or bad on a case by case basis Does this not seem reasonable to you 82 Roger Pielke Jr says 8 Sep 2005 at 11 30 AM Re 73 Stefan Thanks for these comments we may simply agree to disagree on these points Some additional thoughts 1 You write This remains a real increase and there is no reason to assume that it is not linked to a similar increase in damage even if this cannot be proven from data because they are too noisy If you can t see a signal in a noisy record then by definition that signal is not large with respect to other relevant factors If I can t see a climate signal in the damage record I agree with you that this does not mean that a signal does not exist but it does lead one to conclude that the signal has not thus far been important from an impacts policy perspective Policy deals with or at least should deal with causing detectable effects not addressing effects that cannot be detected And again Emanuel himselves estimates 50 years before any signal can even be detected Response then by definition that signal is not large with respect to other relevant factors Nope not quite logical That signal then is not large compared to the purely random stochastic elements Kerry s example shows we could not remotely prove even a 75 increase from landfall data If global warming has caused a 75 increase in hurricane damage then this is definitely policy relevant no matter whether your damage statistics can attribute it or are just too noisy for that I suspect you are thinking if my statistics don t show the effect then it can t be a serious real effect But that s not true Remember the loaded dice assume your friend rolls it 10 times and gets 4 sixes Assume without the dice being loaded he would have gotten 2 sixes So loading the dice had a huge impact Yet by analysing the statistics of those 10 rolls there s no way you could have demonstrated that the dice is loaded You couldn t tell whether the 4 sixes occurred just by pure chance But if for each six you were losing 1000 to your friend this would be highly policy relevant for you you would stop playing with him if you had good reason to think his dice were loaded You would stop playing if you had some other indirect evidence that the dice are loaded say like Kerry Emanuel telling you after having x rayed the dice You then wouldn t play on until your loss statistics unequivocally prove that the dice were loaded unless you re stupid Do the maths how many rounds would you have to keep playing with doubled odds for losing until you can prove at the 95 confidence level that you re being cheated Would you really keep playing all those rounds brushing aside Kerry s x ray pictures with the argument I don t see statistically significant losses yet my losses are large but still within the even larger bounds of random chance I wouldn t stefan 2 You write I think it is a pointless discussion what is worse climate change or societal vulnerability I m surprised at this statement Policy has to be based on an assessment of alternative courses of action and justifications for action that lend themselves to political accountability If one has a goal of addressing the future impacts of extreme events on human society then the most important question from a policy perspective must be What options do we have to act and what are our expectations for the consequences of those alteratives Understanding the reasons underlying undersirable outcomes must be part of our research portfolio lest we act on assumption hunch and political predispositions none of which in my view are as effective a basis for action than science I agree with you 100 that we should address both greenhouse gases and societal vulnerability but we should not pretend and yes until it is backed by science it is pretending that these issues are one and the same They are not There are good justifications for reducing greenhouse gas emissions but having an discernable influence on future hurricane dmaages is not among them Response Of course they are not the same But you have to be clear that the two effects multiply they do not just add up Above 73 you juxtapose a 32 fold increase in vulnerability due to population etc to a non discernible climate effect say a 2 fold increase in hurricane power roughly as seen in Fig 2 of the post above suggesting the latter thus must be unimportant That s not the case If your 32 times larger values are struck by a twice as damaging hurricane the resulting damage would be 64 times larger In numbers assume that decades ago the damage from hurricanes would have been 3 billion Now after 32 fold increase in values the same hurricanes would have caused 100 billion But if hurricane power had doubled that would rise to 200 billion So even though doubling sounds like a lot less than a 32 fold increase this is highly deceptive It still remains that in this theoretical example half the damage is due to climatic effects not population And that remains true even if the data are too noisy to prove the twofold increase statistically you still have to pay this bill see the example with the dice above Perhaps I m biased because I m a physicist not a statistician but to me it is clear that physical evidence like our physical understanding of how CO2 affects SST and how SST affects hurricanes gives you warning of the loaded dice long before you can prove it from the damage statistics Kerry hand me those x ray pictures I m not gonna keep playing this game ignoring the physical evidence waiting until the losses are so huge that even very noisy statistics become unequivocal stefan 83 Lynn Vincentnathan says 8 Sep 2005 at 12 28 PM RE 75 thanks for your response It was mid July we re a subtropical area lat 25 9N and we were in the throws of El Cunecula regular but intensified summer heat wave when Emily with hailstones came So I guess our weatherman was right hailstone are unusual in our hurricanes RE 79 great so glad at least some of my taxes are going in the right direction I think all branches of government should be addressing GW in their own ways afterall it IS global which includes the U S I keep writing my reps What are you doing about this and they keep responding The science isn t in yet and I keep responding Yes it is more than enough for policy decisions Of course they get their science from the WSJ So it is indeed good that a few in gov are actually into the science of GW Just too bad those that make life death decisions for us are not And before the contrarians who claim science should be kept clean of policy politics jump on this I agree with you I want science to strive after objectivity let the GW loaded dice fall where they may This post is not violating that principle rather it is critiquing the situation of policy politics keeping clean of science which they should NOT do because that amounts to the blind leading the blind into very troubled waters As a social scientist I am interested in this perspective Our Enlightenment mindset of analysis cutting up compartmentalization div of labor pulling apart the clock to see how it works great for most science not so great for all of life I think in science life we now need some synthesis bringing together putting the clock back together connecting science to policy bringing in more variables into science an integration of the physcial sciences with the social behavior sciences perhaps with the humanities the university with laypersons United we stand divided we may fall Part of this problematic Enlightenment mindset is the either or focus I liked Stefan s response to 73 Why can t we do both 1 better prepare for the effects of GW AND 2 try to reduce GW The money we save from 2 could be plowed back into doing 1 84 wayne davidson says 8 Sep 2005 at 2 34 PM 73 There are good justifications for reducing greenhouse gas emissions but having an discernable influence on future hurricane dmaages is not among them Is a statement which defies logic the very source of energy creating powerful hurricanes is greater moisture generated by more heat I rather like an explanation are hurricanes not heat dependent Never mind destruction statistics which vary according to hurricane paths The implication of this statement reads like GW has no disercnable influence on hurricanes like GW has nothing to do with warmer air 85 Roger Pielke Jr says 8 Sep 2005 at 2 49 PM Re 84 It is possible that GW has a discernable influence on hurricanes and yet has no discernable influence on hurricane impacts however measured For an undersatnding of how this can be the case see this paper Pielke Jr R A and D Sarewitz 2005 Bringing Society back into the Climate Debate Population and Environment Volume 26 Number 3 pp 255 268 http sciencepolicy colorado edu admin publication files resourse 1688 2005 25 pdf And I agree with Lynn 83 we can and should be doing both sorts of things but to do so effectively means not conflating them as one and the same 86 Joseph O Sullivan says 8 Sep 2005 at 4 17 PM I think Roger Peilke Jr is asking a hybrid climate science regulation question On the scientific side climate modeling and physics show a potential increase in TC intensity that correlates to global warming and now there is evidence that this is actually happening This increase in TC intensity has not had a measurable socio economic impact and possible further intensity increases might not have a large socio economic impact The question then is what kind of regulatory action should be based on this information I think it s a reasonable policy question There is some good info about TCs and climate change Pew has a release http www pewclimate org specialreports katrina cfm MIT s Robert Korty a scientist specializing in climate and hurricanes wrote a short article http grist org comments soapbox 2005 09 07 korty index html 87 Lynn Vincentnathan says 8 Sep 2005 at 5 29 PM RE 84 86 as mentioned before while natural causes may go into creating the largest part of hurricane intensity we have to figure GW s part as an add on at the upper level and it is that last bit of intensity that might do the most damage more than the first incrememts assuming the hurricane make landfall in a populated built area So while GW s part may be small its effects could be very large I think that should be more our focus from a policy standpoint than GW s part in hurricanes is small and its effects may be negligible As Roger points out there are many other even better reasons for reducing GW However I think we can add reducing hurricane intensity to our list even if it doesn t have as much results as in reducing other GW effects I m thinking of droughts in Africa glacier melt in the Himalayas which could put 40 of Chinese South Asians at severe water shortage risk no water to drink much less to irrigat crops I can see the problem If we focus solely on hurricanes and not the entire list of effects we might lose some of the intensity in our pleas to get people to reduce GHGs And some people even get confused and bored with the long list of GW harms which just keeps getting longer 88 Eli Rabett says 8 Sep 2005 at 7 55 PM Dear Michael NO Why Because the first order cause of hurricanes is temperature differences between the surface and the upper atmosphere My experience over 30 years of work in the natural sciences and the unnatural engineering is that balancing becomes important ONLY for secondary issues The reason is that if you have an major cause it takes a whole lot of secondary effects all going in one direction to restore the balance Mostly the secondary effects go in both directions and balance themselves out A good example is how the climate sensitivity to 2x greenhouse gas forcing has remained pretty much the same with pretty much the same variation between estimates for a whole lot of years model sophistication and generations of Moore s law In a lot of ways your argument is like the student who shows up before the final with a passel of F s on tests and asks if they can get an A in the course The stars would have to align the second coming be announced and then maybe A good reason why it is dangerous to take up your argument is that it is equally likely that the secondary causes go against you Plan for the worst Pray for the best Don t trust economists They have no clue about assigning costs 89 Steve Latham says 8 Sep 2005 at 9 20 PM Re 81 88 I think you two actually agree One thing I was told in no uncertain terms in an undergrad conservation biology course was that analogies are very dangerous when you want to explain science in a politically charged realm The analogy breaks down and people tend to focus on parts that really aren t most relevant to the point being made For example who says that driving a long time was the main contributor to falling asleep maybe it s the engine sound at 70 or some other thing But I enjoy analogies and I think Michael s was very persuasive in suggesting that going back and looking at what damage hurricanes like Katrina would have done without AGW or with more is an exercise that could be done for interests sake only knowing with any certainty would require a lot more information I d say an impossible amount about how AGW affected other aspects of the storm On average higher windspeed bad but what was proposed was not to look at things on average but to look at a specific case I don t know if things could have been much worse than they were with Katrina but if they could not then it s quite possible that more AGW would have lessened the damage done if not the inherent destructive force Disagreeing with the forensic approach does not necessitate an attitude against assigning blame in general or against policy prescriptions to deal with future likely impacts so I don t think Michael was advocating that people plan for the best I ll stop putting words at your mouths now 90 wayne davidson says 8 Sep 2005 at 10 03 PM Re 85 Thanks for the paper Since hurricane paths don t always hit the same city having an identical population likewise buildings and economic infrastructure it is incorrect to make hurricane financial impact assessments while looking at a long time spans an analysis without nearly identical landfall scenarios doesn t mean much However if you shorten the time span compare it with nearly identical demographics at landfall you may find a better trend aside from the grass talked about above Forecasting future hurricane impacts is done with clarity provided in Hurricane historical met records as proposed at the top of this page Intensity is a key issue which will continue to increase along with GW however Cat 3 4 5 hurricanes typhoons are not confined to landfalls but intensity with a few other met parameters readily show the impact of GW as showed above It is perhaps a matter of time before someone demonstrates a clear and proper hurricane destruction cost comparison I wonder if it is possible given very significant temporal urban demographic disparities 91 Roger Pielke Jr says 8 Sep 2005 at 10 34 PM Re 82 Stefan As much as I like to engage in abstract philosphical arguments about dice they are unnecessary when we have a good quantitative scientifically rigorous empirically based literature on climate impacts Some points to ponder and literature to consider 1 The same hurricane damage database that is too small a sample to show a correlation with the Atlantic basin annual total PDI is perfectly able to show a very strong statistical relationship with another climate index the annual ASO Nino 3 4 temperature anomaly index See this paper Katz R W 2002 Stochastic modeling of hurricane damage Journal of Applied Meteorology 41 754 762 http www isse ucar edu HP rick damage pdf So why is it that we can see the effects of ENSO in the damage record but not for example the annual Atlantic basin total PDI given the exact same randomness in impacts Perhaps one index has a stronger relationship with damage than another no 2 Similarly we have been able to show a statistical relationship between various measures of precipitation and flood damage even though the spatial and temporal area that experience floods are far smaller than the regions over which precipitation is measured We do get the strongest relationships at the basin level of course where precipitation is integrated but we also see a correlation at larger scales See this paper Pielke Jr R A and M W Downton 2000 Precipitation and Damaging Floods Trends in the United States 1932 97 Journal of Climate 13 20 3625 3637 http sciencepolicy colorado edu admin publication files resourse 60 2000 11 pdf Again some metrics have a stronger relationship with damage than others There are good physically based reasons for this 3 Let s completely set aside the issue of trends Emanuel s PDI for the Atlantic basin annual total is not correlated with historical damage The ASO Nino 3 4 index is strongly correlated with historical damage This tells me that the ENSO index is a very good predictor of damage and the PDI simply is not FYI nor is the ACE index used by Gray et al There are however climate indicies that are related to damage such as the decadal AMO see this paper Landsea C L R A Pielke Jr A Mestas Nuà ez and J Knaff 1999 Atlantic Basin Hurricanes Indicies of Climate Changes Climate Change 42 89 129 http sciencepolicy colorado edu admin publication files resourse 76 1999 10 pdf So long as some climate indicies prove to be better than other indicies for explaining historical damage it seems unsatifactory to claim than randomness can explain why one particular index has no correlation with damage A different explanation to consider is that there is in fact not a strong relationship between PDI and damage and projections of future changes in the PDI provide little basis for asserting any effects on damages But these are questions that can resolved through rigorous research e g IPCC WGII type research They won t be resolved through philosphical arguments 92 Heiko Gerhauser says 9 Sep 2005 at 5 06 AM Re 82 To stick to Stefan s example I think Roger would argue that there are other factors we have more control over which would be decisive and statistically detectable such as whether to play the game in the first place not so much settlement in vulnerable areas or whether

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    at about latitude 27 degrees south This was the first hurrican ever reported in the South Atlantic The authors of the report in Geophysical Research Letters state that the hurricane developed because of an unusual combination of high sea surface temperatures low vertical wind shear and strong mid to high latitude blocking which intereferes with normal east west atmospheric flow As a person living on the west coast of Australia at longtitude 33 degree south can anyone offer advice on whether I am more or less likely than in the past to have strong hurricanes we call them cyclones come this far south 116 Tom Rees says 12 Sep 2005 at 6 32 AM Re 97 Roger presumably the losses due to societal changes increased hurricane wind speeds and rising sea levels will interact In order to make a rational judgement you need an estimate of 1 losses with societal changes and no AGW 2 losses from AGW and no societal change and 3 losses with both Then you need to look at the costs of minimizing AGW costs of minimizing these societal changes which are presumably also economically driven versus the benefits which in the case of minimising AGW are generally considered to be much more than simply reducing storm related costs Until such an analysis is available I think that it is pointless conflating these two different issues societal changes vs AGW They are not mutually exclusive after all It is possible to address both simultaneously In fact it may be optimal to do so 117 Pat Neuman says 12 Sep 2005 at 7 31 AM Re 108 Mathias do you think that increases in floods with global warming should be accounted for in developing flood predictions Potential increases as global warming continues are currently being ignored by government agencies See Probabilistic Forecast Updates A Case Study at http www crh noaa gov ncrfc 118 TCO says 12 Sep 2005 at 9 24 AM Why do you cut the comments off I think this is the only thread I can comment on There are interesting ones in the archives and all I wasn t here then when they were open Has Steve been here Did you let him comment Is there a policy that even if germane to the topic of discussion one can not link to anti webpages Response Comments are cut off to prevent spam and since people tend to only read recent posts No one is barred from commenting but comments are moderated for relevance and tone If you have comments related to the topic of this post please continue to comment Future postings may be more to your taste gavin 119 Roger Pielke Jr says 12 Sep 2005 at 9 46 AM Re 116 Tom Good points Here you go Note yes the paper below is in that politically incorrect outlet Energy and Environment which is unfortunate because the paper is solid Those interested in substance will read it for its merits Those interested in avoiding the issues can dismiss the paper because of its venue A Climate Policy for the Short and Medium Term Stabilization or Adaptation Author Goklany Indur M Source Energy Environment Volume 16 Numbers 3 4 July 2005 pp 667 680 14 Abstract An evaluation of analyses sponsored by the predecessor to the U K Department for Environment Food and Rural Affairs DEFRA of the global impacts of climate change under various mitigation scenarios including CO2 stabilization at 550 and 750 ppm coupled with an examination of the relative costs associated with different schemes to either mitigate climate change or reduce vulnerability to various climate sensitive hazards namely malaria hunger water shortage coastal flooding and losses of global forests and coastal wetlands indicates that at least for the next few decades risks and or threats associated with these hazards would be lowered much more effectively and economically by reducing current and future vulnerability to those hazards rather than through stabilization Accordingly over the next few decades the focus of climate policy should be to a broadly advance sustainable development particularly in developing countries since that would generally enhance their adaptive capacity to cope with numerous problems that currently beset them including climate sensitive problems b reduce vulnerabilities to climate sensitive problems that are urgent today and might be exacerbated by future climate change and c implement no regret emission reduction measures while at the same time striving to expand the universe of such measures through research and development of cleaner and more affordable technologies Such a policy would help solve current urgent problems facing humanity while preparing it to face future problems that might be caused by climate change 120 Tom Rees says 12 Sep 2005 at 10 26 AM Thanks Roger unfortunately the abstract is a bit low on detail and I can t access the paper itself However one obvious fly in the ointment is this line indicates that at least for the next few decades risks and or threats associated with these hazards would be lowered much more effectively and economically by reducing current and future vulnerability to those hazards I don t doubt that if your horizon is limited to the next few decades there s little point in attempting to reduce current GHG emissions Reducing GHG is a long term project that at best hopes to achieve stabilization within 50 years What would be useful is an estimate of the relative cost effectiveness in say 2030 and 2080 That would show how the relative importance shifts according to the time horizon Furthermore I don t see any indication in the abstract of a test for the interaction of factors For example in your paper you ascribe the increased costs of storm damage primarily to increased population density and property By projecting these changes into the future with a 50 yr time horizon which again is probably a bit short you predict that the costs due to AGW will be small compared with the costs due to population changes You use this result to downplay the importance of emissions reductions However if more and more people are going to live on the coasts then that will in fact make the need to tackle AGW greater not lesser Furthermore most authors present a false dichomtomy Both actions can be undertaken The question is Will each action be cost effective Not Is one action more cost effective than the other One other lesson from Katrina is that adapdation may not be as effective as many pundits propose After all the inundation of New Orleans was the one natural disaster that everyone saw coming And yet even in one of the wealthiest nations on earth the defences were inadequate and the response plan poor This isn t a criticism of the federal state govts more a criticism of human nature How much more difficult will it be for developing countries to pre emtively adapt to a novel environmental situation 121 Mark Bahner says 12 Sep 2005 at 12 50 PM I wrote According to Jesse Ausubel at Rockefeller University we re ALREADY decarbonizing the global energy system at a rate that will essentially eliminate carbon dioxide emissions by the end of this century Tom Fiddaman replied Ausubel makes no such claim Well you ll have to take that up with Dr Ausubel or William K Stevens of the New York Times Here is what Stevens wrote in the October 30 1999 issue of the Times note the Solstice environmental website places the date of the article as October 31 1999 However that may turn out the decarbonization of the energy system is the single most important fact to emerge from the last 20 years of analysis of the system said Dr Jesse H Ausubel an expert on energy and climate at Rockefeller University in New York City Dr Ausubel predicts that this evolution will produce a carbon free energy system by the end of the 21st century http www2 sunysuffolk edu westn carbon1 html Dr Ausubel predicts that this evolution will produce a carbon free energy system by the end of the 21st century So says the New York Times Tim Riddaman concludes If you want to see technology unleashed on decarbonization try putting a value on carbon Technology is already being unleashed on decarbonization Tom That was my very point The world wide trend towards decarbonization has been going on for almost 200 years It started long before any government was ever worried about global warming It s not going to stop if governments start paying attention to more important problems e g making sure that no strong hurricanes hit any country By the end of this century even a business as usual scenario puts CO2 emissions near zero or at least to the point where atmospheric CO2 concentrations are no longer rising In that NY Times article Jesse Ausubel predicts that the peak atmospheric CO2 concentration will be 500 ppm in 2100 That is very close to my own prediction of approximately 560 ppm http markbahner typepad com random thoughts 2005 01 prujections ipc html The current concentration is about 380 ppm So we have Jesse Ausubel s peak projection of 500 ppm by 2100 and my peak projection of approximately 560 ppm by 2100 My question for Dr Pielke and you and anyone else remains if y all accept Dr Ausubel s and my projections why is it that we should be taking more effective actions to decarbonize the global energy system What benefit would be achieved by limiting the peak CO2 concentration not to 500 560 ppm business as usual values but instead to 450 or 480 ppm This contrasts very strongly with for example limiting black carbon emissions e g from diesel vehicles and residential coal and wood stoves Black carbon aka soot kills Mark Bahner environmental engineer 122 Richard Wesley says 12 Sep 2005 at 2 01 PM First off I want to thank the RC crew for their wonderful site It is definitely one of the most informative sites on the web and the discussions are also of a high calibre It gives me some hope for the future I thought the readers might be interested in a page I put up documenting how I managed to reproduce Emanuel s results for the North Atlantic using the data from National Hurricane Center also referenced by RealClimate and on the page itself For the impatient the plot is here and the entire summary can be found here The pages also includes a few plots I did of hurricane activity for various seasons including the 2004 season Incidentally we are looking for beta testers for the product used to generate the plots so if anyone is interested especially if they have a big pile of data they are trying to look at please contact me at hawkfish at tableausoftware dot com Anyway before I go let me just add that I really appreciate that other scientists like Roger Pielke Jr join in the conversation here it really adds to the quality of the presentations 123 Paul Emberger says 12 Sep 2005 at 4 43 PM Although there is not universal agreement in the scientific community on the global warming and its anthropogenic causes the political community seems to have accepted it and proposed solutions My concern is the solutions themselves For example if we replace significant numbers of internal combustion engines with fuel cells then we trade carbon dioxide emmisions for water vapor What is the effect of increasing the propoprtion of water vapor in the atmosphere Is is better or worse than CO2 in terms of the effect on climate Likewise what is the impact of diverting significant energy from surface winds with massive wind farms While we are clearly getting a better handle on climate study it is not clear that we know enough to start making changes we do not understand or have at least evaluated Response You want http www realclimate org index php p 142 at least for a start William 124 Isaac Held says 12 Sep 2005 at 4 58 PM Continuing my cautionary remarks about overemphasizing the role of SSTs vs upper level temperatures in this issue a useful reference is Shen Weixing Tuleya Robert E Ginis Isaac A Sensitivity Study of the Thermodynamic Environment on GFDL Model Hurricane Intensity Implications for Global Warming Journal of Climate 2000 13 109 121 Part of the abstract reads The results indicate that stabilization in the environmental atmosphere and sea surface temperature SST increase cause opposing effects on hurricane intensity The offsetting relationship between the effects of atmospheric stability increase decrease and SST increase decrease is monotonic and systematic in the parameter space This implies that hurricane intensity increase due to a possible global warming associated with increased CO2 is considerably smaller than that expected from warming of the oceanic waters alone I am harping on this point becuase i see it a central to an informed discussion of the relative ability of internal Atlantic SST variations and global warming to affect hurricane intensity an internally generated increase in Atlantic SST is likely to be associated with a more unstable atmosphere than the same increase due to global warming 125 Steve Bloom says 12 Sep 2005 at 10 53 PM Re 120 Five years is a long time in climate science I think http www gfdl noaa gov reference bibliography 2004 tk0401 pdf Knutson Tuleya 2004 cited in the post and the source of the first graph is more reflective of current thinking Note that it uses an ensemble of models as contrasted to the single one used in the study you cited You can use Google Scholar to try to check if a paper is still entirely current Unfortunately sometimes it s a bit hard to figure out if this is the case or not since often the terms of rejection of the prior work are subtle 126 Lynn Vincentnathan says 12 Sep 2005 at 11 27 PM RE 118 I see no problem with your suggestions I hope you are aware of Amory Lovins s works such as NATURAL CAPITALISM and works of other such experts businesses that have actual examples of greatly reducing GHGs in cost effective ways As I ve mentioned I m just waiting for a plug in hybrid then I can drive almost entirely on wind power and probably at a cheaper price I think that building stronger buildings higher levees actually costs more but will be worth it in the long run if destruction from hazards is mitigated On other hand we can also build using green products like reused wood and natural pozzalons in cement or planning room building sizes to available materials without much wastage and using passive solar other energy resource efficient conservative techniques products If we have to rebuild let s do it right this time with awareness of most likely to worse case GW scenarios It seems the science keeps racheting up predictions of GW harms as time goes on compare FAR SAR TAR the one coming up We ve got to be aware of what way the wind it blowing I think congress wanting to open up more oil drilling in the Gulf of Mexico is very unwise considering we are entering a period of greater natural hurricane activity plus the overlay of GW enhancement perhaps even category 6 sometime in the future Maybe they really do not know about GW 127 Roger Pielke Jr says 12 Sep 2005 at 11 44 PM Re Response to 97 Stefan Thanks for your continued comments and my apologies if you interpret condescension and insinuations none are intended I will admit to pushing you to engage this discussion in the context of a robust literature on climate impacts That literature does suggest some answers and raise some further questions Most importantly to your latest point how does one explain the fact that the same hurricane damage record shows a clear and statistically significant ENSO signal in relation to ASO Nino 3 4 shows absolutely no correlation with the Atlantic annual PDI This question must be addressed satisfactorily before asserting a future relationship of PDI and damage And until the PDI is shown to be a metric of destuctiveness forward looking statements about the relationship of changes in the PDI to changes in damage remain purely speculative FYI as interesting as this thread has been it is becoming a bit difficult to follow Perhaps you might revisit this subject when Webster et al comes out later this week which will have a little something for everyone 128 Matthias Brun says 13 Sep 2005 at 8 00 AM RE 117 Pat Flooding is definitely an issue in Europe and also Landslides an avalanches once you get to steeper terrain In Switzerland every community has to develop a map of natural hazards which is relevant for buildung actions So if you want to build a new house on the wrong slope you are either not allowed or you have to get further inquieries I work in an office for natural hazards and I can tell you we got a lot of work right now because of the recent flooding event here In certain areas boulder of 15 feet in diameters where transported in small riverbeds and you can imagine the damage to the houses The events we got in some place were a lot bigger than the 300 year incidents we calculated our hazard maps with So as you can figure out easely the statistics have to be rewritten or don t work anymore under the changing climate Extrapolation and modelling of rainfall events is all you can do and the picture doesn t look good All you can do is abandon some of the dangerous areas in the moutains or along the rivers not very easy in the highly populated alpine regions in Europe Same problem for New Orleans Climatic change is taken as a fact in Europe And I still think the discussion should be on values and human duties for gonverments and everyone and how to attain the inescapable post fossil society instead of technical and security measures because that is closing the eyes to origin of the problem 129 Tom Rees says 13 Sep 2005 at 10 45 AM Re 127 Roger you ask how does one explain the fact that the same hurricane damage record shows a clear and statistically significant ENSO signal in relation to ASO Nino 3 4 Have you ruled out the possibility that ENSO changes the storm track such that it is correlated with the proportion of landfalling storms as well as hurricane intensity If this were so then it would explain why it is a better correlate of economic loss than storm intensity alone I have skimmed your paper but can t see where this issue is addressed 130 Joel Shore says 13 Sep 2005 at 12 05 PM Re 123 1 While it may be true that there is no universal agreement in the sense of complete unanimity in the scientific community on global warming there technically isn t that on evolutionary theory or just about anything else There is a general concensus and while uncertainties remain I think that at least here in the U S the politicians are actually well behind the scientists not ahead of them in their acceptance of the science and willingness to act on it 2 As you can find discussed in a previous post here on RealClimate direct anthropogenic emissions of water vapor are basically a red herring in the context of global climate change First of all fossil fuels are hydrocarbons and hydrocarbons contain hydrogen that gets converted to water vapor upon combustion so our current fossil fuel burning is already producing plenty of water vapor Second of all humans can t easily have nearly as significant effect on water vapor in the atmosphere as carbon dioxide by direct emissions of these gases This is because the time scales for the gases to remain in the atmosphere are much different A CO2 perturbation lasts on the order of a hundred years or more while water vapor gets rained out in about a week It is also because there is much more water vapor in the atmosphere than CO2 and since the amount of climate forcing goes approximately logarithmically with concentration that means the concentration of water vapor has to change by a significantly larger ABSOLUTE amount to produce the same effect Admittedly a given FRACTIONAL change in water vapor concentration is more potent than the same FRACTIONAL change in CO2 concentration but this difference is not large enough to offset the larger difference due to their relative concentrations in the atmosphere Where water vapor is important is as a feedback effect whereby the warming of the atmosphere due to increased CO2 causes the equilibrium concentration of water vapor to increase and this then enhances the warming because of water vapor s absorption of infrared radiation 3 Without having done the calculation or seen it done I would conjecture that your concerns about wind are another red herring The amount of wind farms needed to extract a noticeable amount of the total energy available from the wind would probably be huge Furthermore the perturbation to the winds that we cause with wind farms will at least for quite some time likely be smaller than the perturbations just due to other structures that we have built buildings etc 131 Roger Pielke Jr says 13 Sep 2005 at 12 38 PM Re 129 Tom Thanks Actually this paper is more directly relevant Pielke Jr R A and C W Landsea 1999 La Nina El Nino and Atlantic Hurricane Damages in the United States Bulletin of the American Meteorological Society 80 10 2027 2033 http sciencepolicy colorado edu admin publication files resourse 85 1999 14 pdf We do find that the ASO Nino 3 4 index is related independently to both frequency and intensity With respect to the latter we find that a 20 difference in intenstity 36 3 m s vs 30 6 m s average winds between the two phases manifests itself in twice the losses per storm during La Nina than in El Nino and we can see this effect in the seasonal totals So yes we can identify the changes in the damage record related to intensity that are considerably smaller than those identified in the PDI Rick Katz quantified these effects more rigorously in this paper Katz R W 2002 Stochastic modeling of hurricane damage Journal of Applied Meteorology 41 754 762 http www isse ucar edu HP rick damage pdf Response Just a clarification a 20 increase in wind speed as cited above corresponds to a 73 increase in the cubed wind speed The PDI is the cubed wind speed integrated over surface area and life time of a hurricane If size and life time of hurricanes increase as well with increasing mean wind speed then the PDI will increase more than 73 for a 20 increase in wind speed What I conclude from this A doubling in losses for a 20 wind speed increase seems consistent with losses being proportional to the PDI You don t know whether the ENSO related changes in hurricane power that you can identify are indeed considerably smaller rather they are similar in magnitue to the changes that Kerry talks about stefan 132 Roger Pielke Jr says 13 Sep 2005 at 4 16 PM Re 131 Stefan Let s assume that you are correct that the ENSO related and PDI related effects on TC power are of similar magnitude but do note that Emanuel uses max winds and I referred to mean winds The question remains if this is the case why do we see a very strong ENSO signal and no PDI signal in the damage record Response This is just two bits of speculation on my part but it is conceivable that a the influence of ENSO is of a different character than the influence from SST i e there is more happening than a similar increase in hurricane intensity number and ii the different frequency distribution of ENSO events compared to variations in SST or PDI mean that the signal is stronger compared to the noise in that frequency band i e the SST influence maybe harder to discern in the data because of the coastal development contamination which clearly dominates the longer timescale changes gavin 133 Steve Bloom says 13 Sep 2005 at 5 39 PM A quick Google Scholar finds http garnet fsu edu jelsner PDF Research Elsner2003 pdf If this paper is correct the upshot is that ENSO does have a major impact on tracking of hurricanes and thus on the damage they do Interestingly there s a related paper showing that ENSO does the same thing on the other side of the planet with East Pacific typhoons that s one dominant cycle I think Emanuel addressed why it might be a long time 50 years before any connection between PDI and damage would become apparent 134 Steve Bloom says 13 Sep 2005 at 6 22 PM From Emanuel s FAQ 7 Q Does this increase in PDI mean that we are seeing more hurricane caused damage in the U S and elsewhere A There is a huge upward trend in hurricane damage in the U S but all or almost all of this is due to increasing coastal population and building in hurricane prone areas When this increase in population and wealth is accounted for there is no discernible trend left in the hurricane damage data Nor would we expect to see any in spite of the increase in global hurricane power The reason is a simple matter of statistics There are far too few hurricane landfalls to be able to discern any trend Consider that up until Katrina Hurricane Andrew was the costliest hurricane in U S history But it occurred in an inactive year there were only 7 hurricanes and tropical storms Data on U S landfalling storms is only about 2 tenths of one percent of data we have on global hurricanes over their whole lifetimes Thus while we can already detect trends in data for global hurricane activity considering the whole life of each storm we estimate that it would take at least another 50 years to detect any long term trend in U S landfalling hurricane statistics so powerful is the role of chance in these numbers 135 Roger Pielke Jr says 13 Sep 2005 at 6 41 PM Re 132 and 134 Gavin The data has been adjusted to remove any development signal But I do lean toward a view that the relationship is weak for whatever reason and there are good ones why this might be so Steve My question seeks to address how Kerry s explanation can be correct yet we still can identify and ENSO signal in the database There only only a few possibilities and Kerry s simply reinforces the argument that the PDI is only weakly if at all related to damages Response Detecting a trend and detecting an oscillatory signal of the same magnitude in the same noisy data set are not the same thing I suspect finding the oscillatory signal is easier This would be easy to check for anyone with a couple of hours time at their disposal unfortunately that s not me right now Cheers Stefan 136 Pat Neuman says 13 Sep 2005 at 10 14 PM Re 128 Hi Matthias there s a commentary on the overtopping of dikes in New Orleans and Grand Forks at http www startribune com stories 562 5610904 html and at http groups yahoo com group ClimateArchive Flood prediction preparedness and design of structures with a rapidly warming world interests me If you want to talk more I suggest you join http groups yahoo com group ClimateArchiveDiscussion 137 Steve Bloom says 14 Sep 2005 at 2 46 AM Roger Stefan among others has already responded to the same issue in comments 49 73 and 82 in considerable detail The key point seems to be that ENSO affects tracking and PDI does not According to the paper I linked ENSO results in more straight moving hurricanes that track through the Caribbean and Gulf before landfalling This seems to me to be a very large effect since pretty much all of those hurricanes landfall many of them in the US plus I assume they tend to be a lot stronger when they do so since they spend more time over warmer waters Stefan s view is that PDI could already be having a substantial but still undetectable influence so perhaps it would be worth looking at how strong of a signal could exist now and remain undetectable I assume that this must be the calculation Emanuel did in coming up with that 50 year number Would it help resolve things to have that 138 Tom Rees says 14 Sep 2005 at 7 19 AM The Association of British Insurers use an Insurance Catastrophe Model to estimate that a 6 increase in hurricane wind speeds will increase the annual insured losses by 3 9 billion in the US and 1 6 billion in Japan 2004 For a 1 in 100 year storms the cost will be an extra 41 billion in the USA This assumes that there are no changes in demographics precipitation storm surges or adaptation They point out that on the one hand higher insurance premium will encourage more risk conscious development but that on the other hand increases in precipitation and storm surge height are also likely and will inflate the figure I know insurers have an incentive to talk up risks but they don t have an incentive to talk up risks due to climate change compared with other risks In this regard this Sept 8 report coauthored by a paid up scientist from LLNL is interesting Availability and Affordability of Insurance Under Climate Change They quote one of your papers Roger One can easily hypothesize that increasing population and urbanization in the United States has led to a commensurate increase in population at risk Yet one can also hypothesize that the various societal responses may have more than compensated for population growth and in fact fewer people are today at risk 139 Roger Pielke Jr says 14 Sep 2005 at 8 05 AM Re 137 Steve Thanks We do find an independent intensity effect in the ENSO results so we can simply ignore the frequency effects for present purposes and the question remains Emanuel s analysis suggests that PDI is not at all a good proxy for damages i e there is historically no relationship with damages and in the future this relationship will continue to be weak Another way to think about it is that the PDI includes a whole lot of information not relevant to hurricane landfalls so of course the relationship to damage is weak The ENSO analysis helps us to understand what magnitude of climate signals might be observed in the damage record via a simple climate index What this suggests to me is that climate scientists should continue to develop indicies of hurricane behavior but to use as one criterion for their development a close correlation with damages Emanuel s work is an important step in this direction but I d bet we can improve upon it We have discussed using V 3 at landfall as such an index but it is not well correlated with the annual basin PDI The ACE index is similarly poorly correlated with damages But let s keep looking the search really has just begun There is no need to force the PDI to carry more significance than the data allow there are going to be better indicies from the standpoint of understanding the relationship of climate changes and damages 140 Tom Rees says 14 Sep 2005 at 10 19 AM Re 137 Roger are you really saying that when a hurricane hits land there s no relationship between PDI and likely destructiveness I presume not After all we know that a mean 20 increase in wind speed in La nina years gives a doubling of damage per hurricane Pielke Landsea 1999 141 Dan Allan says 14 Sep 2005 at 10 57 AM The debate here has focussed on two issues 1 correlation between SST and hurricane strength PDI 2 correlation between PDI and damage Obviously both of these correlations need to exist to conclude that AGW will lead to increased hurricane damae Regarding the 1st point I admit that like most of the rest of us I am not an expert on hurricane formation But it seems quite clear empirically that the SST correlates much more closely with hurricane strength than does temperature gradient instability For instance it is well known that hurricanes require SSTs of 80 degrees F to form Period This is the minimum There is no exception in the case of a very high degree of instability or very low shear or whatever where a hurricane will form with a SST of 76 degrees F It simply doesn t happen Moreover each category of storm has a similar minimal SST under which it will form I wish I had a link for this but I can tell you that I have read enough hurricane forecast discussions to feel certain of what I am saying This suggests to me personally that a correlation between AGW and hurricane strength PDI is highly likely unless someone can show an additional likely effect of AGW that is so strong that it cancels this factor out entirely Regarding the second point In some cases it seems to me that the argument in favor of a correlation is so strong that if we don t see a correlation historically we have to simply wonder if there is enough data yet to see the correlation if we are asking the right questions if there is so much background noise that it masks why is potentially a very significant correlation or some combination thereof I think this is just such a case The issue of how we pose the question seems especially pertinent here Unless I misunderstood Roger is looking at total annual PDI versus annual damage rather than each storm s PDI versus that storm s damage To me this is likely to obscure correlations with lots of noise Suppose we wanted to test the correlation between pitching velocity and strikeout potential Would we look at the net average velocity across all pitchers in year A and compare it to total strikeouts Or would we look at the average velocity of each pitcher and compare it to that pitcher s strikeouts To me the first method has a great deal of noise inherent in it Finally if Katrina really causes 200 billion in damage and given that it was strong storm in a year of strong storms it is likely to bring out a correlation between PDI and damage that had not previously been evident And the fact that a single event could do this assuming it does do this is just an indication of how few data points we have 142 Tom Fiddaman says 14 Sep 2005 at 1 23 PM Re 119 A Climate Policy for the Short and Medium Term Stabilization or Adaptation I don t have the journal but assume the article is similar to this one by Goklany Reducing Climate Sensitive Risks in the Medium Term Stabilisation or Adaptation I agree with some of Goklany s observations e g if you want to stop malaria tackle it directly not via climate However in other ways it s shaky including those observed by Tom Rees 120 the false dichotomy short horizon interactions Pielke writes There are much much better ways to deal with the threat

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