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  • Sommes nous sûrs qu’il faisait plus chaud il y a 6000 ans ? « RealClimate
    Adirondack Weather 4 Roger Jones says 31 Dec 2004 at 8 41 PM Good work on the site Following is an Antipodean perspective on palaeoclimatic reconstructions The emphasis on northern hemisphere palaeoclimate records as representing a global record is very problematic for those of us who live and work in the rest of the world In southern Australia the period 6 8 ka thousand years before present crater lakes that now show falling water levels were overflowing Reconstructions of climate indicate that the lake evaporation rainfall ration was above 1 and could hve been greater than 1 2 Palaeoclimates 3 51â 82 The current ratio in the region is about 0 8 If temperatures and solar radiation were at current levels at 6 8 ka this would require rainfall at 150 above today s volumes It is therefore likely that the climate at that time was cooler particularly in summer though the cloudy winters may have been warmer suggesting a more uniform seasonal cycle suppressing evaporation Rainfall was certainly higher at that time An abrupt shift at about 5 5 ka saw some 2 000 years of sustained drying In northern Australia at around 6 7 ka eastern Queensland reconstructions indicate warmer and drier conditions in southern Queensland and warmer and wetter conditions in the north www dsm unile it Bacheca IGCP437FinalConference AbstractBook Grindrod119 122 pdf the former from one site and the latter from multiple sites At that time animals in the montane tropics were restricted in their distribution due to higher temperatures suggesting that similar restrictions may occur under global warming Proceedings of the Royal Society Biological Sciences 270 1887 1892 track back through refs for palaeo work The past 200 years of land use change in Australia has compromised most hydrological proxies making reconstruction difficult We still don t have a good idea of what was going on in the Holocene in Australia but words like optimum developed to describe conditions in the cooler regions of the northern hemisphere confuse when applied globally Note also in reference to the climate of the past 2000 years south eastern Australia was relatively cool and wet until about the mid 19th century Journal of Hydrology 246 158 179 It is now as dry in the region as it was in the early Holocene and drier than it has been for most of the Holocene These changes precede the enhanced greenhouse effect If changes in rainfall projected by climate models occur it could become as dry in southern Australia as it was about 12 5 ka before present Simple pictures of how Earth s climate has behaved in the past rarely stand up to regional scrutiny We should not jump to the conclusion that largely northern hemisphere reconstructions show some kind of globally homogenised picture Palaeoclimatic reconstructions are sorely needed from the three southern continents Africa South America and Australia and from southern islands the latter mentioned to keep our Kiwi and Pacific friends happy 5 Understanding Global Warming Understanding Global

    Original URL path: http://www.realclimate.org/index.php?p=65 (2016-02-13)
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  • Voici pourquoi rechercher le réchauffement global dans les océans est pertinent « RealClimate
    The conservative Heritage Foundation asked why the about face The change in policy is only cosmetic This is again another rhetoric technique You make a small change to change your public image but the change is only a surface change You make yourself look good by seemingly embracing a position or policy that you disagree with but it is only a token effort and you really don t accept the position or policy The goal is to calm down or stop your opponents by making them think they have won without actually giving in to them The President has a negative public image in environmental policy By apparently accepting climate change science he is trying to improve his image as an environmental president But there is no substantive change in the climate change policy The environmentalist community uses the word greenwashing to describe such a tactic Look at the current climate change materials on the EPA website The main theme is that there is climate change but there is so much uncertainty about the science Conservative think tanks take a very similar position For example on the EPA site Figuring out to WHAT EXTENT the human induced accumulation of greenhouse gases since pre industrial times is responsible for the global warming trend IS NOT EASY This is Because OF OTHER FACTORS both NATURAL and human affect our planet s temperature SCIENTIFIC UNDERSTANDING of these OTHER FACTORS â MOST NOTABLY NATURAL climatic variations changes in the sun s energy and the cooling effects of pollutant aerosols â REMAINS INCOMPLETE The language used emphasizes uncertainty The EPA continues Nevertheless the Intergovernmental Panel on Climate Change IPCC stated there was a discernible human influence on climate and that the observed warming trend is unlikely to be entirely natural in origin In the most recent Third Assessment Report 2001 IPCC wrote There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities This section is trying to cast doubt on the IPCC report one of the most comprehensive climate change studies The term nevertheless is used to imply that the IPCC conclusions are going beyond or contrary to what is scientifically known and this section uses quotation marks around discernible unlikely to be entirely natural in origin and There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities to make key IPCC conclusions seem questionable The current White House climate change policy is continued research but not any action Regardless of what the White House proclaims in public sound bites it still questions the basic climate science 15 Grundt says 24 Feb 2005 at 8 58 PM Re 12 It is amazing for me to learn about the overwhelmingly high heat gain of oceans compared to the other components This paper helps very much to understand how important is to think well before jumping with any conclusion Thank you 16 dave says 24 Feb 2005 at 10 46 PM Re Warming in the Pipeline From Hansen et al 2002 It is also inferred that the planet is now out of radiation balance by 0 5 to 1 W m2 and that additional global warming of about 0 5 C is already in the pipeline I have always been a bit baffled by the physical processes involved here This is an important subject which is not widely and clearly understood by non scientists like me Yet it is a crucial finding and I believe that many people including environmentalists and policy advocates do not understand its implications Is there some simple intuitive explanation of how this pipeline warming is estimated with respect to an equilibrium climate sensitivity at a doubling of CO2 equivalent thus including methane ozone aerosols CFCs How and at what point do the oceans come into heat balance Don t the oceans have to absorb heat not only in the surface mid layers but right down to the bottom for radiative heat balance to occur And isn t that a process that takes hundreds to thousands of years If I ve asked a poorly formulated question and missed some basic assumptions that s OK Still the gist of what I m trying to find out remains And I think others could benefit from understanding this important result Response A big part of the response to any radiative forcing is what happens to sea surface temperatures since they control most of the feedbacks that are important in the equilibirium response The presence of the radiaitve imbalance at the top of the atmosphere is an indication that the sea surface has not warmed up sufficiently to match the forcing This is because as you note deeper layers of the ocean are also heating up However this is a slow process and the sea surface will come close to equilibrium with the forcing in around 30 to 50 years It is because the deep ocean adjusts so slowly that the long term remaining imbalance will be small and barely noticeable in the surface temperature data Given an actual imbalance you can estimate how much further the sea surface will need to warm to remove it this is the warming in the pipeline The number comes from using the climate sensitivity say 3 1 C so if the imbalance is 0 7 W m2 you might expect 0 5 C of additional warming eventually Most of that however will come within a few decades gavin 17 Tom Huntington says 25 Feb 2005 at 3 57 PM I have a question for the experts at RealClimate From Levitus et al 2005 GRL cited in the initial posting above Figure 1 there appears to be a loss of about 4 X 10 22 J in ocean heat content from about 1979 to 1987 Where did this vast amount of heat go Looking at Levitus et al 2005 Figure 3 no other heat sink can account for such a large flux Did it go back out into space through the top of the atmosphere If a significant fraction of this heat lost from the ocean went into the atmosphere one might have expected the surface air temperature to have increased faster during this period than during the subsequent period of the 1990s when the ocean heat content gained 5 X 10 22 J but this is not what was observed see reference Figure 2 7c in the IPCC TAR Working group I 18 Ferdinand Engelbeen says 25 Feb 2005 at 6 29 PM In addition to 17 there is a discrepancy between the modelled inflow of extra heat into the oceans in the 1955 2000 period and the TOA balance which shows a large loss of heat in the 1985 2000 period Based on ocean data and models the extra inflow of heat was calculated to be between 0 2 W m2 Levitus via 0 5 to 0 7 W m2 Hansen for the last decade But at the top of the atmosphere there is an increasing loss of energy in the tropics of 3 W m2 since 1985 according to Chen e a see http pubs giss nasa gov docs 2002 2002 ChenCarlsonD pdf As that is in the 30N 30S band that represents 50 of the earth s surface of which a large part is ocean The loss of heat was due to increased Hadley cell circulation resulting in decreased cloud cover The increase in insolation of 2 W m2 from the cloud cover decrease was accompanied by an extra outgoing 5 W m2 heat flow How does that fit in the ocean models Response And yet it warms Two things can be going on here firstly the loss in the tropics may be more than compensated for in the rest of the world which is consistent with the extensive Southern Ocean warming observed by Gille 2002 and secondly the data from the tropics may be less complete or accurate than claimed although I am not aware of any specific reasons why that might be I would therefore go with my first answer gavin 19 dave says 25 Feb 2005 at 11 15 PM Re Latest Levitus et al Finally a link for the full Levitus et al 2005 paper Warming of the world ocean 1955 2003 which I had not been able to read at AGU agu org A noteworthy quote For the Atlantic Pacific and Indian Oceans the increases of heat content linear trends are respectively 7 7 3 3 and 3 5 x 10 22 J As with our previous work it is the Atlantic Ocean that contributes most to the increase in heat content Also if you look at Table T2 in this paper you will see that ocean sea surface heat storage 0 700m from 1955 2003 in W m2 is always higher at northern latitudes than the corresponding southern latitudes in every case even with the extensive Southern Ocean warming as noted by Gavin responding to 18 20 Stephen Berg says 26 Feb 2005 at 9 16 PM Here s a little something I wrote up on a train from Paris to London on a vacation I have a B Sc in physical geography so I am not an expert to the extent of Drs Mann Bradley etc Skeptics often cite volcanism as a cause for climate change and Greenhouse Gas GHG increases It is a cause or a trigger for catastrophic changes over a short term period However it leads primarily to the onset of ice ages or cool periods rather than a warmer period due to volcanic ash that blocks out the sun Since volcanism in long term periods i e decadal and century timespans is relatively constant one would expect GHG fluctuations to be minimal In other words fluctuations in global GHG concentrations are not dependent generally on volcanic events Another aspect of climate change which is often cited and is dealt with in this portion of RealClimate is the temperature of the oceans As the atmosphere warms the ocean must as well since there is a coupling effect between the two ecosystems Skeptics say that submarine volcanism explains the current warming of the oceans However this is completely untrue since over decadal or century long periods such volcanism caused by sea floor spreading and undersea earthquakes remains fairly constant since the rate of sea floor spreading or tectonic activity remains fairly constant This in an unchanged situation i e with no other variables present such as atmospheric temperature fluctuation would result in a relatively constant mean ocean temperature Now since there are variables present GHG concentration atmospheric temperature changes etc the ocean temperature cannot remain constant if it seeks to find equilibrium like all things in nature Therefore this argument by the skeptics is inaccurate and leads to the confusion of the general public due to the disinformation done in the media today 21 Ferdinand Engelbeen says 27 Feb 2005 at 5 03 PM While the distribution of heat over the oceans is a complicated matter due to radiative in output modulated by cloud cover ocean and air currents some more discrepancies arise Greenhouse gases are rather well mixed over both hemispheres but Levitus 2005 points to differences in aerosols between the NH and the SH The influence of aerosols is mostly in the NH were a significant lower warming than over the SH should be visible But that is not the case it is the opposite which happens That is even more striking for the Indian Ocean where the northern part is heavily loaded with aerosols causing 13 2 W m2 less insolation compared to the southern part But both parts are warming at near equal speed Response You are confusing heat content gain with surface air temperature rise They are in fact opposing phenomena SAT in zones of deep ocean mixed layers is expected to warm more slowly than average precisely because the energy is warming the deeper ocean layers instead of the surface While aerosols do play a part in hemispheric differences the biggest difference in the SAT trends is because of the greater expanse of ocean in the SH Moreover if we compare the 9 13 year sun cycle with the global sea surface temperatures SST the variation is app 0 2 0 3 K within a cycle see the bottom graph at NASA That a variation of only 0 1 app 1 3 W m2 TOA in direct sunlight may give such a large variation at the ocean s surface is probably a question of modulation of cloud cover How that translates into real W m2 variation at the sea surface is something the physicist may calculate See further the discussion about sun cycle cloud cover within the comments at http www realclimate org index php p 42 Response A student activity worksheet I have no idea where those numbers come from or what they are based upon The best evidence so far is that there is about a 0 1K cycle in surface tempertures associated with sunspot cycles and that is only detectable once all volcanic and ENSO related activity is substracted out White et al 1997 While there is no recent increase in solar activity the average activity still is much higher now than in the beginning of the 20th century According to different solar reconstructions the average increase in solar activity since the Maunder minimum may have been three times the variation within one cycle Response or as little as one times the solar max min variation It is the quantification of much higher that is at issue here Estimates of the magnitude long term solar changes remain mostly speculative Foukal et al 2004 That solar activity is largely underestimated was a topic at the SORCE meeting last October Widespread empirical evidence from the extensive Earth climate datasets suggests the presence of an 11 year solar signal of order 0 1K in surface atmospheric and ocean temperatures But general circulation models GCMs underestimate this response by as much as a factor of five Response Find a proper reference for the quotation about the GCM results as far as I can tell none of the presentations at that meeting made that claim Thus that greenhouse gases and aerosols are the only dominant factors in recent ocean temperature increases seems to be a little premature Response No one is claiming that GHG aerosols are the only mechanism the claim is that they are the dominant forcings Well mixed GHG are exerting a forcing of around 2 4W m2 more than during the pre industrial At the largest supportable value for long term solar 0 3 it has only contributed 0 6W m2 since the Maunder Minimum It would need to be 8 times that to even equal GHGs Plus over the last 25 years there has been no siginficant change in solar The ocean heat content analysis by Barnett and in other groups show that the changes are most consistent with the GHGs becoming increasingly dominant over this time gavin 22 Ferdinand Engelbeen says 28 Feb 2005 at 9 09 PM Sorry I was comparing heat content not SST neither SAT of different parts of the oceans down to 300 m depth where most of the variation is visible based on the data of Levitus e a which can be downloaded from the NOAA web site If you plot the NH data against the SH data the heat content of both is varying more or less simultaneous with larger amplitude in the SH and the trend is near equal That means that the NH parts of all oceans which have a smaller volume are heating faster than the SH parts As the area volume ratio for the NH parts of the oceans is practically the same as for the SH the surface heating W m2 must be larger in the NH parts within the constraints of heat exchange via ocean and air currents and partly by the difference in warming area in the tropics vs the cooling areas in the higher latitudes While the general heat increase due to GHGs is app 2 4 W m2 since the industrial revolution the global reduction direct and indirect by sulfate aerosols is estimated to be over 1 W m2 see Hansen As most of this is over the NH be it mostly over land this should have a discernable influence on the difference of heat inflow between NH and SH parts of the oceans the other way out than observed I suppose that the NASA doesn t give students any wrong data But while the graph was only for SST sea surface temperature something different of SAT surface air temperature even at sea the influence of the solar cycle and volcanic episodes El Chicon and Pinatubo is visible globally in the oceans until a depth of 300 m in the Levitus data The global amplitude down to 300 m is between 1E 22 and 3E 22 J compared to 4E 22 J for the increase in heat content in the period 1955 2003 note there seems to be a discrepancy in units between the story of Levitus and the data The ENSO and other recurrent phenomenon shouldn t have much influence on the ocean s global heat balance The variation in heat of average 2E 22 J in only one decade for the upper 300 m needs a lot of heat inflow variation at the surface About solar there is certainly an underestimate depending on the model of at least a factor 2 See the optimal coefficient experiments of Stott e a And the sun s magnetic field has risen with a factor 1 4 since 1964 and probably 2 3 since 1901 See Physicsweb While the exact mechanism for the influence of the solar cycle on cloud cover still is not known the influence nevertheless is observed see Kristjánsson

    Original URL path: http://www.realclimate.org/index.php?p=124 (2016-02-13)
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  • Planetary energy imbalance? « RealClimate
    at 8 58 PM The IPCC 100 year temperature change model IPCC AR4 discussed in the article appears to reproduce the 1940 1970 cooling period I have not heard an explanation for this trend before so I wonder if you can tell me what factors caused a cooling in a time of increasing greenhouse gas levels Response The IPCC itself doesn t have any models however the results from the this GISS model have been submitted to the archive run by IPCC so that they can be considered for the next assessment report AR4 With respect to your question the slight cooling trend seen in the results is a function of a combination of increasing aerosols significant volcanic activity especially in the early 1960s and a plateau in both the greenhouse gas forcing and solar Together that produces the blip that you can see Once internal variability is also taken into account the trend goes from near zero to negative over the different realisations gavin 52 John Dodds says 19 May 2005 at 11 14 AM Re 50 Response Beacuse i solar irradiance is not increasing appreciably Where does the Solar Irradiance 0 3 W m2 number in the IPCC GISS 1750 2000 Forcings Bar Chart come from The IPCC chapter on forcings http www grida no climate ipcc tar wg1 fig6 5 htm did identify that for solar irradiance the 1750 2000 DATE is actually 1744 1996 these being the dates for the 11 year cycle bottoms TDoes this mean that any forcing bar chart or table that uses the 0 3 value is actually missing the 1 0 to 1 5 W m2 that is attributable to the 11 year solar cycle value from 1996 to 2000 or 2003 It was also very strange that I could not read anything close to 0 3 or 0 22 off the solar chart given by IPCC My estimate was always over 1 5W m2 perhaps meaning that the solar chart was an 11 year moving average and did not show yearly bottoms Another observation was that if you started in 1700 instead of 1744 then the solar irradiance change was an additional 1 5W m2 larger but CO2 was about the same So is the solar irradiance really 3 0 or 4 0 W m2 the difference from the values from 1364 to 1368 or do you have to include the 11 year cycle values also or is it actually 0 3 or what Just what numbers get used in the computer model the real year over year changes or the ones you show in the forcings table And with such a wide variation just how meaningful is the choice of DATES for the Forcing charts curves It certainly biases the conclusions or inferences taken from the forcing curves Response The only thing that really matters is the long term change because the 11 year cycle is heavily damped by the ocean thermal inertia You are also confusing a change in the solar irradiance i e 0 1 of 1365 W m2 1 3W m2 over a solar cycle to what is on the forcings chart which is the net forcing once you allow for the geometry and albedo effects i e divide by 4 and multiply by 0 7 0 24 W m2 The model runs cited above only used data from 1880 on so the difference between 1700 and 1750 is not relevant I think 1750 was chosen for that graph because the anthropogenic effects are close to zero however solar and volcanic forcing were varying significantly at that time Those variations are small compared to the subsequent 20th century forcings but if you were particularly interested in the 18th and 19th C you would need to be careful about what start dates you used gavin 53 John Dodds says 19 May 2005 at 3 35 PM Re 50 Response part ii Beacuse ii the bigger effect is the reduction in outgoing long wave radiation by increasing GHG concentrations gavin Is the reduction in outgoing long wave radiation represented by the GHG Forcing of 1 5 W m2 in the 1750 2000 Forcing Bar chart If so then just HOW does all this energy get created How is the 1 5W m2 FIVE times larger than the 0 3 W m2 from the solar input It is the solar input energy change the ONLY source of energy change from equilibrium to the earth that causes the greenhouse effect in the first place All airborne gases are totally incapable of creating energy by themselves Doesn t the LAW of conservation of energy apply to Forcing charts Could it be that the Forcing bar chart is an incomplete and very misleading representation of the total energy change process Not only is the forcings chart missing all the energy associated with water vapor feedbacks attributable to GHGs aerosols etc and the energy change in the ocean identified above BUT is it also missing the negative forcing associated with the energy that the GHGs etc emit to space Response I think you are fairly well confused here You appear to think that there should be some relation between the solar radiation variation and the GHG radiative forcing There isn t The GHG forcing can be positive while the solar var could be negative What you need to do is throw away whatever concept of radiative forcing you are using and use the one which the chart was prepared with ie http www grida no climate ipcc tar wg1 214 htm William If the forcings chart is missing all these components then how can it be used to conclude that GHGs are bigger than solar in driving the global climate change It only looks at part of the picture I go back to the original 50 question Why isn t it that the SUN solar input energy is driving the climate and since it has been increasing Response Because the recent changes in solar output have been small and don t fit the temperature record at all well http www grida no climate ipcc tar wg1 244 htm 61111 William then why should we not expect the earth air and water to increase in temperature until a new equilibrium is reached AND the corollary when the solar input decreases would we not expect the temerature to go down as it did in 1999 2000 and 1940 70 and 1400 thru 1700 and all the other times in spite of the increasing CO2 After all this is what happens every single day CO2 in the air is just another gas It has a slightly bigger heat CAPACITY most of which is not used than the O2 and N2 that it would REPLACE in the air BUT the total energy dictated by the Solar input will just be redistributed slightly more into CO2 H20 less into O2 and N2 but they all go up if there is a net increase in energy The energy content of the air and water will still go up and down with the solar input The sun is causing global warming Please note that the conclusion above in no way casts doubt on the fact that the temperature hockey stick exists that the air is warming that the ocean is warming that the ice glaciers are melting that Global Warming exists or that the model estimates for temperature are not valid assuming that you agree with the future estimate for the solar input The conclusion is just that the SUN causes it and the CO2 concentration is basically irrelevant and along with water vapor self regulating Man can not control the sun 54 John Dodds says 19 May 2005 at 4 28 PM William Re 53 Response I think you are fairly well confused here You appear to think that there should be some relation between the solar radiation variation and the GHG radiative forcing There isn t Yes I agree I am VERY confused about what a forcing is I have read all of Ch 6 in IPCC It doesn t make sense It makes so little damn sense that I do not believe ANY conclusion that comes from a forcing chart AND that is the only place I have seen any evidence that CO2 as opposed to the sun is the cause of global warming Response When you read a large scientific document tht has undergone extensive peer review and survived very hostile scrutiny and you discover that you don t understand it then there are two possibilities a its wrong b you are wrong Naturally possibility b is not so pleasant to contemplate so you re inclined to go for a but an awful lot of other people have read it and do understand it and do agree with it So I think you need to brush up your understanding of the science William Re there being NO relationship between a solar radiation variation and a GHG forcing This may be true of a Forcing but it is NOT true of reality It is the solar radiation that causes the greenhouse effect If there were no change in the solar radiation then there would be no change in the temperature energy content of the air If you add CO2 under conditions of no change in solar then the CO2 with its higher heat capacity steals some of the energy from the other air molecules THERE IS NO change to the air temp YOU CANNOT CREATE ENERGY temperature OUT OF NOTHING Response Because the recent changes in solar output have been small and don t fit the temperature record at all well This observation is NOT relevant It happens EVERY DAY The solar increases from dawn to noon The air temp increases from dawn to mid afternoon due to earth response time lags even tho the solar has been reducing since noon Associated question Just what does the CO2 box in a forcing chart represent since apparently solar irradiance is different from a solar forcing per response 52 Is it the change in energy m2 for the CHANGE in CO2 eg from 1750 s 290ppm to 378ppm or is it the TOTAL CO2 all 378ppm or what Just where is the energy forcing part that comes from the natural change in solar irradiance acting on the natural 290ppm 75 of CO2 vs the part that comes from the change in irradiance acting on the change in CO2 ie the anthropogenic CO2 25 are they both in the CO2 box if so how can you conclude that anthropogenic CO2 is causing global warming or is this another item missing in a Forcing chart I am totally confused about what a forcing chart represents and can be used for AND especially confused about trying to draw ANY conclusions from it The IPCC Ch 6 is of no help Response Forcings are just a metric we use to be able to compare different changes to the climate It happens to be that the forcings which can be calculated very easily actually are able to tell how a model will eventually respond to different forcings without you having to do each individual experiment The forcings we are talking about in the IPCC graph or as shown in the Planetary Imbalance post are essentially the global annual mean energy flux difference at the tropopause when you instantly change the composition or the solar input and then recalculate the radiation All the forcings are defined as differences from say 1850 to the present Thus it is only the change from 280 to 380 ppm for CO2 that is counted and only the change in irradiance Because it is a global mean number you need to adjust the change in solar constant for the geometry and the albedo as I explained above No one is disputing that almost all the energy comes from the sun but we are looking at CHANGES in the energy fluxes not the absolute numbers gavin 55 Blair Dowden says 19 May 2005 at 8 50 PM Gavin thanks for your response to 51 Increasing aerosols is interesting and probably significant although I am sure there are large uncertainties in both the amount produced in that timeframe and what their effect is The recent global dimming issue illustrates that the effect of aerosols is still not well understood I thought volcanic effects lasted for only a few years and would not greatly affect a 30 year trend I am interested in what is meant by a plateau in both the greenhouse gas forcing and solar Greenhouse gases were increasing in that period are you saying there was a saturation effect The 1940 1970 cooling does not appear that significant on the graph on this page but does in other graphs I have seen particularly the one on page 4 Observed Arctic Temperature 1900 to present in the summary of the recent Arctic Climate Impact Assessment I notice that a similar dip around 1960 is present in both graphs presumably a short term volcanic effect 56 Heiner Grupe says 20 May 2005 at 6 15 AM Re 3 As figured out climate science has a communication problem But not only NGO s and enviro hysterics exaggerate Why is HAnsen himself talking about the proof and the smoking gun Such terms are not helpfull at the state of debate we achived 57 John Dodds says 21 May 2005 at 4 35 PM OK OK You all have convinced me A forcing is a man made device that is used for estimating responses in the GISSWorld computer model It has nothing to do with reality Forcings do NOT comply with conservation of Energy because the solar forcing the SOLE significant source of energy to the Earth ecosystem is smaller than most of the other forcings You can NOT draw conclusions from forcings because the forcings charts are NOT cause and effect charts and because they are incomplete eg no WV feedback no ocean energy content no longwave out numbers etc etc SO where does the conclusion that GHGs are causing global warming come from GHGs are totally incapable of generating energy They can only absorb the solar in energy If you put a container of CO2 in the sun it will come to the equilibrium temperature of the surroundings CO2 is not magical it cannot generate energy to get to a higher temperature than the surroundings The 50 high school physics concept that the SUN the sole source of energy is the cause of warming is STILL VALID The solar irradiance has increased since 1700 The earth model due to lags is not yet there it is warming The air adjusts daily to the new equilibrium The ocean with a bigger mass slower response time is still warming The land is VERY slow probably hasn t budged The solar irradiance energy in exceeds the energy out Hence the world is warming up to come to equilibrium Which according to the GISSWorld model is in a few hundred years and several degrees away but IF AND ONLY IF the solar irradiance stabilizes The fact that the recent changes in solar energy are small 50 response i is irrelevant Every day the changes in solar energy after noon are negative and yet due to earthly lags the air temp continues to get warmer for a few hours Maybe we are rolling over into cooling as the solar gets smaller For Response ii Yes the longwave is smaller that is because there is a net energy imbalance because the earth is heating up and absorbing energy to try to reach the equilibrium IMPOSED by the changes in solar irradiance in The energy balance is VERY SIMPLE Why are you complicating it with forcings and extraneous ecosystem model details to get the warming conclusion The GISSWorld model by itself is a real wonder seriously no sarcasm intended given all the things it models etc It is very useful to predict what the temerature increase will be and when it may occur IF none of the assumptions change AND the only one that matters is the solar insolation ie solar irradiance modified by orbital etc factors If it decreases or is flat like it was from 1300 to 1700 or 1999 to 2000 and 1940 70 or like it does from noon to dawn everyday at a specific location then the earth will cool WITH the appropriate lag time factors The amount of CO2 in spite of its greater heat capacity is irrelevant since it is small compared to the total earth mass The CO2 will absorb or release as much energy as is required to come into balance with the solar in energy and its immediate surroundings and probably within a few minutes if not hours WHY are you complicating this The sun causes the earth warming and cooling not man It is the ONLY significant energy source CO2 GHGs can NOT CAUSE temperature changes They can only react to solar imposed forcings to come to a new equilibrium Using Kyoto to change the level of CO2 will have absolutely ZERO effect on global temperatures It will however cost a fortune If there is less CO2 then there will be more water vapor feedback UNTIL we reach the equilibrium temperature imposed by the solar insolation If there is more CO2 then there will be less N2 O2 and water vapor at the SAME equilibrium temperature imposed by the sun The Hansen paper cited above with Gavin as a co author is JUST PLAIN WRONG is assigning a warming cause to GHGs Response Sigh Almost every line here contains an error I ve done my best to try and explain what the forcings charts show why we think greenhouse gases have an impact on surface temperatures why we think solar forcing is a smaller term but there are limits The situation is not very simple if it were we

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  • The Surface Temperature Record and the Urban Heat Island « RealClimate
    this postulation from meteorologists 3 Jim Dukelow says 15 Dec 2004 at 5 08 PM A couple of comments on UHI 1 The effect of urban heat islands on global and regional averages could be reduced if the compilers of the temperature datasets used area weighted averaging of the individual station temperatures This could be done fairly easily and rigorously using the Voronoi grid induced by the station locations The numerous stations in and around large cities would be down weighted and rural stations would tend to be more heavily weighted 2 Three years ago I tried to get a handle on whether UHI was responsible for the recent warming trend in most of the temperature datasets by comparing the trends for the UAH MSU 2LT channel and the Jones et al surface data for some of the world s empty places Location MSU deg C per decade Jones et al deg C per decade N Quebec W Labrador 0 317 0 327 N Ontario James Bay 0 413 0 533 N Alb Sask Man 0 424 0 470 E Yukon and Nunavut 0 101 0 666 N Alaska 0 191 0 008 SW Alaska 0 196 0 013 Arabian peninsula 0 021 0 328 Sahara 0 105 0 346 W China and W Mongolia 0 335 0 328 Outback 0 007 0 057 Amazon Basin 0 183 0 171 Patagonia 0 013 0 049 All trends from the Idso s web site world temperature calculator at http www co2science com The MSU and Jones et al trends for these empty places are weakly positively correlated with r 0 426 Notable in this data is how strong the warming in the North is and how different the Southern Hemisphere is Jim Dukelow 4 Ferdinand Engelbeen says 21 Dec 2004 at 4 10 PM I have no idea how good the urban stations are corrected for UHI by rural stations For another discussion where to find the effect of aerosols I was looking for more or less reliable rural station data for North West Russia for the period 1945 2004 In the whole Northern halve of Russia there are only two Vytegra and Reboly six others ceased operation between 1970 1990 Only 7 urban stations did span the 1945 2004 period with between 102 000 and 8 million inhabitants Surface data are more adequately corrected for urban island heat effect in the US and other OECD countries But the problems can be found in non OECD countries especially around the equator Look e g to the data for Salvador a town of 1 5 million inhabitants That should be compared with rural stations to correct for urban heat island effect But the nearest rural stations are 458 542 km away from Salvador Caetite Caravela Remanso And their data are so spurious that it is impossible to deduct any trend from them Quixeramobin is the nearest rural station with more or less reliable data over a longer time span and shows very different trends than Salvador Or look at Kinshasha what a mess 1 3 million inhabitants Brazzaville opposite the Congo stream and something rural in the neighborhood Mouyondzi 173 km M Pouya 215 km Djambala 219 km East Africa is not better compare the trends of Nairobi with these of Narok Makindu Kisumu Garissa Rural data trends with some reliability on a longer time span are very rare in the whole tropics Only expanding towns have sometimes longer data sets which are hardly correctable The unreliability of the data in the tropic range is thus obvious that one can wonder how a global surface temperature trend can be calculated to any accuracy Response You really need to read the Peterson paper more carefully His assertion and indeed Parkers is that the series don t need any correction But I guess if you really wanted a rural station near the coast you could just use the nearest ocean gridpoint William That one can make different surface trends depending on the method and corrections used can be seen in http www ncdc noaa gov oa vose panel ppt from the October 2003 Asheville NOAA workshop IPCC global surface temperature trends GHCN 0 31 ºC decade Jones 0 25 ºC decade and GISS 0 18 ºC decade For well maintained Australia GHCN 0 18 º decade Jones FDM 0 14 ºC decade Jones CAM 0 10 ºC decade Response I know you re aware of http www grida no climate ipcc tar wg1 053 htm so I m a bit puzzled by you posting that William 5 Kaleberg says 23 Dec 2004 at 11 13 PM Does the increasing area of urban heat islands increase global warming Are they in some kind of equilibrium or have they increased the overall surface warming 6 Pejk says 27 Dec 2004 at 5 10 AM Some considerations regarding the surface temperature record relate to the measurement techniques themselves The thermometer radiation screens affect the sensor readings A factory new Stevenson standard screen still allows solar radiation impact on the temperature measurement of more than one degree Accumulation of dirt growth of mnold even flaking of paint is naturally occurring over the life cycle of some 15 years that the product is used in the field The radiation error then multiplies Weather services try to control this by regular inspection maintenance and replacement programs which are more or less succesful in practice I assume these programs have changed for the better over time In the climate statistics such improvement should be present as a cooling trend although it would be difficult to identify Probably a larger impact is from changes of the ventilation techniques used In the older days and in many parts of the world still today thermometers were installed inside naturally ventilated screens The temperature measurement then depend on elevation angle of the sun on prevailing cloudiness and the wind speed at the time of measurement The forced ventilation technique using a blower can remove the

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  • Planetary energy imbalance? « RealClimate
    any particular flux which can be large and the second is the error in the overall balance which is very small To see why these things are different think of a lake which is fed by a number of streams of uncertain flow and drains into a river If the lake level is steady I know that the inputs are balancing the outputs even if I don t know their exact magnitude If I now observe the lake level change I can calculate very exactly the net imbalance regardless of the error in my estimate of the individual streamflows gavin 9 Robert Simmon says 3 May 2005 at 6 06 PM regarding comment 6 but measured by the same satellites They re not the same satellites Hansen et al used sea surface altimetry data TOPEX Poseidon and Jason Wielicki et al and Chen et al used flux measurements CERES Thus any imbalance no matter what the origin is which leads to higher SSTs is counteracted by more loss of energy to space Is inaccurate From A Delicate Balance a NASA article I illustrated â We are likely seeing a decadal fluctuation here Right now we are looking at what might lead to such a fluctuation â says Chen He believes that this is a natural climate anomaly much like El Nià o La Nià a or the North Atlantic Oscillation It is a natural part of the rhythms of the Earthâ s climate system But unlike these other anomalies the Hadley Walker cell fluctuates over the course of decades instead of years Chen feels that this phenomenon has no direct relation to global warming or any other hypothesis related to climate change including the Iris Hypothesis The Iris Hypothesis states that as sea surface temperature increases due to climate change the increase will alter the extent of certain types of overlying clouds so that the excess heat is allowed to vent through the top of the atmosphere Though the Iris Hypothesis may seem to jibe with what has occurred over the past 15 years in the tropics Chen says that the thermal radiation leaving the top of the atmosphere has increased much too rapidly Evidence has also shown that the clouds above the tropics are not changing in the ways predicted by the Iris Hypothesis 10 Doug says 3 May 2005 at 7 59 PM The report says Continuation of the ocean temperature and altimetry measurements is needed to confirm that the energy imbalance is not a fluctuation If it were a fluctuation could that mean the imbalance is just a short term thing that could reverse in a few years If so does that invalidate the following claim just posted Firstly as surface temperatures and the ocean heat content are rising together it almost certainly rules out intrinsic variability of the climate system as a major cause for the recent warming Response The longer the record the more sure we will be that what is seen is more than a fluctuation However given the match of the data and models using the most up to date forcings we are reasonably confident that it is not a fluctuation There is always a chance that nature is conspiring against us and so continued monitoring is essential to stregthen the conclusions gavin 11 Dave Dardinger says 3 May 2005 at 8 57 PM Just how accurate are the temperature measurements made in the ocean Working through the numbers we re only talking a few hundredths of a degree a year of temperature change It looks like your reference 19 J K Willis D Roemmich B Cornuelle J Geophys Res 109 C12036 doi 10 1029 2003JC002260 2004 would be the one with the data Is it available on line Response Try here In general ocean temperature measurements are very high quality and routinely reported to the third decimal place The bigger problem is spatial coverage but the addition of integrated constraints from the altimeter data goes some way to correcting for that gavin 12 Isaac Held says 3 May 2005 at 9 03 PM Gavin I agree completely with the standard picture that you describe but I don t agree with the claim that as surface temperatures and the ocean heat content are rising together it almost certainly rules out intrinsic variability of the climate system as a major cause for the recent warming Suppose that there has been a multi century increase in the poleward heat transport in the oceans due to internal variability which warms the poles reduces ice extent and albedos and thereby warms the planet The land surface and atmosphere go along for the ride having little heat capacity There is no evidence for anything of the sort but I don t see any logical inconsistency we need to be careful not to claim too much thereby creating an opportunity for a critique that is besides the point The consensus picture that you paint is convincing because the estimated forcings the models and the observations are all consistent not because of an argument that internal variability has to cool one part of the system in order to warm another Response Isaac I agree with your general point that a redistribution of heat in the system can alter feedbacks in a way that could affect the energy balance The obvious example is collapse in the North Atlantic MOC which leads to more sea ice etc However the impact on global as opposed to local temperatures of even large variations in the overturning is very small Thus it doesn t appear to be much of a practical effect For the case at hand though the distribution of heat anomalies in the ocean makes a redistribution feedback effect very unlikely gavin 13 dave says 3 May 2005 at 10 42 PM Good post What are the model assumptions about radiative forcing from clouds Is Earth s cloud cover increasing decreasing Are there any new observations about this and the types of clouds involved Response The models cloud radiative forcing is a diagnostic of the model rather than an assumption that is built in Clouds are however very important and we and other groups are trying hard to analyse what they are doing Comparison with data such as ISCCP is problematic because they records are noisy short and may still have systematic problems that affect the trends As and when those analyses are done we will report on them here gavin 14 g says 4 May 2005 at 2 25 AM I ll have to go to the primary references but this raises a few questions for me Is the record detailed enough to understand 3 dimensional changes in sea temperature or is it mostly based on sea surface altimetry In particular is there an observed or predicted change in the temperature or volume of mode waters or rates of deep water formation Can you use whole planet radiation budgets to calculate the planet s net entropy gain Is there a way to budget how much of that entropy gain is due to life 15 John Finn says 4 May 2005 at 4 59 AM Gavin You say since the current unrealised warming in the pipeline is related to the net imbalance 0 85 0 15 W m2 implies an further warming of around 0 5 0 7 C I am interested as to when this 0 6 C increase will become evident I have had a quick look at the Hansen paper and in it he says something to the effect that the time lag is roughly proportional to the square of the sensitivity So does this mean that if t is the time delay in years and s is the sensitivity t can be expressed as t k s 2 Dr Hansen also states that time delay could be as short as a decade if climate sensitivity is as small as 1 4 deg C per W m2 Substituting this i e t 10 s 0 25 into the above equation yields k 160 very rough I know Also in the paper the sensitivity resulting from the models appears to be about 2 3 deg C per W m2 so if we maintain the current level of forcing indefinitely this suggests the time delay before equilibrium is established is as follows t 160 x 4 9 which is over 70 years or have I got something wrong Also could you tell me if the increase in temperature towards equilibrium is expected to be linear This would mean a steady increase of 0 1 deg decade 0 6 in 70 years if my interpretation is correct Response This is all discussed more thoroughly in Hansen et al 1985 no online version unfortunately The basic idea is that since feedbacks are a large part of the response lags due to ocean thermal inertia slow down the full feedback response For the current imbalance and idea of how long it will take for the warming to come down the pipe can be seen in the figures in the Wigley and Meehl et al paper referenced above In the GISS committed climate change simulations most of the additional warming has occured by 2050 but there remains a slow increase for decades afterwards gavin 16 Isaac Held says 4 May 2005 at 9 00 AM Gavin Following up on my comment above my concern is with the smoking gun language and whether it might be counterproductive The idea is that there is a small set of observations and a theoretical argument that goes along with it that is essentially irrefutable even if one is unfamiliar with or rejects the rest of the edifice of global warming science I am not sure that this is a good tack to take since the argument in fact is not irrefutable and probably is not very convincing to someone who has no intuition for internal climate variability and how it manifests itself I wasn t supporting the idea of the dominance of internal variability but just addressing the logical consistency of the argument I think we need to emphasize the consistency of the whole picture and not place too much emphasis on one line of argument which is what the smoking gun language tends to encourage 17 Henry Molvar says 4 May 2005 at 11 37 AM Time 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 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 now 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 prescient short story Disney the Fall of an Empire by John M Crichton III written in 2035 by the young great nephew of the famous 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 of Crichton IIIâ s 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 health education housing etc have been eliminated or 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 1990â s and early 2000â s due to the unforeseen effects ofâ 18 Ferdinand Engelbeen says 4 May 2005 at 12 50 PM Re comment 9 of Robert Simon Thanks for the correction It seems to me that deducing heat content from altimetry is less accurate than from direct measurements as altimetry is influenced by wind speed and barometric pressure too The comment from NASA about the Wielicki findings and what models predict is very interesting especially at http earthobservatory nasa gov Study DelicateBalance balance4 html IMHO the increase in speed of the Hadley Walker cells may be the result of higher ocean temperatures or temperature differences over long distances not the origin or to a lesser extent as less clouds lead to some extra insolation thus warming Some indication for that can be found in several studies one of them at http hydro jpl nasa gov sst sst html This is not the same as the Iris hypotheses as that is on a much smaller scale but over the whole tropics subtropics The loss of energy to space measured by Wielicki e a in the past 15 years is of near the same magnitude as what the theoretical increase in greenhouse effect is from the extra greenhouse gases since the beginning of the industrial revolution That is a large impact Remains to be seen if the current 0 85 0 15 W m2 imbalance found by Hansen e a is not simply a part of the natural variability found by Wielicki if it is natural at all 19 Dave Dardinger says 4 May 2005 at 11 02 PM Re response to 11 Thank you Gavin for the link I ve sort of skimmed it so far There s a lot more to be looked at But I m afraid I m unconvinced that the 85 15 w m2 figure is very believable The problem is figure 6 which shows the spatial extent of the various storage values for each year They show both high resolution and high variability over short distances This wouldn t seem to me to be a sign of a highly accurate system Further compare say 1997 and 1998 where we switched to the super El Nino situation Very striking but also quite a problem The same areas of the ocean went from something like 80 w m2 to 80 w m2 or vice versa in less than a year And we re not talking single pixels but large sections of the ocean With such gigantic variability common expecting a decadal global average to be accurate within about 1 of the annual variability is asking a lot Response Well the 0 85 number is the mean from the models and so is not directly related to the uncertainty in the data However it s easy to assess the error in the global mean ocean heat content based on the measurement error and spatial variability and that is done in the Willis et al paper Despite the variability the global means are relatively well defined The key is that the tropical Pacific is actually very well sampled through the TOGA COARE array and the patterns you see in the annual means change slowly enough for the heat content anomalies to be well characterised As Willis et al states the errors due to spatial coverage rather than variability are more important Given that it s clear that the longer the record the more confident we will be gavin 20 Alain Henry says 5 May 2005 at 4 37 AM Thanks for another enlightening article When looking at the total forcing in the second part of the first graph whoch summarises forcings over the 1850 2000 period there is at first sight a long term rising trend including in the 1940 70 period well there is a significant fall in the sixties though due to solar irradiance I am thus looking for an explanation of the 1940 1970 cooling strong quotes The global temperature fall in the sixties can be linked to solar irradiance I assume But is there a good and intuitive explanation for the 1940 1960 period where it looks more like a global temperature stabilisation than a cooling or is it just the result of the complex interaction of the climate system Thanks Alain 21 Alain Henry says 5 May 2005 at 1 56 PM In comment 20 I mentionned solar irradiance as falling in the sixties and possibly explaining the low global temperature in the sixties I actually meant stratospheric aerosols I got confused by looking at a black and white printout of the figure Apologies for the confusion Alain 22 Dave Dardinger says 5 May 2005 at 2 07 PM re response to 19 OK I see what the 85 is then though I m not sure it s meaningful in that case It s very close to what the article you linked me to has 85 12 BTW Looking further at that article I examined figure 6 It shows a graph of the global heat storage over time I did a quick analysis of that estimating the value by eyeball for each year I ended up with 7 0 rather than 8 5 as I suppose it should be giving you an idea of how my aging eyes are doing I then put those figures in a spreadsheet calculated the trend y 1213x subtracted again by eye to get the difference total off by 3 and then calculate the RMS of the differences which amounts to ironically 85 Again it doesn t look real robust in terms of the trend being real as opposed to a fluxuation I d have been real careful about letting words like Smoking Gun be associated with your findings BTW since the data ends in 2002 have you gotten any preliminary data for 2003 and 2004 This would certainly help since the ending trend seemed to be down 23 Ferdinand Engelbeen says 5 May 2005 at 2 30 PM While rereading the ocean heat content changes by Levitus 2005 at http www nodc noaa gov OC5 PDF PAPERS grlheat05 pdf a remarkable sentence was noticed However the large decrease in ocean heat content starting around 1980 suggests that internal variability of the Earth system significantly affects Earth s heat balance on decadal time scales Thus it may be that the 1993 2003 period of ocean warming used by Hansen e a is an entirely natural warming My question The GISS climate model follows the 1993 2003 trend quite good But does it follow the 1980 1990 cooling trend as good 24 Stephen Berg says 6 May 2005 at 11 47 PM I thought you would be interested in this story http www cbc ca story science national 2005 05 06 global dimming050506 html Response Indeed This relates to a trio of papers in Science this week A commentary will be forthcoming gavin 25 Rick Watkins says 8 May 2005 at 3 33 AM I read in a school textbook that it takes as much energy to convert 1gm of ice at 0oC to 1gm of water at 0oC as it does to heat said gram of water from 0oC to 80oC With recent talk of the extra heat the earths system is absorbing hiding here and there is there a connection The energy taken from the system to cause the observed glacial melting worldwide thinning and shrinkage of Arctic sea ice melting collapsed Antarctic iceshelves etc must be hidden in the meltwater unrecordable by themometer Does this amount of energy rate a mention in the earths energy equation or is it too insignificant to bother with Response The latent heat of melting for ice is indeed large but given the amount of heat we are talking about and the relatively small amount of ice melt seen so far it is negligible Levitus et al 2001 did the calculation and the ocean heat content is by far the biggest term gavin 26 dave says 8 May 2005 at 6 50 PM Re Response Times It seems to me that Earth s Energy Imbalance paper is not strictly a science paper there are also policy warnings e g this example 0 6 C warming in the pipeline implies the need for near term anticipatory actions This deserves some more comment since the situation could be even worse than the paper states and this comment is not peer reviewed It is my understanding of the paleoclimate that only about half of the rise during interglacials to 280ppmv and fall during glacial maximums to 190ppmv of CO2 levels can be accounted for by climate models The rest presumably comes from unknown feedbacks in the biosphere The paper and presumably the climate model used does not deal with this issue but notes the sawtooth pattern Also it could be argued that the initial stages of ice sheet disintegration have already been detected WAIS Greenland but admittedly no one knows what this looks like Recent accelerated rates of ice sheet melting and our current ignorance is cause for alarm given that the destabilizing issue of comparable ocean and ice sheet response times is apparent The inferred positive eustatic GLSR from the ice sheets is a recent result But the real problem as I see it is that the slow response times of the oceans and ice sheets creates slow human response times with respect to policy to stabilize GHG levels So an equilibrium response is a convenient fiction which enables the science but is not a goal of policy makers and so can not exist in the real world Also the GISS model with it s 2 7c sensitivity is on the low end The Kerr 2004 Science Three Degrees of Consensus summary cited in the paper but not online gives the current range across models for climate sensitivity as 2 5c to 4 0c So there is ample reason to worry This paper dovestails nicely with Elizabeth Kolbert s 3 part series in the New Yorker on climate change Try here I ll let you know how it ends This is the last sentence of part 3 It may seem impossible to imagine that a technologically advanced society could choose in essense to destroy itself but that is what we are now in the process of doing Apocalypse Later 27 Stuart Hobbs says 8 May 2005 at 9 14 PM As a lay person to the climate sciences the debate over anthropogenic global warming is very confusing since there appears to be so many contradicting opinions For instance a candian television program about anthropogenic global warming seems to say almost the exact opposite of what is being stated here and in some of the recently published articles in Science Any opinion on this particular program and the bona fides of its experts 28 dave says 9 May 2005 at 10 40 AM Re 27 Confusing The friends of science website you reference is a propoganda site designed to sow the kind of confusion you feel Most such sites are sponsered by fossil fuels industry Here s an introduction to such sites at Mother Jones called As The World Burns Welcome to RC 29 Dave Dardinger says 9 May 2005 at 11 08 AM Re 28 Errr Mother Jones is not a propaganda site It s certainly far left 30 Stephen Berg says 9 May 2005 at 11 55 AM Friends of Science are an industry funded group affiliated with the Fraser Institute in Canada which receives funding from ExxonMobil to disinform and confuse to obfuscate the public They are certainly not what their name says Because of this I like to call Foes of Science As for the Errr Mother Jones is not a propaganda site It s certainly far left Mother Jones is a centre left newsmagazine which features excellent journalism and analysis Two of the three I don t know who Chris Mooney is who wrote in the As The World Burns issue are very good I have met Ross Gelbspan and he is a brilliant journalist hence his Pulitzer award Bill McKibben is also brilliant I would definitely recommend anyone read their work 31 dave says 9 May 2005 at 5 39 PM Re 24 Dimming I could have added in my remarks in 26 that these new global dimming results point to the conclusion that negative forcing from sulfate aerosols masked the actual ongoing warming up to about 1990 I look forward to your post on this subject Re 29 Yes sorry I couldn t find anything pertaining to climate skeptics in the Wall Street Journal 1 in Google for the query climate science skeptics Try Ross Gelbspan s Disinformtion page His site is The Heat Is Online linked in here at Real Climate 32 Manny says 9 May 2005 at 7 07 PM Re 28 I find it interesting that a particular organization might be indicted for supposedly being funded by the fossil fuel industry when so many organizations and studies fueling the global warming alarmism are funded by governments and not suprisingly endorse MORE government in the form of regulations regulatory agencies taxes fees etc as a supposed solution to the problem Talk about conflict of interest 33 Joseph O Sullivan says 9 May 2005 at 8 17 PM For Stuart Hobbs much of the information disputing climate change science is politically driven There is scientific consensus about climate change the earth is warming this warming is mostly caused by humanities release of greenhouse gases and this could be harmful There is scientific consensus because the evidence is overwhelming Look at the just what is this consensus Dec 22 post here on realclimate If the consensus is accepted the next step is to take action Action would mean enacting laws and regulations limiting the emissions of greenhouse gases These regulations would probably be extensive and be expensive A group of conservatives who favor small government and industries who could lose financially are adamantly opposed to these regulations and are the most vocal opponents They are hostile to environmental regulation generally and climate change regulation especially Current environmental regulations were passed after environmental groups ran political campaigns that reflected the public s call for action addressing environmental problems Conservatives and industry were stung by these political defeats Noting the success of environmentalists conservatives and industry founded their own political advocacy groups to oppose environmental regulation The groups spearheading this opposition are not independent academic institutions They are political advocacy groups as are many of these think tanks They advance conservative and corporate political agendas That is why conservative foundations and industry fund them For examples see http www environmentaldefense org article cfm contentid 3804 CFID 21084385 CFTOKEN 29888831 Being politically active for industry environmentalists or any other group is not a bad thing Any political advocacy group has an agenda and when evaluating their messages about climate change science it is important to examine how they advance this agenda Every political group uses spin to try to persuade the public but some of the groups that represent conservatives and industry use what can be called extreme tactics in the climate change science debate These groups including Fraser Institute and Friends of Science are waging a public relations campaign against environmental regulation Because climate change science when objectively examined supports environmental regulation science scientific institutions and scientists have also been subject to criticism The goal is to publicly cast doubt on the science so the public will not support climate change legislation See http www luntzspeak com graphics NewYorkTimes NewsStory pdf Without public support it is unlikely any climate change regulation will be enacted Even conservative politicians who support climate change legislation have been targeted The claims about climate change science made by these conservative industry groups have questionable scientific value Most of these claims are political attacks that promote a partisan agenda and are not objective information about climate change science Concern about policies based on science is understandable and can be used to create better policies but in many cases the concern about policies is prompting some to misrepresent the facts about climate change science 34 Manny says 9 May 2005 at 9 31 PM There is scientific consensus about climate change Perhaps you have not seen the video at the link Stuart provided Regardless of what you think of how they are funded the video clearly shows climatologists disputing the consensus viewpoint 35 Joel Shore says 10 May 2005 at 9 24 AM Re comment 34 Consensus does not mean unanimity You can find a few PhD biologists who dispute the theory of evolution too but that doesn t mean there is a lack of consensus on the issue in the peer reviewed scientific literature If you look around the Friends of Science site you will see just how pathetic it is Their motto probably should be No argument is too ridiculous for us They even try to sow doubt over whether the current rise in CO2 levels is primarily the result of humans 36 Thomas Nephew says 10 May 2005 at 3 12 PM I can t tell from Table 1 what share of GHGs are contributed by volcanic greenhouse gases is this an unknown part of the 2 75W m2 figure Or are volcanic GHGs known to be negligible I m obviously a newcomer to these questions Also are undersea eruptions likely to contribute significant heat to ocean temperatures If so perhaps the argument is still that your model matches observed temperatures well enough so adding this input is unnecessary But assuming a number could be put to this heat source would it draw down the other forcings proportionately or would it all come out of GHGs 37 Stephen Berg says 10 May 2005 at 3 55 PM Re 36 Read my comment 20 on the thread for my answer to Also are undersea eruptions likely to contribute significant heat to ocean temperatures http www realclimate org index php p 124 38 Thomas Nephew says 10 May 2005 at 5 22 PM I have no idea how frequent undersea eruptions are or how constant their rate is from one century to the next I m guessing you probably don t either But you raise a good point that if the heat release per century is constant that can t account for rising temperatures Maybe one can reasonably infer fairly constant undersea vulcanism from on land vulcanism I m hoping I ll find out here But the thing is even if it s constant if there s a lot of it I would think that might affect the man made GHG argument It seems like it would have to come at the expense of some other heat source for the model to work as well as it does On the other hand then it might take less GHG to cause the observed temperature increase That might actually be good news in that reducing GHG would have a correspondingly big effect too 39 Dano says 11 May 2005 at 11 50 AM Re 34 there is only one climatologist in the video and that person didn t bother to correct the copy that allowed the non climatologist to state the UHI is contributing to the surface temperature rise That very simple fact should raise alarm bells and cause one to scrutinize other statements in the video D 40 John Dodds says 11 May 2005 at 4 21 PM Do I understand this Ocean data correctly It was said above that the ocean is warming just like the land air and ice sheets glaciers that the heat in the ocean dwarfs that in the land and air that the warming is due to the net solar imbalance solar in less LW out no mention of CO2 Response The NYT quote from Wielicki is incomplete he meant that the net imbalance measured by CERES SW and LW is consistent with the ocean heat storage data I quote from an email posted on the climatesceptics group From Bruce A Wielicki To Willis Eschenbach Subject Re The Studies of Drs Wielicki and Hansen Willis The times reporter got the sense of it but not all the specifics your confusion is about longwave flux forcing of CO2 vs shortwave solar albedo changes my comment to the times was that if you put the shortwave reflected and thermal infrared emitted energy terms together and look at them over the last decade for 1992 to 2004 you get variations in net radiation into the Earth that vary up and down with peak variations of about 1 W m 2 but that have fluctuations very consistent with total ocean heat storage as they should The net planaetary imbalance has very little to do with the sun gavin THE SUN IS CAUSING THE GLOBAL WARMING and we can t do a damn thing about it makes sense to me since it is also the sun that supplies the heat to drive the greenhouse effect SO no matter what we do to CO2 by Kyoto we are at the mercy of the sun and the imaginary Pipeline and when the sun decides to cool off and reverse its 300 year warming trend see IPCC solar irradiance history http www grida no climate ipcc tar wg1 245 htm we will go into global cooling like we did from 1300 to 1700 and 1940 1970 It will cool off someday it always has in the past just look at the sawtooth ice core temperature data Which by the way will immediately eliminate the energy in the imaginary Pipeline seems as if this happens just after noon every single day The next conclusion is that any prediction of air temperatures for the next 50 years is totally dependant on the assumption made for what the solar irradiance levels are Which according to this study is a factor of TWO total incredulity Excuse the dumb question but why are we wasting our research time on CO2 emissions rather than the cause of changes in solar irradiance BUT that if we continue to add CO2 to the air the air has the added heat capacity to get warmer IF and ONLY IF driven by the sun but rapidly come to equilibrium with the ocean by means of rain and the daily heating condensation of the water vapor feedback mechanism BUT already the air never gets to maximum heat capacity anyway Other than the fact that CO2 is necessary to human survival we breathe it out after processing hydrocarbon food and for 98 of the energy that has allowed us to live longer and improve the standard of living over the last 300 years just why exactly do we even care how much CO2 is in the air especially if the temp of the ocean which is dictated by the sun will dictate the air temp I observe this daily in chilly San Francisco 41 Dave Dardinger says 11 May 2005 at 5 05 PM re 39 The question isn t whether UHI contributes to surface temperature rise but whether it affect temperature measurements sufficiently to bias the measured averages All I can say is that in the northern US at least the temperatures in the outlying suburbs were always lower than those at the airport and higher than those in the countryside And Columbus OH was not that large a city in the 50s and 60s that it probably has had much of an adjustment made to its temperatures 42 Dano

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  • Climate sensitivity « RealClimate
    forcing mainly because there is a more important ice albedo feedback in the soot case The ideal metric of course would be a forcing that can be calculated easily and where every perturbation to the radiative balance had an relative efficacy of 1 Unfortunately that metric has not yet been found Comments Off on Climate sensitivity Comments are closed Site Google Custom Search Recent Comments Unforced Variations Feb 2016 Digby Scorgie Unforced Variations Feb 2016 T What is the best description of the greenhouse effect Jim Eager What is the best description of the greenhouse effect Patrick Eriksson What is the best description of the greenhouse effect Kevin McKinney Anti scientists Carbomontanus What is the best description of the greenhouse effect Spencer Marvel et al 2015 Part III Response to Nic Lewis SteveS What is the best description of the greenhouse effect Chris Colose Blizzard Jonas and the slowdown of the Gulf Stream System doiknow 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

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    they are decreasing Have you queried the model as to what the dominant mechanism s is are that caused the cooling If so is are the mechanism s plausible Can the be verified independently A This isn t much of a test The models are pretty stable in the absence of forcing changes although there is some centennial variability as noted above related mostly to ocean circulation sea ice interactions Of the forcings factors that cause cooling they involve increasing amounts of reflective aerosols deforestation reducing greenhouse gases having more volcanoes etc For periods such as the last ice age increases in ice sheets are a big cooling factor and more recently the 1940s 1970s cooling is a combination of increasing aerosols increasing volcanoes particularly Mt Agung in 1963 and a slight decline in solar forcing overcoming a relatively slow growth in greenhouse gases All of these things are physically plausible and the verification lies in the prediction of ancillary changes water vapour changes circulation etc that were observed but that aren t specifically related to the global mean temperature Have you tested the model against simplified analytical solutions Are you able to accurately reproduce analytical results A Unfortunately analytical results are in very short supply in climate science If there was an analytical solution for climate we wouldn t need numerical models at all Some individual components can be tested against standard solutions i e idealised tracer distributions for the atmospheric dynamics the radiation scheme against first principle line by line solutions etc but for the climate system as a whole only numerical results exist For the evaluation of that you need to compare to real but imperfect observational data How do you address the issue that models cannot be used to predict the future In other words models can only predict what might happen under a given set of conditions not what will happen in the future A Exactly This is what the IPCC scenario excercise is all about and why the model simulations for the future are called projections not predictions No one in this game ever thinks they are predicting the future although it often gets translated that way in the popular press We take assumptions that people have made for the future and this is not restricted to IPCC and see what consequences that would have for the climate Sometimes though those assumed conditions eventually turn out to be quite close to reality and so it is worth revisiting the old projections and evaluating the results The simulation used by Hansen in his Senate testimony in 1988 is a good example as are projections of the impact of Mt Pinatubo made in 1991 In my opinion Crichton s most valid criticism of modeling work is that there is no independent study of model results by other investigators How do you address this A It might be valid if it were true but it isn t For instance for the next IPCC report over 300 independent

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    take functions from theorectical physics and historical data to support the projections of the models I would have thought that theoretical physics and historical data would have been used in part to construct the models Am I missing something Response I think you ve missed the point which is that many people seem to think that concern is entirely generated because of model output This is wrong The models are merely trying to quantify the warming that theory and observation tell you to expect anyway William 14 Tom Rees says 24 Oct 2005 at 5 21 AM Re 8 about the maximum warmth possible in the GISS model You might like to know that an older version of the GISS model has been put in a nice graphic wrapper to make it easy to run on PCs It s lower resolution than the modern models but otherwise fully functional in fact it s the same model that Hansen used in 1988 to make his famous prediction You can plug in new values of CO2 and solar methane CFCs and see what happens for yourself The website is http www edgcm org 15 Mark A York says 27 Oct 2005 at 12 00 PM Here s what your average naysayer is using as proof this whole thing isn t real Dr Gray What would you say to him personally about his views Response Dear Mark thanks for pointing out this article Dr Gray there says I m not disputing that there has been global warming There was a lot of global warming in the 1930s and 40s and then there was a slight global cooling from the middle 40s to the early 70s And there has been warming since the middle 70s especially in the last 10 years But this is natural due to ocean circulation changes and other factors It is not human induced I ve spent the past 15 years studying the effect of ocean circulation on climate in past future and present and I have many publications on this see my website A change in ocean circulation redistributes heat in the climate system but has only a small effect on the global mean temperature E g an increase in Atlantic thermohaline circulation would have warmed the North Atlantic region but cooled the Southern Hemisphere because there is simply more heat transported from the Southern Hemisphere into the North Atlantic then I would ask Dr Gray to point me to a single scientific paper which shows how 20th Century global warming could be explained by ocean circulation changes If there is no such peer reviewed paper and I certainly do not know any then I would ask him to refrain from making such public claims about it I would ask Dr Gray how the ocean circulation has changed and what the evidence for this is I would also ask him to specify what the other factors are that explain the recent global warming and point me to peer reviewed papers demonstrating this And finally I d ask him how he knows that it is not human induced this sounds like a very definite statement so I would like to know what the supporting scientific evidence is given that it is well established physics that the amount of greenhouse gases which we released to the atmosphere has a radiative effect that can easily explain all the observed global warming Would not any sober and unbiased analyst of the scientific evidence conclude that at least it is quite possible that the warming is human induced It makes me highly suspicious if someone claims absolute certainty that it s not without giving any rational argument as to why he believes this And strange the interviewer let him get away with such a claim without asking what makes you conclude that Dr Gray further states So many people have a vested interest in this global warming thing all these big labs and research and stuff The idea is to frighten the public to get money to study it more This simply insinuates hidden and egotistical motives in a lot of scientists including myself I have little respect for people who resort to such ad hominem attacks rather than using factual arguments Besides what most climatologists including myself are saying actually is we know enough to act or as California governor Schwarzenegger put it the science is settled the time for action is now We are not saying we are still uncertain about the greenhouse effect please give us more money to study it I come from a country where the government listens to what science has to say I am a member of the Advisory Council on Global Change of the German government and the result is that funding for basic climate research like my own work is being reduced and money is invested to work on solving the problem e g renewable energy research Hence the advice that scientists like myself are giving is actually against our own funding interests but in contrast to what Dr Gray seems to believe there are actually many people in this world including scientists who are not corrupt and who put the public good above their own vested interests Stefan 16 John Dodds says 27 Oct 2005 at 12 22 PM Re 6 Response by Stefan http www realclimate org index php p 193 comments 1 is undeniable Man is increasing the CO2 in the air 2 CO2 is a greenhouse gas that will warm the climate The fact that CO2 is a greenhouse gas absorbing long wave radiation is based on lab measurements and was recognized in the 19th Century But remember that Arrhenius first did it in 1896 without computer arriving at 4 6 ºC warming for CO2 doubling So if we had no computers we would still have arrived at a very similar estimate of climate sensitivity albeit less certain OK yes CO2 absorbs some of the IR energy that is generated by the air 288K Now what happens to that CO2 molecule Try this after absorbing the photon or energy the CO2 is 900K It is so hot that it bumps into a whole passel of air molecule neighbors who are at 288K or less In fact at ground level it hits the first one in about 8 millionths of a centimeter apparently The absorbed energy is so rapidly returned to the air molecules that the air and the CO2 returns to its original 288K in microseconds Any CO2 molecule that is warmer than its surroundings will ALWAYS bump into a cooler neighbor they will all adopt the same equilibrium temperature unless it reemits the photon to the air or space and returns the CO2 to its original temperature Because there are more air molecules than CO2 the energy return by collision is the faster more dominant process Conservation of energy requires that the air 288K first give up energy to radiate it the energy is absorbed by the CO2 the energy is returned to the air by collisions Net result NO CHANGE IN THE SYSTEM due to the CO2 absorption Sorry to say but Arrhenius was wrong can I have a Noble Prize for daring to say this Response Try publishing your theory in the scientific literature first will be hard to get a Nobel prize without that or is denouncing a Swede automatic denial for the Swedish Nobel Prize His analysis did not go far enough He only considered CO2 absorption as do the current computer models and ignored the return of the same amount of energy by molecular collisions The actual net result by high school physics of adding energy to GHGs is NOTHING The energy is always returned to the air from which it came because the air is the source of the Stefan Boltzman radiated energy simple pure conservation of energy GHGs do NOT trap and retain energy they use the environmentally sound trap and release philosophy they pass the energy through from ground level eventually to space and they do a much better job of it than convection or conduction OK Gavin Stefan where is this wrong it is so extremely obviously simple when you think it through rather than accepting the 100 year old idea that a greenhouse gas traps energy Response It is amazing how often lay people write letters claiming that the experts have overlooked the extremely obviously simple for over a hundred years Not so likely right Every scientist coming fresh into this field has looked at and understood this again rather than sheepishly accepting what Arrhenius said and remember many of us teach this to university students every year they do ask the critical questions until they have understood the energy balance I m afraid you simpy have not understood the basics of how the greenhouse effect works You re wrong in two points First only some of the energy is absorbed i e goes into molecular collisions while some is re radiated in all directions Some of that is re radiated back towards the ground where it increases the incoming radiation you can look up the exact numbers in any textbook or the radiation budget graph in the IPCC report That extra radiation coming from the CO2 molecules aloft warms the surface Second the energy absorbed by the CO2 leads to warming of the surrounding air molecular motion heat Arrhenius knew this and all models take this into account of course Stefan This is also the same mechanism used in a glass greenhouse The longwave energy emitted from the solar radiation absorbed by the ground is absorbed by the CO2 and water vapor the GHGs and then transferred to the air inside the greenhouse by collisions However the GLASS of the greenhouse confines the air and heat to the inside glass being non transparent to longwave or IR energy and air molecules thus allowing it to get hotter than the outside air ie the true greenhouse effect Opening a window will allow the heat to escape by convection or movement of the air The amount of GHGs CO2 or water vapor is irrelevant since it acts only as a transfer mechanism heating up all the air which includes the GHGs If the GHGs were not in the greenhouse air then normal convection and conduction would STILL transfer the sun s heat energy from the ground to the air but not as efficiently in the same or reverse way that conduction of heat through the ground or glass will cool a greenhouse down overnight when there is no continuing solar radiation heat source and regardless of the GHG concentration For the IPCC enhanced greenhouse effect in the current atmosphere where mankind IS increasing the amount of GHGs CO2 there is no glass to confine the heated air so the heat energy is distributed globally The GHGs still act as a transfer agent absorbing the ground radiated longwave or IR energy and then transferring it to the air until the energy reaches the upper atmosphere where it is radiated to space Both convection hot air rising and conduction hot air heats up cool air by collisions contribute to the transfer of the ground heat energy to the air and WOULD DO SO even more if the GHGs did not exist see the IPCC figure http www grida no climate ipcc tar wg1 fig1 2 htm The greenhouse effect ie ground level temperature is warmer than the 255K equilibrium temperature would still be there even without the GHGs another argument for why the quantity of GHGs is irrelevant The decreasing air temperature gradient from the ground 288K 15C to the effective mean radiative equilibrium level 10KM and 255K where the incoming solar energy balances the outgoing earth radiated energy is basically dictated by the decreasing energy flux and the corresponding decrease in air density both of which are dictated by the inverse square law ie bigger volumes at larger heights means less energy per square or cubic meter flux or less matter per cubic meter density The amount of GHG transfer agents does not significantly influence the temperature because the GHGs instantly lose any absorbed energy by colliding with the other air molecules The GHGs do not retain any more energy than the overall air because if they were hotter then collisions would soon within microseconds cool them down to the air temperature Also since the source of the radiated energy that is resulting in the increased flux and absorption is actually the air and GHGs itself then just how can the air heat itself up to a temperature than what it started at Sorry people I am not an activist trying to disrupt the world or a paid consultant to the oil companies I simply do NOT understand the high school physics basis for the greenhouse effect where a GHG is supposed to absorb and retain energy My understanding says it doesn t exist if it doesn t exist then there is no basis for GHGs causing global warming If someone can explain it please do but do it in simple single molecule and energy terms In my global warming education I have at least accepted that the hockey stick exists and the world IS warming and that when you emit CO2 you remove twice as much O2 for a net loss of air density so I can accept sound logic BUT the Arrhenius CO2 warming the world concept doesn t meet the common sense or basic physics test 17 Dan Allan says 27 Oct 2005 at 4 39 PM John The greenhouse effect does not depend on the heat staying permanently trapped in the atmosphere It just depends on the average photon s heat staying in the atmosphere a little longer than it would have without the co2 What if there were just one co2 particle in the atmosphere that continuously absorbed and then transferred heat Wouldn t the atmosphere be miscroscopically warmer for this than if there was no co2 Don t forget that as soon as it transfers it s heat it s ready for the next photon so at any point in time there is more absorbed heat in the atmosphere than without it 18 John Dodds says 27 Oct 2005 at 6 11 PM Re 17 You are missing the point The photon comes from the AIR is absorbed by the CO2 IN THE AIR is returned TO THE AIR by molecular collision The energy NEVER leaves the air There is NO energy added to the system by the CO2 if no energy is added then it can t warm up Arrhenius ignored the return of the energy to the air He was wrong Even if you add CO2 since the energy from the solar in sunlight is fixed and is continuously being radiated from the earth so that at equilibrium energy in equals energy out then ADDING CO2 can NOT absorb more of the energy in because there is NO MORE energy in to absorb It was ALL already being radiated out by the preexisting CO2 before the extra CO2 was added The CO2 can NOT absorb extra energy if there is none to absorb Hence NO WARMING unless the sun does it Where does the warming energy come from I think it was created out of nothing in the computer or on Arrhenius paper 19 John Dodds says 27 Oct 2005 at 8 34 PM Add another question to 16 18 If you accept that the GHG Forcing is created by the energy that is added by the absorbtion by the added CO2 sounds fine to me AND you accept that the absorbed energy is returned to the air by molecular collisions I do not see much CO2 at 900K from the absorbed photon out there then WHERE is the Forcing that accounts for the energy that was returned to the air It will be equal and opposite of the GHG forcing that supposedly accounts for the global warming If it is ignored then Arrhenius and the Computer Models are WRONG 20 wayne davidson says 27 Oct 2005 at 11 53 PM Did I hear right NOAA s and other models are predicting a very cold 2005 06 winter Can anyone explain how this happened What kind of model projects a very cold winter following a world wide very warm fall 21 Theo Kurten says 28 Oct 2005 at 4 41 AM Re 16 18 John I think you are missing a central point The IR photons in the lowest part of the atmosphere are not generated by the air 288K but by the Earth s surface Without GHGs these photons would pass straight through the atmosphere Due to GHGs they are absorbed and as you quite rightly point out quickly re emitted multiple times As a result the lower part of the atmosphere is warmed Indeed without the collisional energy transfer the greenhouse effect wouldn t even work or at least not so effectively This is analogous to passing a beam of EM radiation of some suitable wavelength through a container with some gas inside If the gas mixture contains molecules that are able to absorb at that wavelength then the gas warms up If not it doesn t Another analogue would be a microwave oven According to your reasoning a microwave oven should not be able to heat up anything since the molecules that absorb MW photons ALWAYS bump into a cooler neighbor they will all adopt the same equilibrium temperature 22 Timothy says 28 Oct 2005 at 4 48 AM Re 16 John The energy is in your photon The photon travelling at the spped of light will exit the atmosphere very quickly if not interrupted by an atom molecule that can absorb its energy The energy of the photon can not be said to be in the atmosphere in the sense that it does not contribute to the temperature of the atmosphere Once the photon is absorbed you are right that this energy is quickly distributed amongst large number of molecules by collision Surely this would raise the overall average temperature slightly If I understand your argument correctly you are arguing that the global mean surface temperature is unaffected by the molecular composition of the atmosphere Therefore if there were no CO2 or 10XCO2 would have no affect on the energy balance This simply isn t the case We know this because we have the example of the Moon without an atmosphere but with the same amount of incident solar radiation to compare to If you increase the quantity of something that is keeping you warm in this case CO2 you will get warmer two blankets instead of one 23 Timothy says 28 Oct 2005 at 5 01 AM Re 20 Wayne I haven t heard about NOAA s forecast but I have heard about the Met Office forecast for a colder than normal winter for the UK The key part of the Met Office forecast is an NAO forecast that predicts a strongly negative NAO less cyclonic activity over the UK less heat transported north by the cyclones colder than normal UK This heat has to be somewhere else which will therefore be warmer than normal Incidentally the seasonal forecast model doesn t show this signal convincingly This might be because it isn t able to generate sufficient blocking anti cyclonic activity as many GCMs suffer from this failure It the seasonal forecast model would therefore not be picking up the strong negative NAO that is being forecast I believe the NAO forecast is made simply by a statistical relationship between a North Atlantic SST anomaly pattern in the summer and the following winters NAO index It is however quite a strong relationship as it has been used quite succesfully as a hindcast for the historical record of the NAO 24 Tom Fiddaman says 28 Oct 2005 at 7 25 AM Re 16 etc By this line of reasoning water vapor would also have no greenhouse effect It may be hard to detect 2 degreeC decadal trends but I think a 30 degree absolute difference between theory and reality might be noticeable especially when the oceans froze over 25 Andrew Dodds says 28 Oct 2005 at 9 29 AM Re 16 18 19 John Please stop dragging the family name down 26 Lee A Arnold says 28 Oct 2005 at 9 56 AM Re 16 Correct me if I m wrong but I thought that any CO2 intercepts infrared radiation arising from the sun heated EARTH S SURFACE and bounces it around before it is finally lost to outer space More CO2 bounces it around more before it is finally lost to space More bouncing equals higher temperature 27 John Dodds says 28 Oct 2005 at 12 21 PM Rebuttal to 21 etc relating to 16 18 YES I am claiming that there is no such thing as a Greenhouse effect CAUSED by GHGs which includes CO2 AND Water vapor Response In that case we can stop there Find yourself some web space or a newsgroup but don t spam your pet theories here please A brief link to your exciting new reseach should suffice for those interested William 28 John Dodds says 28 Oct 2005 at 12 43 PM Re 26 The radiation is radiated from any material depending upon its temperature Stafan Boltzman law both the ground and the air radiate The concept of MORE CO2 means more bounces means more temperature is wrong The limiting factor is the radiated energy not the amount of CO2 You can only transmit the amount of energy that is radiated The sun solar in energy dictates how much energy comes in gets absorbed by the air and ground and is then radiated out to be absorbed by the GHGs and returned to the air or space Regardless of how many GHGs you have the total energy transmittal is limited by what the sun puts in You can NOT absorb more energy if there is no more energy to be absorbed AND if the GHGs return the energy to the air by collisions in microseconds with no addition or loss of energy then it doesn t matter how many GHGs there are They are a neutral transfer agent Conservation of energy means that any absorbtion took energy out of somewhere in our case from the ground and air and since the GHGs return the energy to the air which warms the ground there is a net NO change in the energy of the air and the temperature regardless of what you do to the GHGs and NO global warming by changing the GHGs BUT global warming still exists Response Its fairly easy to demonstrate this is wrong Consider a simple situation in which short wave SW radiation R W m2 comes in to an infinite planar black body Then the temperature at equilibrium is given by R eT 4 and T R e 1 4 Now consider the situation where an absorber is present transparent to SW but opaque to long wave IR above the surface The absorber and the surface warm to Ta and Ts The absorber radiates in IR Ra up and down Ra eTa 4 the surface radiates in IR Rs eTs 4 all at equilibrium Now the radiations must balance hence Rs R Ra and 2Ra Rs hence Ra R and hence Rs 2R hence 2R eTs 4 so Ts 2R e 1 4 which is 2 1 4 bigger than without the absorber You can generalise this to multiple levels and to make the absorber only partially opaque and you find that Ts increases with opaqueness William 29 wayne davidson says 28 Oct 2005 at 2 19 PM 23 Thanks Timothy Met office projections you ve stated look sound there is a lack of clashing hence movement between cold and warm air masses because it is extremely warmer in the Polar region It will take a wide spanning quasi static massive high North of Alaska clearing clouds just to bring down temperatures a great deal say to normal winter temperatures around here I measure the absolute density of Arctic Ocean atmosphere and it is quite thinner than previous warm years at about the same dates The official North American statements I have heard from the radio were perplexing the heat is here radiance rates are constant I don t see a cold winter coming at all 30 John Dodds says 28 Oct 2005 at 2 55 PM Response Very long exposition deleted This is not the place to dump your pet theories Get your own website or post to a newsgroup please don t spam us William 31 John Dodds says 28 Oct 2005 at 5 29 PM Very sorry William 26 30 crossed in internet space The full explanation of why I believe Arrhenius is wrong and why global warming is caused by the sun is available at http www geocities com doddssanford sbcglobal net Arrhenius is Wrong html John Dodds Response URL corrected Now thats all jolly good please don t post again on this William 32 Blair Dowden says 28 Oct 2005 at 8 28 PM This discussion gives me a chance to ask a few basic questions When a greenhouse gas molecule absorbs infrared energy what portion is translated into molecular motion thus increased temperature sorry John compared to that re radiated Is there any pattern to the wavelength of the re radiated energy ie usually longer or shorter And how much re radiated energy is absorbed by the ground directly causing surface warming 33 John Dodds says 29 Oct 2005 at 12 01 PM Re 21 The microwave analogy is confusing the issue I would prefer to please stick to GHGs and energy BUT since you brought it up The MW analogy is wrong in that the food ONLY heats up because the MW generator adds energy from the outside just like the sun The energy in the air in the MW Oven will not heat the food above ambient In fact lets take some GHGs a bowl of water and a volume of CO2 in a plastic container and add it to a microwave oven that emits energy in the frequencies that water CO2 absorb The GHG concentrations increase inside the microwave Does the temperature of the water or CO2 increase Will it come to a temperature that is higher than the equilibrium of the air in the MW before you add the two containers Answer NOT until you push the button to add extra energy from the external microwave generator Why not you just added enough of the extra CO2 to absorb all those 900K photons to heat it to way past boiling Could it be that it is the energy that comes into the system ie the sun is that dictates the temperature and the if the air density doesn t change then the type of constituents in the air can NOT change the temperature regardless of their ability to absorb return energy John Dodds 34 John Dodds says 29 Oct 2005 at 12 19 PM Re 31 I suggest you read comment 26 http www realclimate org index php p 193 comments from Eli Rabett who seems to be the local expert in this area This MAY help or confuse even more I found it very informative As for the sorry John comment I do not dispute that adding energy will increase the temperature obviously it does this is what collisions are all about What I dispute is that there is any extra energy available to be absorbed by the added CO2 Where does it come from All the suns energy was previously being absorbed by the preexisting CO2 at the preexisting equilibrium By adding CO2 we do NOT add energy to the system 35 John Dodds says 29 Oct 2005 at 4 51 PM Re 34 which is trying to respond to what is now 32 Blair Dowden request Whoops Sorry wrong address to go to Please try Eli Rabett comment 26 at http www realclimate org index php p 168 comments where he discusses the whole absorbtion energy return subject the discussion subject was Climate Sensitivity aerosol forcing 36 Blair Dowden says 29 Oct 2005 at 11 42 PM None of the sun s energy is absorbed by carbon dioxide Some of the infrared energy radiated by the Earth is absorbed by CO 2 and other greenhouse gases the rest escapes into space Each greenhouse gas absorbs energy in a few wavelength bands and only a part of the energy in those bands generally proportional to the logarithm of the gas s concentration at the concentrations found on Earth For example Venus actually receives less solar energy than the Earth because its albedo is twice as high Yet its average temperature is 470 o C compared to the Earth s 15 o C The carbon dioxide is adding energy to the Venus system by preventing the escape of infrared radiation from the surface of Venus This is basic physics established long ago and not even questioned by any of the scientifically literate skeptics I am hoping someone more expert in this area can answer the questions I asked a few comments ago Response Exactly right and very clear Thanks for this We don t have time to get into discussions of all the non issues that are occasionally brought up in the comments Stefan 37 John Dodds says 30 Oct 2005 at 1 58 AM Regarding William s Response below to Comment 28 and 16 and 6 in the blog http www realclimate org index php p 193 comments Modeller vs Modeller Response Its fairly easy to demonstrate this John Dodds contention that Greenhouse gases or GHGs do not cause global warming is wrong Consider a simple situation in which short wave SW radiation R W m2 comes in to an infinite planar black body Then the temperature at equilibrium is given by R eT 4 and T R e 1 4 Now consider the situation where an absorber is present transparent to SW but opaque to long wave IR above the surface The absorber and the surface warm to Ta and Ts The absorber radiates in IR Ra up and down Ra eTa 4 the surface radiates in IR Rs eTs 4 all at equilibrium Now the radiations must balance hence Rs R Ra and 2Ra Rs hence Ra R and hence Rs 2R hence 2R eTs 4 so Ts 2R e 1 4 which is 2 1 4 bigger than without the absorber You can generalise this to multiple levels and to make the absorber only partially opaque and you find that Ts increases with opaqueness William JOHN DODDS Response The William response to 28 is the standard Arrhenius based proof that adding CO2 GHGs causes warming or the greenhouse effect It is available in most high school or college courses and text books eg http www ldeo columbia edu kushnir MPA ENVP Climate lectures energy Greenhouse Effect html I claim that this mathematical model of GHGs causing global warming is INCORRECT The model fails to conserve energy First an infinite planar black body in reality does NOT represent the earth it should be a spherical black body of earth radius Did Arrhenius believe in a flat earth The flaw is the statement Now the radiations must balance hence Rs R Ra and 2Ra Rs hence Ra R and hence Rs 2R The Conservation of Energy Law requires that ENERGY must balance not the fluxes R Ra etc or energy per unit area You MUST include the total area of the fluxes at the surface or at the absorbing layer etc If you do this then you get the standard R squared dependence of the flux that everyone knows about The flux at the ground is larger than the flux at the energy in equals energy out equilibrium point 10 000m Gravity also forces the density of the air to comply with the R squared dependence Since all the GHG absorbed energy is transmitted to the air by the molecular collision mechanism ie all air molecules are at the same global annual averaged energy temperature at a given elevation then you get a higher air temperature at the ground 288K 15C 59F than at an elevated point 255K 10 000m This works even if there are NO GHGs and the energy transport mechanism from the ground up is convection or conduction This works underground in gold mines or at the center of the earth where the temperature is higher due to the decreased radius but there are no GHGs This works on the surface of Venus where the atmospheric pressure density is 90 times that of earth If you use the hence Ra R conclusion from Arrhenius and William above then the energy in from the sun R times the ground surface area does NOT equal the energy out Ra times the absorber surface area effectively at 10 000m the radiation equilibrium point Because the area of the sphere at the 10 000m level is larger the total calculated energy out would be larger and we would NOT conserve energy THIS IS IMPOSSIBLE The mathematical derivation has created the energy that is attributed to the GHG absorption and to the GHG Forcing in the computer models The GHG Forcing which predicts that GHGs are the most significant cause of global warming is thus an erroneous and artificial mathematical creation of the Arrhenius et al modeling of the greenhouse effect Intuitively if ALL the sun s energy less albedo is assumed to hit the ground or spherical black body ie Energy R flux times ground surface area and is then radiated up as long wave or IR then as the height or radius increases the total energy going out ie R at the height times the area at the varying heights is constant Conservation of energy This means that any Ra down flux that is artificially created by GHG energy absorption MUST have an energy value of ZERO or else there is no conservation of energy Besides if the sun dictates that the Flux energy at the surface is R then where can we get the extra energy to also make the surface flux or Rs 2R or twice as much as indicated in the Arrhenius based derivation above You can t pull the extra energy out of thin air GHGs do NOT create or absorb extra energy to warm the planet They simply transfer the suns energy at ground level to the air to space with 100 efficiency no gains no losses Arrhenius was wrong With no CO2 GHG induced warming there is no need for the Kyoto treaty and any CO2 reduction schemes or CO2 emissions monitoring and trading or for much of the GHG research See http www geocities com doddssanford sbcglobal net Arrhenius is Wrong html for a more detailed explanation that also identifies why global warming still exists but is caused by the sun over which we have little control John Dodds c J Dodds San Francisco Ca USA 29Oct2005 Reproduction permitted with appropriate reference to the John Dodds GHG Letter of 29 Oct Response Of course energy is usually not created from just air assuming no nuclear reactions but its level is given by the total solar irradiance from the Sun Although the sun is bright and looks yellow the so called black body theory can sucessfully be applied to it s surface photosphere to infer the surface temperature on the Sun approx 6000K The black body radiation gives a so called conituoum spectrum a light with a wide range of wave lengths and whose peak is given by Wien s displacement law l a T This is standard physics The long wave radiation from the Earth is also

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