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  • Atlantic circulation change summary « RealClimate
    new study Today the last day of the official 2005 Atlantic Hurricane season might be a fitting opportunity for them to do so Chip Response What we were criticising was Gray s dogmatic insistence that hurricanes were definitely linked to the THC when he has no independent evidence whatsoever that the THC was strongly increasing As the above linked article shows there is a lot of uncertainty in what is going on to sea surface temperatures in which both natural cycles and global warming play a role and absolute insistence that either player must be negligible is unsupportable I would still like to see him make that statement gavin and mike 5 Mauri Pelto says 20 Jan 2006 at 1 16 PM Gavin That was my understanding that most of the freshwater addition was in the North Atlantic Has salinity increased with higher SST in the origination are of the Gulf Stream as well which would increase the north south surface density gradient Response Density gradients appear to be remarkably stable since the salinity changes have been compensated to a large degree by temperature changes That is saltier water is also slightly warmer and the freshening water is also getting cooler gavin 6 Pete Best says 20 Jan 2006 at 1 42 PM Let me attempt to get this straight The Sun heats the earth and ocean at the equator and everywhere else and this in turn heats the atmosphere Evaporation from the oceans is not happenning faster as the amount of energy from the sun is constant but we are saying that due to increased CO2 levels the water vapour is increasing relative to the amount falling back to earth due to the atmospheres ability to hold more water vapour So in effect the seas are becomming saltier around the equator Now further north where the water vapour goes we get more precipitation than evaporation and because more fresh water is falling then indeed over time the northern seas are becomming fresher Now get me if I am wrong but this sounds like the fundamental reshaping of a complex interplay between heat and water transfer between the equator and the sub tropical and polar regions to me or am I overeacting 7 Lynn Vincentnathan says 20 Jan 2006 at 1 48 PM I read last year about findings that plankton sea life in the Atlantic had decreased in some areas due to less overturning or churning of nutrients I think due to thermohaline decline So even without an ice age there are other problems I also read some 15 years ago about a plankton decline in some area of the Pacific due to warmer waters with concomitant fish decline Eventually we need to get all the various reports even those not related to GW such as those dealing with regular pollution and get a better picture of it all 8 JohnLopresti says 21 Jan 2006 at 3 39 AM The Woods Hole Institute graphic Curry et al reminded me on macro scale of several factors pertaining to buffered solutions and their exceptional propagation of electromagnetism compared to fresh water additionally looking at the ocean as a fairly confined liquid mass I would look for the effect induced by the eastward force of the planet s westward rotation Also the ice cap melt entering from polar portals shows nicely in the WHI progression of diagrams 9 Dietmar Temme says 21 Jan 2006 at 12 59 PM Quote The most complex computer models of the climate and oceans the sort used to make climate predictions for the Intergovernmental Panel on Climate Change IPCC suggest that the flow might be expected to slow by an average of 25 by the end of the twenty first century but not to shut down completely The crucial word is average From paleontology there are well documented Heinrich Events at the end of some ice age indicating an oszillating behaviour between an Europe under ice and free within small periods of time So the question is can by very hot summers and unusually warm winters cf news from Spitzbergen the THC shut down for a season or two Response You probably mean Dansgaard Oeschger events not Heinrich events But I think you ve been misled by the term rapid D O event onset may be fast but they last for quite a time there is no way to fit them into a season or two William 10 David Bassendine says 21 Jan 2006 at 4 16 PM Re 3 Gavin you say that a decline in the Atlantic THC will most probably moderate the rate of warming in Europe I suppose you are talking about annual means here but would such as slowdown also cause changes in seasonality towards a more continental climate i e more extreme winters as the oceanic contribution to heat transport diminishes Response You generally see a bigger effect in winter so an increase in seasonality could be expected but for the future projections a more rapid warming of summers is the more likely expression of that I haven t seen any results that suggest that winters will get colder even as the annual mean temperature increases This is really a function of the rate of change though for the moderate slowdowns that the models project for the future this doesn t happen in 8 2 kyr event simulations for instance it does gavin 11 Hank Roberts says 23 Jan 2006 at 3 30 PM Gavin s for instance link in his reply above is to the abstract I recommend going to the Science Brief page you can reach via that abstract http www giss nasa gov research briefs legrande 01 This is Gavin edit me if I m misreading this please I m just an amateur reader a test of a climate model to see how well it could simulate the well known brief climate change event 8000 years ago when the big North American glacier receded and its meltwater lake spilled into the North Atlantic As Gavin says that reconstruction modeled a change much like the real climate did change modeled Europe gets modeled cold as real Europe got cold due to sudden large inputs of cold fresh water to the North Atlantic Lonnie Hancock quoted in Thin Ice says the same thing Gavin does above that we don t expect cooling in the immediate future today with no huge lake behind a melting glacier about to bust loose fresh water has to melt from ice or fall as rain to dilute the North Atlantic salt water But a slowdown in the Atlantic circulation could reduce the speed at which Europe heats up for a while and have other consequences The Science Brief shows how nine different models are in fair agreement about the past 1850 present Atlantic circulation and how they differ in modeling possible futures through 2100 http www giss nasa gov research briefs legrande 01 fig2 gif This is good info congratulations to whoever writes the Science Brief pages It makes one think and gives enough footnotes and references to pursue this I m basing comments solely on the Science Brief and reading as a nonscientist here it just seens a very interesting perspective to be able to start testing models against this fairly well known event 8000 years ago and getting useful results Response My student Allegra LeGrande and I wrote the Science Brief but I recommend reading the full paper it s not that obscure gavin 12 Lynn Vincentnathan says 24 Jan 2006 at 5 41 PM Okay maybe the North Atlantic Europe will only cool a bit if at all from a THC slowdown halt due to the GW offset but where does that leave me lat 26 S Texas near the Gulf of Mexico If the world is warming on average and some places cool at bit then that means some other places might really sizzle Would it get a lot hotter here sort of like the Arctic enhancement effect Could we be going from 112 degree F days to some 120 degree days Of course I wouldn t expect it in my lifetime 13 Almuth Ernsting says 25 Jan 2006 at 2 01 PM The present cold spell in Europe probably just shows how a rare event severe winter weather has on the whole become in Europe and might support the Met Office s guess that rising SSTs are in the long term making the North Atlantic Oscillation ever more strongly positive in winter I think last May SSTs in the Azores were a bit more like they had been in 1995 which whereas on the whole they are rising In any case Scotland would cool quite a bit if the THC weakened significantly and quickly and our primroses and forsythia have been blooming just nicely for weeks Anyway I just wondered if the THC really was quite suddenly starting to show ie if what Wadhams and Bryden found was both accurate and the beginning of a new trend which the Nature article says is unlikely what would that look like on a weather chart Obviously more temperatures below zero in the winter Would it actually show itself in terms of the winter NAO becoming first less positive and soon more strongly negative less hot air from the tropics pushing over Europe and in a more northerly and easterly winds developing Would it show itself in more and more intense droughts developing over countries like Kenya Tanzania Rwanda Burundi Almuth Ernsting 14 Bill Settlemyer says 26 Jan 2006 at 8 06 AM As a journalist living on the Southeast U S coast I m following climate change issues with considerable interest I ve read a great deal about the possibility of changes in Atlantic circulation popularly described as the conveyor belt All of the writing in the general press has been about how cold it could get in Northern Europe but no one seems to have commented on whether there would be an opposite effect at the southern end of this circulation Would there be a corresponding increase in average temperatures Response Models suggest a slight increase in the Southern Atlantic but it s not as significant as in northern cooling see the figure in Stocker 2000 for some idea gavin 15 Steve Bloom says 27 Jan 2006 at 10 27 PM Re 4 Folks following the hurricane controversy involving Bill Gray may be interested in the exchange documents Judy Curry of Webster et al has posted on her web site http www eas gatech edu research candr htm I can t tell for sure but it appears that the Gray comment may have been submitted to Science in hopes of publication Since the Webster team s response left Gray with no leg to stand on publication may be unlikely In any case it s an interesting read 16 Tom Brogle says 30 Jan 2006 at 3 37 PM I ve been looking at https www fnmoc navy mil products NCODA US058VMET GIFwxg NCODA glbl sst gif https www fnmoc navy mil products NCODA US058VMET GIFwxg NCODA glbl sstanomaly gif These clearly show the tne Gulf Stream pentrating the Arctic as far as Novaya Zemblya If the Gulf Stream was weakening surely it would be shortening as well 17 Brian Forbes says 31 Jan 2006 at 8 18 AM The Gulf Stream is the major carrier of heat from the sub tropics to the Arctic If is has slowed down substantially why is Arctic melting accelerated The two statements contradict each other If the Gulf Stream has collapsed to the extent they say it has it should have caused the Arctic to cool Something is WRONG Response See our comments here gavin 18 Dan Welch says 31 Jan 2006 at 2 37 PM Forgive me if this is a naieve question but is it possible that slowing down or shutting down of the North Atlantic conveyor could offset temperature rises from global warming to the extent that this would stop the melting of the Greenland ice cap To the lay person media reports seem to alternately present the danger of plumetting temperatures in northern Europe as a knock on effect of increased fresh water melting from the Greeland ice and the danger of sea levels rises due to increased temperatures melting the Greeland ice but I am struggling to find speculation on how the two might interact Response Fair enough point In the model scenarios where there is a slow down in the circulation the relative cooling of the area compared to the rest of the world is not sufficient to actually cool Greenland and so Greenland continues to warm albeit at a slower pace than if the circulation hadn t changed gavin 19 tom brogle says 1 Feb 2006 at 4 38 AM RE response to 18 So Greenland will carry on melting when the rest of the Arctic gets colder as the THC slows down Are you sure 20 Brian Forbes says 1 Feb 2006 at 5 07 AM re response to 17 It does not invalidate my point I quote from the article it is a long way from the Greenland Sea to the Gulf Stream It is even longer way from Novaya Zemblya which is at the end of the tongue of water that juts into the Arctic to the north of Russia I surmise that if the GS NAD had slown down then this area would have shown signs of it It does not appear that it has 21 Eric Swanson says 1 Feb 2006 at 1 51 PM RE 16 and others Here s another look at SST s http weather unisys com surface sst anom html Note the rather warm pool south of Greenland and the cold pool off Norway That s been there for several weeks now so one is left to wonder whether the lack of convective chimneys reported by Peter Wadhams last Spring may have been the cause http www realclimate org index php p 159 The rather warm area seen in the NAVY graphic for the Barents Sea may be the result of processing of the data Areas which happened to exhibit sea ice during the base period used to calculate the anomaly but which now are free of sea ice will appear to be much warmer to satellite instruments Of course if the sea ice is melting this may be an important realization A comparison of NH sea ice extent with last year may be found here along with data for previous years http polar ncep noaa gov seaice Analyses html akmap 22 Brian Forbes says 2 Feb 2006 at 7 20 AM Re 21 http weather unisys com surface sst anom html is interesting it shows that the oceans of the Southern Hemisphere are mostly cooling quite substantially in places Does this show up on your models Response An instantaneaous snapshot no The longer term trends which are warming yes gavin 23 Brian Forbes says 2 Feb 2006 at 4 01 PM Re Gavin s comment on 21 Well then it does not show the long term trend in your hot and cold spots in the N Atlantic I d rather accept the official navy wersion 24 Hank Roberts says 4 Feb 2006 at 4 10 PM Brian the Unisys page goes back six days Is there some Navy page you found you meant to refer to that shows long term trends and that doesn t show warming Here s a deepsea question http sfgate com cgi bin article cgi file chronicle archive 2004 03 01 MNGEL5B7VE1 DTL That s a year old mentions a tiny fraction of a degree centigrade warming in very deep water that wasn t expected to show global warming effects Volcanos are ruled out they are too scattered to warm this whole expanse 25 Brian Forbes says 9 Feb 2006 at 7 12 AM Hank I read the article The upwelling in the N Pacific is the other end of the downwelling in the N Atlantic http www grida no climate vital 32 htm How long does it take for the journey 8 years highly unlikely 80 yrs I doubt But 800 yrs brings us back to the MWP which certainly affected the N Antlantic The navy page has shown a slow warming of the N Hemisphere and a slow coolng in the S Hemisphere for the last 2 years It doesnt show the hot and cold spots as on Unisys I know the basis for the navy differential temperatures Enquiries to Unisys as to the basis for theirs have been ignored So I trust the official navy site to be truthful rather than an apparently commercial organisation 26 smyyga says 9 Feb 2006 at 11 00 AM This is indirectly related to the issue at hand Here are the presentation slides of Eric Rignot about the mass balance of the whole Greenland ice sheet I brought up some of his results on realclimate in December http earth esa int workshops fringe2005 participants 698 pres 698 Rignot ppt files frame htm 27 Nigel Williams says 13 Feb 2006 at 7 59 AM Brian You make a stab at the total journey time for an element of water to complete the circuit of the THC and relate that process to the swings in N H and S Hemisphere warming I suggest that the more significant figure is the travel time for a deep water wave to do the circuit of the THC This is important as it defines the rate of propogation in any change in the impetus of the THC A drop say in the driving head at any point in the THC will propogate as a wave travelling at something over 700kph assuming an average depth of 4000m This will take about 90 HOURS to run the full 65 000km or so circuit of the THC Thus any event altering the drive of

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  • Ocean heat content: latest numbers « RealClimate
    over ocean is stronger than over land resulting in an ocean to land ratio of 1 3 Some of the strongest forcing is located off the coasts of east Asia Europe and northeast United States As a result of persistent marine stratocumulus the oceanic regions off the west coasts of Africa and North America are responsible for the rest 59 Ferdinand Engelbeen says 23 Aug 2006 at 7 48 PM Re 55 57 Catched by the speed of the blogosphere Indeed I was referring to Kristjansson thanks Martin who indicated a good reverse correlation between low cloud cover and TOA solar radiation but worse for GCR galactic cosmic rays In the longer term there was 1985 2000 a decrease of high cirrus cloud cover over the sub tropics caused by faster Hadley Walker cell circulation leading to more insolation 2 3 W m2 and more escape of heat to space 5 W m2 See the works of Wielicki 2002 and Chen 2002 This was expanded by J Norris 2005 in time back to 1952 for sea level clouds and 1971 for land based clouds and in latitude by surface based cloud observations The change in radiation balance is more heating of the oceans at one side specifically high in the subtropics as expected but more heat released at higher altitudes thus somewhere acting as a net negative feedback to higher sea surface temperatures Further the change in radiation balance is huge some order of magnitude larger than what can be calculated from the theoretical increase in LW reradiation by the increase of GHGs in the same time frame Even with water vapor feedback this can not be explained Now we probably see some reversal of the previous warming of the oceans So my first thought was clouds as these can give huge changes in radiation balance in a short time Regarding fine aerosols as suggested by David there are huge increases in industrial activity in SE Asia since 1975 but that is a rather linear expansion where SO2 emissions are in lockstep with more dirtier aerosols As far as I know the rate of increase of the emissions didn t change much in last years therefore I don t think that man made aerosols are responsible And I have not read of extreme conditions for natural aerosols Mongolean desert either But I have to admit that I didn t digest yet all the links about aerosols that David send to another list UKweatherworld The solar cloud connection is quite real after two satellite measured sun cycles but can t explain the rather fast and huge changes in radiation balance over the previous period There may be self sustaining internal oscillations which feed the changes in SST air circulation cloud cover radiation balance back and forth AMO But this needs to be resolved 60 Steve Sadlov says 23 Aug 2006 at 8 09 PM Some of the strongest forcing is located off the coasts of east Asia Europe and northeast United States In the case of Asia one must consider both the Chinese dust storms as well as the many power plants and other industrial facilities burning high sulfur coal with no stack scrubbing whatever 61 Ferdinand Engelbeen says 23 Aug 2006 at 8 12 PM Re 58 Unfortunately GCM s don t provide data Based on the decrease in SO2 emissions in Europa there should be a huge difference in temperature increase between less polluted areas and more polluted areas downwind from the main sources But that is not measurable see here Based on the increase of aerosols in SE Asia one should expect less warming in the NH Indian Ocean than in the SH But that doesn t fit reality see here And aerosols off the Chinese coast should induce more reflecting longer lasting clouds but there was a decrease of cloud cover in the 30N 30S band with increasing aerosol releases I have no specific figures for the Eastern Pacific And last but not least ocean heating is larger for the NH part if corrected for area while most anthropogenic aerosols are released in the NH and most stay there until raining out 62 John L McCormick says 23 Aug 2006 at 11 06 PM China s coal fired electric generation stations emitted 26 million tons of sulfur dioxide in 2005 Prior to the 1990 US acid rain program implementation American generating stations emitted 24 million tons of SO2 and current emissions are about 10 5 million tons 63 david morgan says 24 Aug 2006 at 4 28 AM Here is what we must assume 1 Conservation of volume aka sea level during energy loss 2 Heat transfer to space without massive heat transfer to intermediate atmosphere 3 Heat transfer to space directly by water vapor Seriously 4 Release of massive amounts of water vapor that then somehow does not behave as a greenhouse gas Or we could look again at the map on page 11 It is very hard to miss the blue line from the tip of africa to tasmania This is part of the MOC In fact you ll see the rest of the MOC outlined in red and blue What could cause this The MOC streams could be diverging and resistance to it increasing as it diverges As it diverges it mixes with the surrounding water Here is Josh Willis one of the authors on the issue it is true that transport of heat to deeper layers my be a part of the signal MOC shutdown but in my opinion the magnitude and speed of the cooling are too large to be entirely explained this way The upper 750 m of the ocean cooled by about 3 x 10 22 J in 2 years This is equivalent to a heat flux of about 0 48 pW or a circulation change of 116 Sverdrup degrees C The difference in mean temperature above and below 750 m is about 7 7 degree C That means that in order to achieve a sufficient downward heat flux the circulation would have to change by 15 Sv more or less instantaneously and remain that way for 2 years 15 Sv is the same order as the mean magnitude of the overturning circulation itelf That would mean that the entire MOC would have had to have shut down instantaneously in 2003 and remained shut down for the past two years This conflicts with Harry Bryden s estimate of the MOC that he published in Nature last year which he computed to be about 15 Sv from his hydographic cruise in March of 2004 Sure but the requirements are much less if you use the much cooler temperature of the deep MOC currents and not just the below 750 m temps Michael Winton has also suggested another possibility He postulated that upward thermal buoyancy flux induced by surface cooling could become insufficient to overcome the stratifying effect of surface freshening creating a thermal inversion in the oceans Visually it would probably have an effect like the north atlantic as pictured on page 11 64 Ferdinand Engelbeen says 24 Aug 2006 at 6 21 AM In addition to the clouds item J Norris has a paper in preparation about cloud trends vs climate change On page 58 there is a calculation of cloud feedback assuming that the change in cloud cover is solely a response to increased forcing The net response is 0 8 which is a very strong negative feedback Of course this is the response if nothing else is influencing cloud properties cover but important enough for further investigation The paper in preparation gives a very detailed overview of cloud properties and influence and observed SSTs over time Of interest are pages 62 and 63 where cloud cover changes roughly coincidence with SST changes 65 ike solem says 24 Aug 2006 at 3 15 PM Okay back to radiative imbalance The only way the Earth can lose heat to space is via radiation but the redistribution of heat within the oceans atmosphere and ice sheets can occur via conduction convetion and radiation Under steady state conditions the total radiation absorbed by the Earth must match the total radiation emitted by the Earth that s what radiative balance or imbalance means in the climate literature This is a very different notion than that of a model of radiative absorption and emission in the atmophere which is a very specific physical process See the discussion of the microwave satellite temp measurements a major discussion that was initiated by climate skeptics who claimed that the satellite record showed tropospheric cooling at Realclimate http www realclimate org index php archives 2005 08 et tu lt The internal heat transfer beween the oceans atmosphere and ice sheets can be modelled far easier than it can be measured but models need real data for comparison To account for their results the authors Lyman et al suggest radiative loss to space but they also include references relating to warming bottom water deepening tropical gyre warm bowls and increased mass loss from the Antarctic and Geenland ice sheets They acknowledge that the altimetry data seems to contradict the notion of radiative heat loss to space Looking at their global map it seems that the majority of the cooling was from fairly isolated regions centered around 30N and 30S One thing I would have liked to see in the paper is a quantitative side by side comparison of sea surface temperatures and upper ocean heat content all the paper says is that only a small amount of cooling is observed at the surface although much less than the cooling at depth though they do report that it is consistent with 2 yr cooling SST trend but again no actual data analysis of the SST trend is reported This seems sloppy to me since the SST dataset is far more reliable than the upper ocean heat content dataset and as far as I can tell the Arctic is underrepresented in the data The global ice free ocean seems to exclude the Artic and Antarctic ocean regions since ARGO floaters wouldn t be likely to survive the sea ice which is why remote bottom moored data collection systems are a good idea esp for the Arctic I d like to see a global map of SST next to their global map of OHC that might reveal patterns of interest Limited data from the Arctic and Antarctic the regions that are expected to warm the fastest and the earliest means that warming in these regions could have offset the rest of the reported trend The fact that the cooling trend is reduced when the ARGO data is excluded seems to support this notion Incidentally I just found that the Reynolds SST weekly report has been removed from the NOAA website here is the old location http www cdc noaa gov Datasets reynolds sst I ve been looking at that on a weekly basis for years and now it s suddenly gone There is something odd going on at NOAA and NWS as far as I can tell perhaps the climate denialists have found a new home in the federal government I d very much like to know why that page has been removed So the loss of heat from the upper ocean could be an artifact of undersampling in polar regions I also don t understand why the authors didn t separate out SST s and apply their statistical method to that dataset as well as to their complete ocean heat dataset How have SST s changed in polar regions Furthermore their globally averaged depth profile something I ve never seen before of ocean heat content is remarkably devoid of any practical information a latitudinal display at every 10 degrees would be more useful In general these datasets are supposed to be made available for analysis by other researchers and there was no mention in the paper of access to the actual data used It would be nice to see a global map of data density next to the OHC global data map While restricting access to raw data is common practice in pharmaceutical industry research this should definitely not become the standard for climate research Even assuming that the dataset is comprehensive Considering that the upper ocean cooling is seen mainly at 30N and 30S another explanation for this cooling is increased ocean to atmosphere heat transfer in these regions possibly aided by hurricane mixing of the upper ocean layer and advection of deeper cold water as a result If so then it could be that the heat was lost to space but given the rapid redistribution of heat in the atmosphere via convection isn t it also possible that the heat was transferred to the ice sheets resulting in increased freshwater runoff to the oceans What makes this scenario unlikely Response One minor point As far as I understand it hurricanes actually warm the deeper layers though they do temporarily cool the surface which adjusts through air sea exchange very quickly after the storm has passed This is because even the cooled surface waters that are mixed down are still much warmer than the thermocline waters gavin 66 L David Cooke says 24 Aug 2006 at 10 24 PM Ref 59 Ferdinand My apologies for stepping in earlier I was trying to bring into the discussion your earlier comment regarding the effect of lack of saturation in the Arctic regions from UKweatherworld And to share that I am seeing aerosols as a significant participant however not the SO2s as much as the SiO In the period of 2001 through 2004 I had observed a very interesting trend in the character of aerosol precipitants along the Eastern Divide of the Appalachian Ridge A very fine aerosol that appeared to be almost like talc was faily widespread throughout Western NC At first I thought it was simply dust due to development work in the area I hung several tape strips across a wide area of NW N Carolina and got some interesting data not only was the aerosol very fine but about 1 2 of the aerosols appeard to have a spherical character to them As I did not have an outlet to share this information I had simply reserved it as a personal observation It was not until the NASA study regarding the Sahara Dust in Florida that I thought about it again I wish I still had those samples It made me curious if there might not have been a relationship to the volcanic activity in the Caribbean in the late 90 s and the possible character of the hydrologic cycle in the early 90 s That most aerosols precipitate out in only a few years was clear but what happens to the aerosols that reach the Tropopause and lower Stratosphere if they are very fine The question became Is it possible that these very fine aerosols were responsible for the change in the hydrologic cycle in that the state change and the normal saturated adiabatic adaibatic cycle could be interrupted And that was the balance of the links I had shared with you in reference to the effects of areosols When you and Ike began discussing the the Energy Imbalance and you mentioned the missing heat it brought back the question of what if there is an interruption to normal water vapor latent heat transfer and it is not corrected in the models As you are pretty busy I had not thought to pursue this with you earlier but here there be an opportunity Has anyone seen anything that would seem to support my observations Note I had not seen that the Walker circulation had increased I had seen a study that in the N Pacific it had decreased about 3 Later I have seen what appears to be an indication of an increase of northern movement of the air mass what was dominated by the Walker circulation Coupling this effect with the increasing Arctic Easterlies the warmish high altitude Polar temperatures the NH 250mb isotherm analysis indicating an abnormal increased deviation of the Northern Jet Stream http nomads ncdc noaa gov 9091 ncep NCEP and the broken hydroligic changes all seem to point to a similar process Dave Cooke 67 L David Cooke says 24 Aug 2006 at 10 37 PM Ref 65 Ike I have not seen a 30 N S source for 20 Deg C content isothermic and SSTs However I have a source for around 8 Deg http tao noaa gov tao jsdisplay sel time series ndbc shtml In the Eastern N Pacific the isotherms are getting shallower and the 20 Deg C depth apppears to be getting shallower over the last 3 years at a number of buoys However it is not universal and depending on latitude can be more or less pronounced It appears to be a shallower observation closer to the equator and the further east you measure Dave Cooke 68 llewelly says 25 Aug 2006 at 1 44 AM Incidentally I just found that the Reynolds SST weekly report has been removed from the NOAA website here is the old location http www cdc noaa gov Datasets reynolds sst I ve been looking at that on a weekly basis for years and now it s suddenly gone There is something odd going on at NOAA and NWS as far as I can tell Ike I think the Reynolds SST weekly report is still available here NOAA s web pages appear to be undergoing extensive re disorganization So far everything I thought was gone I was able to find in a different place by dropping the right keywords into google followed by site noaa gov 69 Steve Bloom says 25 Aug 2006 at 4 08 AM RE 65 The GRACE data makes that unlikely The total for Antarctica and Greenland is only about 1 mm yr still a considerable increase from just a few yesrs ago Josh Willis thought that other contributions might bring it to 2 mm yr total 70 Eachran says 25 Aug 2006 at 6 33 AM I find that this particular thread is very interesting thanks to all A question please I understand that ocean circulation is complicated but I have been trying to find out how much is known about the flows of underground rivers and where they enter the ocean Significant flows of fresh water are involved for example one single source with its outlet in the deep Mediterranean is reputed to have sufficient fresh water to supply the needs of Marseilles The technology for supply is like capping an oil well at least that is the way I prefer to look at it It occurred to me that there must be similar flows into all the oceans of the world and particularly from melting ice caps where temperature changes may have exposed previously blocked outlets Are there any maps of the flows of this fresh water or any other information on this subject which is readable and reliable please for a non expert like me I can persist with the idea of run off from land acting as an umbrella as it were but it doesnt seem correct to me Help 71 L David Cooke says 25 Aug 2006 at 8 16 AM Rey Eachran I am actually more familiar with the Florida submarine springs however the last link I provided below indicate a number in the Med as well I did not find any in the Indian Ocean though there are several references to arabian coastal sources I would be inclined to expect a large amount in SE Asia however I have no references Overall I would not expect these to be a profound effect Though there is a large volume most can easily be compared to a large stream or small river Total ground water including the known major rivers that empty into a saline body is likely less then 3 5 of the total volume that evaporates daily whether from land or oceanic sources I hope this can assist you in your endevors http sofia usgs gov publications ofr 00 158 http fulltext10 fcla edu cgi t text text idx c fhp idno SF00000190 format pdf http fga freac fsu edu gaw 2000 resources waterpdf springs pdf http www flmnh ufl edu springs of florida submarine html http water usgs gov ogw karst kigconference pws submarine htm http www jhu edu scor wg112 article htm Dave Cooke 72 Eachran says 25 Aug 2006 at 9 36 AM You are a good man Dave Cooke thanks I understand your point about evaporation but I was also thinking of the impact on undersea currents temperature and salinity I shall read your links and continue Thanks again Anyone else out there with info all gratefully received 73 Alastair McDonald says 25 Aug 2006 at 10 17 AM This link to the US Geological survey site gives you information about ground water dischare There is twice as much ground water as there is fresh water http ga water usgs gov edu watercyclegwdischarge html In fact all rocks except for a small section above the water table are saturated Since water is heavier than oil when an oil resevoir is penetrated the water forces the oil out of the ground causing a gusher I think most of the groundwater enters the oceans through seeps driven by osmosis The salty water draws the fresher water out of the rocks due to the same process that your skin wrinkles in the bath The salty fluids in the skin soak up the fresh bath water See http www loc gov wiseguide jun05 toes html I think you will find that salinity near the coasts is lower than that at the same depth further from shore even at great depth 74 Gary Rondeau says 28 Aug 2006 at 7 34 PM Do the oceans offer an engineering oppertunity Since the ocean component of the climate system has by far the biggest heat capacity I ve been wondering if the cool waters of the deep ocean could be used to mitigate the effects of global warming for a few centuries until we have really depleated our carbon reserves and the system can begin to recover on its own As repugnant as it is to suggest engineering solutions for mans s folly this is one I haven t heard bantied about so please shoot it down IF cool deep sea water were mixed relentlessly with surface water by some engineering method e g lots of wave operated pumps and 800m pipes could that enouromous cool reservoir of water a mitigate the thermal expansion of the oceans because of the differential in thermal expansion of cold and warm water and b cool the atmosphere enough to reduce the other wise expected effects of global warming My back of the envelope calculation suggests that we should be able to do this for several centuries without warming the deep waters very much while maintaining constant surface water temps you need about 100 liters s km 2 to cool present forcings during which time we kick the carbon habit Besides all of the horrible unknowns the biggest problem is pumping that much water up and down 75 Hank Roberts says 28 Aug 2006 at 9 38 PM Gary prior discussion around here has some numbers on the idea http www realclimate org index php archives 2006 06 geo engineering in vogue comment 15112 76 Yartrebo says 29 Aug 2006 at 6 10 PM Regarding comment 74 That would be a horrible idea to attempt even if it is feasible and using OTEC it might be since that will actually generate a little usable energy in the process for at least three very big reasons 1 The colder surface water would mean that far less energy is being lost to space making the energy imbalance even worse 2 Cold water at the bottom of the ocean holds a lot of dissolved carbon and bringing it to the surface will both acidify surface waters and emit carbon into the atmosphere The amounts of carbon would be vast on a scale comparable to current human emissions 3 It would involve messing with the environment on an unprecedented scale and such things generally cause a lot of other effects which we didn t even imagine could happen 77 John Stiff says 30 Aug 2006 at 6 04 PM Gentle Scientists Google and my brother brought me to this page I believe you all have explained the heat loss from the surface of the world s oceans Ideas that I thought of solar cycle now at solar minimum transfer of heat from the oceans to the atmosphere via recent active hurricane seasons and ice melt runoff were all taken One point that was not fully considered was the contribution of the melting of the artic ice sheet It is not only smaller in area but thinner as well This when added to the contributions of the Antarctic continental glacier and Greenland melting should account for the discrepancy It goes without saying that melting ice cools the water 78 Rod Gill says 30 Aug 2006 at 6 33 PM With climate and Greenhouse Gas thoeries of Global warming it appears to me that of most interest is the interface between the Earth s atmosphere and space and the flow of radiated heat from the sun what s reflected back from Earth s surface and the consequences of any change in that balance So what do the Astrophysicists suggest The most compelling arguments to me are from the variablility of the earth s orbit around the sun and the Sun s variable output of radiated energy Based on this energy of all sorts from the sun is predicted to decrease from now until 2030 when it will slowly increase again Since the oceans are massive heat sinks they cause delays around a decade or more in observed temperature changes from changes in radiated energy from the sun The slight drop in net ocean heat from 2003 2005 fits what the Astrophysicists predicted some years ago Some of them have also successfully predicted El Nino phases and some of the recent droughts This tends to lend a certain amount of credibility from my view point as no other branch of science appears to be able to It would be very interesting to say nothing of it being potentially very useful if Astrophysicists and Climate Scientists got together for a brain storming session Is this doable Two links regarding variability of sun s energy and Earth s changing orbit http mitosyfraudes 8k com Calen Landscheidt 1 html http www ngdc noaa gov stp SOLAR solarda3 html 79 Barton Paul Levenson says 31 Aug 2006 at 8 07 AM Re 78 and The most compelling arguments to me are from the variablility of the earth s orbit around the sun and the Sun s variable output of radiated energy I explained in another thread why the Sun can t be doing it To summarize the Sun simply has not grown enough in luminosity to account for the global warming Let me know if you want to see the math 80 Ferdinand Engelbeen says 31 Aug 2006 at 12 31 PM Re 79 Barton may I disagree There are two points in this the sun is since 1940 higher in intensity than ever in the previous 400 years and probably 8 000 years This anyway may explain most of the warming in the 1900 1940 period Second solar intensity on short term is inversely correlated with low cloud cover see the reference here which intensifies the variation and probably the long term trend too If the same happens for GHGs remains to be seen but the trend over the last decades is the other way out for cirrus clouds And even if there is little trend of solar in the past decades there still is some discussion about an upswing in minimum solar strength the impact of the higher than past level of solar intensity is delayed by the oceans and only now may come into equilibrium 81 Hank Roberts says 31 Aug 2006 at 1 40 PM Ferdinand have you an explanation in your theory for why none of the other factors act as forcings during the same time period It sounds like your theory is that somehow only the sun and nothing else contributes to the observed change Do you have a way to show that the rest such as aerosols co2 AGHG somehow sum to zero 82 Hank Roberts says 31 Aug 2006 at 1 44 PM P S I have read http www realclimate org index php archives category climate science sun earth connections and would hope that gets reopened at some point for more discussion 83 Ferdinand Engelbeen says 31 Aug 2006 at 6 05 PM Re 81 Hank I never said that CO2 has no influence at all But I have doubts about the height of the influence as currently implemented in climate models As already said in previous discussions the theoretical influence of doubling CO2 is rather well known based on radiation absorption bands But that gives less than 1 C warming without feedbacks the influence of aerosols is highly uncertain and IMHO overestimated If this is the case then the influence of GHGs including feedbacks is also overestimated or it is impossible to fit the 1945 1975 temperature trend the influence of water vapor feedback itself is positive but clouds seems to act as a strong negative feedback while current climate models see clouds as a neutral to positive feedback the influence of solar variations IMHO is underestimated as these are accompanied with a positive cloud feedback and specific influences in the stratosphere This has implications for future scenario s as a lower sensitivity for CO2 and a higher for solar means that there will be less warming for the same CO2 emissions assuming no large excursions of solar With halve the sensitivity for CO2 1 5 C for 2xCO2 including feedbacks reduced influence of aerosols 1 4th and increased solar sensitivity 1 5 times one can fit the temperature trend of the last century Based on what I have read about aerosols cloud behaviour and solar in my opinion the real response to 2xCO2 may be at or even below the low end scenario of the IPCC 84 Barton Paul Levenson says 1 Sep 2006 at 6 09 AM Re the Sun I ll repeat my calculations here Please let me know if I made a mistake or mistakes The emission temperature of a planet the temperature as measured from some distance away can be found with this equation Te S 1 A 4 sigma 0 25 where Te is in kelvins S is the Solar constant A the Earth s bolometric Bond albedo and sigma the Stefan Boltzmann constant S at Earth s orbit averages 1367 6 Watts per square meter the Earth s albedo is about 0 3 assume this is exact for the moment and sigma has the value 5 6704 x 10 8 in the SI which gives an emission temperature for Earth of 254 9 K Global warming since 1880 or so has been about 0 6 K How much would the Solar constant have to have risen to provide that much of an increase Solving for S we have S 4 sigma Te 4 1 A Plugging our results for Te back into this equation it gives S 1367 9 which shows the problems of using significant digits If we take Te 254 9 0 6 254 3 we get S 1355 1 In other words the Solar constant would have to have increased by 12 8 Watts per square meter to get the observed warming The Solar constant has in fact risen by about 1 Watt per square meter over this time period Solar can t do it alone without violating conservation of energy Now there may be some feedback in the Earth system that multiplies changes in the Solar constant But until the Solar freaks identify what that feedback is their theory fails on basic scientific grounds BPL 85 Ferdinand Engelbeen says 1 Sep 2006 at 4 26 PM Re 84 Barton What you did forget is to include the greenhouse effect Of the 1370 W m2 solar radiation some 240 W m2 is reaching the surface There must be an equilibrium at the TOA but part of the outgoing radiation from the surface is retained by GHGs including water vapor That lowers the ratio between TOA solar radiation and what reaches the surface as solar SW LW greenhouse LW This is far better explained by Dr Scafetta in this RC discussion And please reread the solar cloud connection of fig 1 of Kristjansson where over a solar cycle 0 5 W m2 TOA the observed change in low cloud cover is within 2 I have no figures yet what this means in radiation budget expect some answers in a few weeks But a change of 1 7 in high level clouds over 1 decade caused a change of 1 2 W m2 in reflected SW and 3 W m2 more IR radiation to space over the 30N S band Or a pretty significant change in radiation budget 86 Ian Wilson says 1 Sep 2006 at 8 44 PM Has anyone considered the possibility that the Earth s heat balance is externally driven by a phenomenon related to solar activity Most climatologists limit the solar interaction with climate models to changes in solar insolation This is understandable since it is the only form of interaction that is easy to understand and quantify However it may be possible that slight changes in solar input eg UV radiation levels in the stratosphere or cosmic ray influences on low level cloud formation may be amplified by natural resonance matching to the overall climate system This may lead to long term heating and warming cycles in the oceans that are the result of upwheling of cool water from deep within the oceans Indeed historical data shows that about every 30 60 years the Nothern Pacific ocean undergoes sustained periods of cooling which by their scale and magnitude must influnece the overall heat balance of the planet Though it still considered very controversial evidence is emerging that regime changes in the Pacific ocean the last of which was in 1977 may be caused by small variations in the rotation rate of the Earth that are forced by changes in the level of solar activity Response The answer to your first question is yes of course The conclusions from those studies do not support the idea that solar activity which has been roughly stable since the 1950s has anything to do with the ongoing rise in temperatures We are among those climatologists who have explored the intereactions of UV forcing as a mechanism to enhance the solar impact and that is a valid idea we have some new results which I m sure you ll find interesting under review at the moment However the lack of solar activity trend in recent decades makes it very difficult for any solar mechanism even unknown ones to account for the recent climate changes As to your last point the idea that Pacific climate is affected by tiny changes in the Earth s rotation is ridiculous and not controversial at all The causality is the other way around if there is any connection at all gavin 87 Barton Paul Levenson says 2 Sep 2006 at 8 51 AM Re 85 well then please provide a quantitative estimate that refutes my estimate and explain why it does so Show your work 88 daCascadian says 4 Sep 2006 at 9 43 PM Ian Wilson Has anyone considered the possibility that the Earth s

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    7 29 AM Re Gavin s response to 86 Solar activity does have to have increased since 1940 to explain a significant part of the recent warming All that is needed is unrealized climate commitment from continuation of the high levels of solar forcing reached by 1940 A constant forcing applied to a pot of water can still result in an increase in the temperature of the water The realization of the temperature increase from the high level of solar activity was delayed interrupted by a period of aerosol cooling and there was also a significant but not necessarily large contribution from the increase in GHG forcing and perhaps a contribution from internal climate variation as well Current models are not good enough to dismiss one of the highest levels of solar activity in 8000 years as a mere coincidence or to apportion attribution Response Think about it as a simple heating function with a large heat capacity If you increase the heating and then keep it steady you expect a delay in the response but than an asympotoic trend to the new warmer state Responses get smaller as time goes on Now in the real world the temperature response is increasing through time this is inconsistent with solar being the dominant driving gavin 103 Martin Lewitt says 15 Sep 2006 at 10 07 AM Re Gavin s response to 102 I agree it would be asymptotic to the new warming state if it were a simple heating function however if that was the case for the climate we wouldn t need the models The climate commitment studies show that temperature increases are significant for the first century and equilibrium sea level rise can take a millenium We know that an aerosol cooling period interrupted the warming trend The same feedback mechanisms that are proposed to enhance the CO2 warming are also applicable to solar forcing including warming induced increases in methane release Non linear positive feedbacks from reductions in ice and snow cover can also be operative If we had better sea level rise data for the whole period we might see that the heat storage curve into the ocean had a shape that better matched the simple function approximation than the land surface data does or we might have better information on internal climate modes that confused or delayed the temperature response If climate senstivity to CO2 is eventually shown rather than just assumed to be close to the sensitivity to solar I think a case can then be made that the GHG attribution should be equal or higher than the solar attribution despite the large uncertainty in our knowledge of the increase in solar forcing I am hopeful that breakthroughs in the physical realism of the models such as incorporating a parameterized version of the skin effect will allow us to get confidence in this climate sensitivity to CO2 even if we still don t have the data needed to validate the models to the accuracy needed

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    we are rightnow at the tipping point 63 Yartrebo says 9 Sep 2006 at 11 21 AM Re 52 Don t take a banner year for the fossil fuel industry and extrapolate out into the future Also don t rely on only one source for your information especially a biased industry source Claiming that oil production is growing at a 5 rate and coal at 7 5 is a very far out claim It might be so but it s such a high number that it needs to be backed up with some serious data and reasons to explain why in a world economy growing at a few percent a year energy usage is growing by around 5 a year coal and natural gas are about 20 25 of the world energy supply each and oil is about 40 which works out to a 5 weighted average using your numbers Increases in fossil fuel usage almost always lag behind GDP growth because of systematic underreporting of inflation and worldwide GDP growth is usually a few percent a year including every year from 2000 to 2006 China might be racing ahead and chalking up 5 10 emissions increases and 10 GDP growth but Europe has close to 0 emissions growth For a worldwide average 2 growth in energy usage is considered fairly rapid If energy usage was indeed growing at 7 5 long term with that kind of growth rate coal would approach 100 of the energy supply in a few decades then we would have to worry about a lot more than global warming things such as oxygen depletion only 20 or so of oxygen available and carbon dioxide poisoning over 5 is quite fatal would become major issues as 2100 came along as coal usage would increase about 1 000 fold doubling once every 10 years CO2 levels would be around 1 5 and growing by about 0 2 a year Obviously 7 5 is a ludicrous rate for long term fossil fuel usage The rest of your argument is quite sound but the energy numbers and extrapolation you posted are just really out of whack Please check your numbers with various sources including some non industry and non government sources those two tend to be perennial optimists I ve done so and you can find all sorts of contradicting information after all it s economics and politics two fields full of manipulation and lying Often even basic definitions ie what is oil are different from source to source leading to very different numbers 64 L David Cooke says 9 Sep 2006 at 1 05 PM RE 57 Hey Ray I have seen a clear indication in the Sept 2005 Duke study alluding to the capacitive coupling of heat content increase to the worlds warming However I have also observed that Sol s output indicates an inductive character If the cycles of source and the heating were in phase then as Sol was at maximum then the earth s content would be at minimum When Sol was at minimum then the earth s content could be at maximum To put the current GW character into your engineering perspective then if the phase has shifted such that the peaks matched could be a partial explanation for GW How would this phase be changed would be the question to address Has the sun s energy cycle shifted or has the Earth s heat cycle shifted Based on all the data here it appears that the Earth s heat content has not discharged sufficiently through the atmosphere into space As in a LCR circuit with a wave length of 11 or 22 or 41 odd years Given this it would appear that the additional Solar energy is going into increasing the ambient earth heat content However if the discharge path is simply at a higher resistance and not an open circuit then simply put the heat content will increase until either the capacitor or the resistor fails However unlike normal engineering rather then the resistor failing open in this case it should fail short circuited So what happens if the capacitor fails it would be likely the heat content out is going to match the heat content in Does this characteristic match any historical data Unless the worlds oceans are a good conductor I would suggest this is unlikely It would be more likely for evidence to the opposite that the capacitor fails open rather then the normally expected short circuit If the character of a failed capacitor is not observable then it must be the resistor that fails Meaning that at some point the energy content rises to the point the resistor shorts out and the heat content is dropped suddenly This characeristic would be very similar to what was observed in the 2005 hurricane season in the N Atlantic a sudden release of heat to the upper atmosphere where it can be transported to the Poles for emission into space Now if we simply had the means to observe a IR plume at the poles this effect should have been clearly observable Apparently the ENSO and the PDO are likely natural phenomena that seems to be a sign that this discharge event has occurred As of yet I have seen no other hypothesis that would explain these atmospheric characteristics If you have a better explanation of how these events occur I would be very interested in reading them Granted even my explanation is not a great model either however defining the devices and the circuit accurately can be important if you want to accuratly explain long term weather or small term climate outlooks from a model My concern when reading your post appeared to be the character you had alluded too did not match my understanding Have you a better definition of how you see the components and the circuit schematic Dave Cooke 65 John L McCormick says 9 Sep 2006 at 2 53 PM RE 63 Yartrebo lets give it a rest huh If you cannot trust BP to use figures that did not come from a org web page then we have nothing to discuss 66 KC Truby says 9 Sep 2006 at 3 45 PM So we have conflicting reports in the SAME YEAR Ocean Cooling Confounds Climate Models Climate Science August 14 2006 A new study of ocean temperatures indicates significant cooling over the years 2003 2005 This unexpected result has implications for climate models As Roger Pielke SR of Colorado State University says The explanation of this temporal change in the radiative imbalance of the Earthâ s climate system is a challenge to the climate science community It does indicate that we know less about natural and human climate forcings and feedbacks than concluded in the IPCC Reports Read more analysis from Professor Pielke here The Competitive Enterprise 67 Phil B says 9 Sep 2006 at 3 49 PM Peter Minnett I enjoyed your writeup I have a question Using the basic conduction equation from my physics book and length of L 05 m thermal conductivity of k 585 W m K and a delta T of 25 K I get 3 W m 2 If I look on your chart for night time conditions you have about 88 W m 2 A substantial difference What am I missing here Thanks Phil 68 Yartrebo says 9 Sep 2006 at 5 58 PM John why do you have such faith in the BP numbers They have the scientific rigor of a press release That rate of growth 7 5 for coal 5 for oil gives a 2100 projection that s more than 100 fold over the IPCC business as usual projection of CO2 emissions When much simpler possible explanations exist such as tar sand production being reclassified as oil production without backdating a common error in the energy industry and the admission of China that coal production was severely understated again without backdating why go with the explanation that stretches believability that we ve entered a brave new world where energy usage races ahead and breaks all historical ties to GDP growth I m not saying those are the reasons but they are two very large events that have happened in the last two years and could completely throw off to the upside any statistics that aren t properly backdated I cannot prove or disprove any of these allegations because BP keeps secret how it comes up with its numbers but the onus should be on BP to prove that their numbers are accurate and they have failed to do that PS Backdating means that if you change the definition of something like now including bitumen as oil production you revise the old data so that bitumen is also included in the old data It s so obvious that it s generally taken for granted in science but in the energy industry it s often not done probably for political purposes since the revisions are almost always up and not down 69 Robin Johnson says 9 Sep 2006 at 11 40 PM Uh Yartrebo and John John I don t think that you should extrapolate from two years data Plus fossil fuel production is not the same as fossil fuel consumption Coal and oil are often stockpiled oil and coal stocks often exceed many months of supply and with Middle East tensions and expectations of increased prices stockpiling would not be surprising Additionally there are plenty of good historical data sources available Try some searches over at The US Department of Energy The International Energy Review 2004 provides spreadsheet data that s quite interesting for stat heads Additionally according to The EIA 2005 over 2004 was only a 1 increase the 2004 4 increase over 2003 was slightly anomalous it would appear 1997 over 1996 showed a similar anomaly of 3 Yartrebo On the other hand the acceleration of energy consumption by India China Middle East and South America from increasing population and increasing consumer Western style consumption WILL drive energy usage up India and China instead of leapfrogging into modern technologies are adopting inefficient but quick and cheap energy technologies Oops So I fully expect energy usage to balloon beyond the usual 1 2 increase with the recent population bulges in Southwest Asia Africa and Latin America along with increased Westernization As the oil runs low coal gasification will become economical double the CO2 increase per barrel so things will definitely get worse from a CO2 perspective So to say that that fossil fuel consumption growth is going to stay at 1 2 per annum may not be true Even 2 growth is ruinous twenty years of 2 growth translates into a 50 increase Cue the doom music 70 Robin Johnson says 9 Sep 2006 at 11 44 PM And I should have added according to the IEA world coal usage grew 8 in 2003 and 7 in 2004 World natural gas usage grew 4 per year in 2002 2003 and 2004 71 John L McCormick says 10 Sep 2006 at 10 58 AM RE 68 69 70 Folks are we dancing on pinheads again The fact I included one year growth percentages of oil coal gas production consumption what does that really matter the fuel will be consumed has absolutely nothing to do with my original response to Mr Turner s post at the thread titled How do we know that recent CO2 increases are due to human activities 22 DEC 2004 PLEASE read his post on the other thread then my post at 48 here and try to see the salient point I was offering Mr Turner to consider There I said increased fossil fuel production and of course fossil fuels are produced for consumption even if they are stockpiled for a rainy day emitted more CO2 than sinks can accommodate so the atmospheric CO2 concentration increased Because of global warming To the degree that warmer oceans and land presented positive feedbacks of CO2 YES I say be done with the discussion about Yartrebos interpreting my 2003 2005 growth percentage as a projection of future fossil fuel production I DID NOT MAKE PROJECTIONS Enough PLEASE 72 Graham Dungworth says 10 Sep 2006 at 11 40 AM There is an alternative way to check the growth of emissions Firstly look at a global polltion map from envisat that dates back to 2002 I ve asked them to update it a year ago to no vail yet GLOBAL POLLUTION Secondly the most up to date figure plots of the famous Keeling curve which shows the build up of CO2 in the atmosphere are available from NOAA They were not available for a year prior to this January passed a consequence of grant funding cancellation by the US administration Many complained bitterly inc myself so they were reintroduced KEELING CURVE The CO2 graph opens for Mauna Loa in the central Pacific Click for other locations The saw tooth is a consequence of photosynthesis in the Northern Hemisphere starts in Spring and plants absorb CO2 so the amount of CO2 drops At the end of the growing season plant life decays releasing excess CO2 into the atmosphere and the build up of CO2 occurs through to the following spring Keeling noted that most productivity which is land based occurs in the Northern Hemisphere and dominates that for the southern hemisphere If you toggle for isotope 13CO2 data another fascinating factor is explained as such Firstly From the pollution map it is evident that most fossil fuel combustion occurs in the Northern Hemisphere If you toggle around for many other global stations it becomes evident that it takes between 6 months to 1 year for CO2 released to diffuse around the atmosphere Secondly a bit of detailed chemistry is relevant Carbon is recycled geochemically by CO2 emissions from volcanoes oceanic ridges wethering of limestiones and calcareous shales etc Biosynthesis by life namely photosynthesis preferentially selects the common isotope 12C 99 abundant because the heavier stable isotope 13C 1 abundant is kinetically slower it doesn t diffuse into leaf tissue or calls as quickly The carbon in fossil fuels such as coal oil is isotopically light ie it is depleted in the heavier 13C isotope By definition limestone CaCO3 is taken to have zero depletion ie 0 on a parts per thousand mil scale Coal oil etc when analysed give values of ca 30 per mil ie the negative sign means they are depleted in the heavier isotope by 30 patrs per thousand relative to the defind 0 depletion or enrichment for limestone Some biogenic gases eg methane are often even more depleted down to 50 per mil When you look at the C isotope fractionation for CO2 in the atmosphere it is vastly different It used to be ca 7 per mil in agreement with volcanic emissions igneous carbon and even diamonds Currently the value is below 8 per mil The most depleted value is in Korea I presume because of all the industrial emissions from China For Mona Loa you can see a variable trend where recently CO2 in the atmosphere is getting isotopically lighter by 0 06 per mil annually The CO2 isotope values can be used to do a mass balance on atmospheric fossil fuel emissions The mass of the atmosphere is 5 12 10exp21g If CO2 is 385 ppm by volume we can calculate the mass of CO2 knowing its atomic mass is 44 and that of the other components N2 and O2 etc average 30 so we have to multiply the volume mesure by 44 30 to get CO2 mass measure It is claimed by the IPCC that ca 5 7 gigatonne CO2 note carbon is atomic mass 12 to get gigatonne C we would multiply by 12 44 since CO2 is C plus 2 O oxygen atomic mass 16 is combusted annually THAT fossil fuel combustion has an isotope C of 30per mil It dilutes the heavier ca 8 characteristivc of the atmosphere as a whole From one year to the next the mass balance is Total Mass carbon yr1 fractionation factor1 Total Mass carbon yr2 fractionation factor2 X 30 where X gigatonne fossil CO2 generated from yr1 to yr2 Doing all of that from Mona Loa data that I think is the best database I got 5 78 Gigatonne CO2 from current fossil fuel released recently per annum Hence There is no justification for claiming that fossil fuel combustion rates are growing by that huge 7 8 On errors 30 I think is the value I think was used to corroborate former IPCC book values There are accumulations of Russian biogenic gas that fractionate down to 70 This would reduce the apparent isotope determination of combusted fossil fuel Nevertheless if we see a marked increase in that downslope isotope gradient we will be aware of it within a time frame of months Both the envisat polltion map if updated annually and the carbon isotope database will provide a valuable alternative method for checking on national and global emissions 73 Graham Dungworth says 10 Sep 2006 at 2 46 PM Re Apologies For GLOBAL POLLUTION http www esa int esaEO SEM340NKPZD index 0 html For KEELING CURVE http www cmdl noaa gov ccgg iadv index php 74 John L McCormick says 10 Sep 2006 at 3 27 PM Graham thank you A very interesting post But I believe the following is in need of adjustment You said It is claimed by the IPCC that ca 5 7 gigatonne CO2 note carbon is atomic mass 12 to get gigatonne C we would multiply by 12 44 since CO2 is C plus 2 O oxygen atomic mass 16 is combusted annually 5 7 gigatonne CO2 should read 5 7 gigatonne Carbon which multiplied by 44 12 or 3 667 would yield 20 9 gigatonnes of CO2 I see this reversal often C becomes CO2 and CO2 becomes C even among the pros Do you

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    write this is one of those cases where it is not what you don t know that hurts you but what you do know that is not so Yes 21 Gar Lipow says 5 Sep 2006 at 11 52 PM Re 20 yes 22 L David Cooke says 6 Sep 2006 at 8 19 AM Dr Schmidt Thanks I was able to locate this link regarding the surface following sensor http uop whoi edu technote 9611tn html Dave Cooke 23 Richard Allan says 6 Sep 2006 at 9 46 AM Will wind speed alter this relationship substantially For example supposing it is more windy when it is very cloudy A stronger wind would I imagine cause more evaporation and cooling of the skin layer making the skin minus bulk temperature difference even more negative Removing this effect from Figure 2 ie removing some of the hypothetical skin minus bulk temperature differences due to windy cloudy conditions would increase the calculated gradient further Of course if there is no relationship between wind speed and net radiation then this does not apply Presumably this has been checked or would be easy to investigate Response Anything that effects the surface fluxes latent sensible LW SW will effect the skin temperature difference and so wind speed clearly will There is a general relationship between the diurnal cycle and winds though I m not sure of the amplitude of that at this particular site But the amount of data looked at here is averaged over a number of days and so variations in incoming SW and in wind speed are probably well enough sampled to give a robust result Peter Minnett is currently on a cruise off Iceland but when he gets back I m sure he d be happy to give you more details on the other factors in this physics gavin 24 Hank Roberts says 6 Sep 2006 at 10 10 AM The excerpt I quoted says below windspeed that disrupts the skin layer heat transfer occurs by molecular processes my guess would be that includes include both radiation and evaporation anyone know I d also think humidity at low windspeed would be pretty close to saturated in the air right next to the skin layer limiting evaporation rate and that wouldn t change as quickly when cloud cover changed compared to radiation rates 25 Jeffrey Davis says 6 Sep 2006 at 10 44 AM I m thoroughly confused We ve just had a recent post that said that there had been an unexpected drop in ocean temps Or at least that a new batch of instruments had indicated a drop Response short term drop long term heating gavin 26 L David Cooke says 6 Sep 2006 at 11 55 AM RE 25 Dr Schmidt If all things remained the same then what accounts for the unexpected drop in ocean temps It appears the SST radiational and convective processes have not changed The ocean currents have been relatively stable with a 20 Deg E and about a 15 Deg N deviation in the N Atlantic seasonal Anti Cyclonic position This is not unique over the last 30 years If anything the CO2 in atmospheric solution has increased the data from ARM gov indicates the solar SW LW input appears stable with a slight SW decrease There has been a change in the apparent average humidity and air pressure according to the NESDIS NCEP data for the NH Analysis indicating a greater deviation of the Northern Jet Stream and an apparent increased rate of pressure zone movements across the temperate zones I know this is a weather phenomenona and not climate however it would seem unusual that a possible natual deviation might be great enough to overcome an apparent 30 year trend suddenly without a noted significant weather event other then a possible SST heat transport of the 2005 Hurricane Season Can you offer any insights as to the apparent deviation BTW I have not noticed it in any of the historic data but have you seen the New Foundland SST deviations as great as occured earlier this summer Is it possible that the heat transport of the 2005 hurricanes may explain this years deviation If this is true is it possible that the GHG as a contribution to GW may not be as big an issue as has been presented in the popular press Thanks for you consideration I apologize if it may be more appropriate to take this offline Dave Cooke 27 Carey Scortichini says 6 Sep 2006 at 1 52 PM Regarding Figure 2 Have the data in this Figure been published in a peer reviewed journal What is the correlation coefficient associated with the linear fit of the data Response This is unpublished data but I know that it is being written up as part of a larger discussion on ocean air sea interaction As mentioned above Peter is on a cruise right now but I m sure he will be happy to answer your questions when he returns gavin 28 J A Smith says 6 Sep 2006 at 3 03 PM As an oceanographer working on air sea interaction and mixed layer dynamics I hope I can clarify this issue somewhat in fact I m at sea right now on the R P FLIP gathering data to study wave and mixed layer dynamics but this is off the point I think a major aspect of the balance has been glossed over the ocean is heated mainly by the visible part of the spectrum the energetic part of the sun s glare This penetrates several meters blue green can penetrate several 10 s of meters particularly in the clear water found away from coasts In contrast the only paths for heat LOSS from the ocean are infrared blackbody radiation and latent heat evaporation The sun heats the uppermost few meters this has to find its way to the actual very thin surface layer to be lost In equilibrium then there is a significan flux toward the surface a few cm under and the sense of flux from infrared alone has to be significantly upward Given this it is quite clear that any reduction in the efficiency of upward radiation by say reflecting it right back down again will have to be compensated for by increasing the air sea skin temperature difference hence having a warmer subsurface temperature This still leaves aside the latent heat flux which in general accounts for something like half the upward heat flux The balance is NOT as portrayed here between up and down infrared rather it is downward visible including ultraviolet even versus upward NET infrared and latent heat fluxes Once trapped in the mixed layer any excess heat makes its way down into the interior via much larger scale processes including lateral advection and mixed layer deepening due to wind and wave induced motions This large scale vertical redistribution takes a while decades to hundreds of years before equilibrium is re established The fact that we can already see this is quite remarkable 29 Hank Roberts says 6 Sep 2006 at 4 36 PM The fact that we can already see this is quite remarkable Say more please For us non experts remarkable how Change in rate compared to prior experience 30 Joseph O Sullivan says 6 Sep 2006 at 6 08 PM Thanks you JA Smith Just the fact you are commenting from the R P FLIP is really interesting I remember reading about FLIP when I was young and trying to pick a career Info about the FLIP is here http www mpl ucsd edu resources flip intro html The explaination about different wavelengths is very helpful It s useful to step back and see the big picture when you are trying to make out the details I understand the orginal post better now I try will apply what I have learned about climate science and try to answer 29 Hank Roberts The large scale vertical redistribution of the excess anthropogenic heat is remarkable because of how rapidly it is occuring and how widespread it is If I remember correctly the signal of the excess heat detectable in the oceans is not just a local phenomenon Because it was so widespread natural cycles were ruled out Second the oceans as a whole and not including current shifts like ElNino change temperature slowly The heat signal was detectable quickly and is increasing quickly and this is unusual in the normally stable oceans 31 Hank Roberts says 6 Sep 2006 at 8 01 PM Info about the FLIP is here http www mpl ucsd edu resources flip intro html Yeah I remember when that was first launched and tested Wonderful ship amazing idea 32 Peter Hearnden says 7 Sep 2006 at 4 57 AM If the oceans aren t warmed by LW radiation then how come they are not significantly cooler than we see closer to the 18C of a non ghg world 33 herb says 7 Sep 2006 at 6 20 AM LOVE YOUR BLOG PS i am creating a website called weather on the web where everyday people take pictures and write blog posts about weather in their area and around the country this is not spam or anything i am a total weather fanatic if interested please email me herb1090 at comcast net again email not comment thanks 34 Hank Roberts says 7 Sep 2006 at 10 15 AM Peter nobody said that See 28 35 Peter Hearnden says 7 Sep 2006 at 11 13 AM Re 34 Hank yes of course I m not saying that what happens I m saying it seems to me that s taken to an extreme the implication of what Fred Singer is saying Clear the world oceans do respond as the main post and 28 say 36 Bryan Sralla says 7 Sep 2006 at 12 40 PM Re 28 J A Smith s commentary was on the mark This RC post confuses the whole issue of ocean heat balance As a starting point the only significant external heat source is incoming shortwave This incoming shortwave heating is balanced by ocean heat loss through back radiation 41 evaporative heat loss 53 and heat loss by conduction and convection 6 The net changes in heat loss through these processes are affected by GHG s For example increased well mixed CO2 and water vapor decrease the rate of heat loss through back radiation It is humbly suggested that the processes governing ocean heat changes are not as straitforward as they might seem however Ocean heat content is ultimately controlled by a number of complicating factors including positive and negative forcings and feedbacks dealing with clouds water vapor and also CO2 These forcings and feedbacks effect the processes by which the ocean looses heat to remain in balance It would be my suggestion that all the governing factors are still incompletely understood Since the heat storage capacity of the ocean is 1000 times that of the atmosphere having a solid handle on all these is crucial to accurately projecting even average mean climate across multi decadal time The new ocean heat numbers are not mearly interannual variability but represent a challenge for the community to better understand all of these processes Response Actually downward LW 350 W m2 is about twice as large as absorbed SW 175 W m2 as a heat input into the ocean gavin 37 Rob Neff says 7 Sep 2006 at 2 40 PM I was wondering if you were familiar with Lyman s latest report http www pmel noaa gov lyman Pdf heat 2006 pdf My understanding of it is is basically that every so often the equatorial oceans get hot enough they blow away the clouds and release heat into space This accounts for the tropics not experiencing big temperature shifts during times of global warming But doesn t let Europe and North America off the hook unfortunately since we re not so close to the equator I was wondering did I get this simplification right and how this would affect climate modeling Response See our recent post gavin 38 Bryan Sralla says 7 Sep 2006 at 3 33 PM Re 36 This incoming shortwave is balanced by net ocean heat loss through back radiation 41 The key word net should have been used Obviously much of the LW emmitted is absorbed in the atmosphere and emmitted to the ocean Gavin thank you For the layman however this may be unclear as is this thread In its simplest form averaged over a year can not the ocean heat balance be expressed as Q s Q b Q e Q h where Q is the change of energy expressed in Joules Q s is incoming shortwave Q b is the net back radiation loss Q e is the net loss from evaporation and Q h is the heat loss by conduction and convection Please forgive a math challenged geologist 39 Graham Dungworth says 7 Sep 2006 at 4 49 PM Re 28 onwards There s more than just the physics of absorption emission Up to 9 of the incoming short wave radiation 400 700nm is incorporated into biomass by photosynthesis admittedly requiring other nutrients in optimal abundance One third of this is lost by respiration with degradation back to CO2 eg at night The biomass creates degraded longer wave energy at depth well below the skin depth The net effect of biomass is to enhance warming The residue of biomass is incorporated into sediments eventually as fossil carbon limestone sulphides and sulphates 40 Yartrebo says 8 Sep 2006 at 10 01 AM Photosynthesis is a pretty small contribution as the necessary nutrients are almost never all available particularly in the open ocean I would be suprised if so much as 1 of incoming SW radiation was incorporated into biomass 1 is about as efficient as the most efficient land crops are at photosynthesis net of respiration Also virtually all of the biomass rots degrades to CO2 or CH4 long before it has a chance to settle into sediments This is a good thing or else the biosphere would have run out of carbon long ago as plate tectonics only recycles buried carbon on the scale of tens to hundreds of millions of years 41 L David Cooke says 8 Sep 2006 at 11 02 AM Re 39 Hey Graham Of the remaining SW 160 Watts meter 2 what percentage results in the death of biomass and the removal of the associated carbon fixing activities Is there an approximation as to the percentage of annual phytoplanton that has been killed by UV since 1970 as a result of the Stratospheric Ozone reduction By the way how would this be measured sampled turbidity and at what depth would this measure be appropriate Or maybe a correlation of Dobson Units to metric tons of global biomass reduction per day due to the UV ionizing effect We also have the question of if the phytoplankton is not killed but just mamed a little by UV would this have a negative effect on the carbon fixing level of activity The next question is what is the ratio of UV affected biomass CO2 fixation to CO2 fixation of non UV affected biomass Sorry if the questions appear retorical I actually am interested if work in this area has been done I have seen little as of yet As to the LW effects I am curious if the phytoplankton are dead and they add to the turbidity then they would particpate in an increase in the conversion of incoming EMR to LW and it s transfer to the liquid it is suspended in would they not Would turbidity not also play in the potential heat content of the top 10 40 meters Is it possible to extract the turbidity data from the OceanColor data Sorry for the many questions I just have not seen any data that addresses them Since my thoughts would not be unique I can only assume that this data is not of any value in relation to the issues Dave Cooke 42 Michel says 8 Sep 2006 at 12 04 PM Just juming on this thread to signal that The Economist weekly is doing a special on climate change the editorial is free I think http www economist com opinion displaystory cfm story id 7884738 43 savegaia de says 8 Sep 2006 at 12 16 PM Hello just want to share this new wiki on AGW http globalwarming wikidot com Pretty new and i looking forward to relevant contributens wikis additions ideas comments and such Cheers 44 Graham Dungworth says 8 Sep 2006 at 3 18 PM Re 40 and 41 The ideal conditions I quoted are perhaps never realised so I concur with Yartrebo that much lower efficiencies are probable Of course if oceanic biomass or nutrient levels have not changed over time the system remains in equilibrium there is no net change However over the time frame cited for GW effects we have degraded landscapes forest clearance and soil erosion carries an increased load of nutrients into the oceans Increased algal and plankton blooms in the Mediterranean and European coastlines are now annual events Biomass carbon oxidises back to CO2 releasing the same heat of combustion that generated it utilising SW radiation That gives rise to the upward kick in the Keeling curve saw teeth during the Northern winters Most of the photosynthesis and respiration apparently occurs in the northern hemisphere Again only a tiny fraction of carbon and sulphur are preserved in the crust and as Yartrebo points out cycling occurs over a very long timescale ca t1 2 300 400 million years Igneous and volcanic rocks have very low carbon and sulphur contents and reduced iron FeII the exhaled gases are oxidised CO2 and SO2 However carbon in sediments is predominantly carbonate 1 carbon reduced atom to 5 Carbonate carbon atoms sulphate

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  • Carl Wunsch, The Economist and the Gulf Stream « RealClimate
    as the idea of a shutdown of the THC is dependent on the continuous loop or conveyor analogy of the ocean circulation this hypothesis is not tenable With respect to the 8 2 Kyr event I believe this was Broecker s theory in the nineties I understand he has recently stepped back from the hypothesis that the event was caused by a freshwater hosing event I may be wrong on this though There have been plenty of recent papers e g Curry Mauritzen 2005 which have analysed the North Atlantic in detail and have found to date no observable change in the ocean circulation In January this year a Norwegian report on the NwAC over the past 10 years showed a warming but slowing surface current a change but no net flux in heat transport over the period I am not saying the Wunsch is correct in everything that he says but I do think that collectively we may sometimes take depictions like the THC for granted and that we shouldn t Therefore I praise the good professor for drawing our attention to this Regards 14 Hank Roberts says 3 Oct 2006 at 6 35 PM Visualize Lovelock smiling at this feedback mechanism krill elevated the turbulence by 3 to 4 orders of magnitude and increased mixing between water layers by a factor of 100 From http www newscientist com article dn10135 turbulent times means krill help climate html excerpt Eric Kunze and John Dower at the School of Earth and Ocean Sciences at the University of Victoria in British Columbia Canada and colleagues have measured the turbulence generated at dusk by krill as they rise to the surface of the ocean to feed During the day krill hide about 100 metres below the surface As night falls they ascend in vast numbers In the Saanich Inlet for example krill occur in concentrations of up to 10 000 per cubic metre a microstructure profiler measures shear forces temperature and conductivity on a microscale allowing the scientists to determine the amount of turbulence Shear sensors are like old phonograph needles that are very sensitive to bending the layer of krill came up and we immediately saw that the turbulence levels were higher And they were much higher the krill elevated the turbulence by 3 to 4 orders of magnitude and increased mixing between water layers by a factor of 100 One of the reasons we care about mixing is that surface layers mix with atmospheric gases says Dower This could play a role in the drawing down of carbon dioxide from the atmosphere into the ocean end excerpt 15 Jeff Weffer says 3 Oct 2006 at 10 32 PM Thought everyone could benefit from seeing an animation of the Gulf Stream over a 1 year period Each frame is 7 days Takes awhile to load but worth it http www psc edu science OKeefe OKeefe movie mpg 16 Chuck Booth says 3 Oct 2006 at 11 19 PM Re 4 Or is evaporation increasing the saline concentration making the hot water denser and thus countering the effect No between 0 and 10 degrees N latitude the equatorial rains reduce the salinity making the surface waters less dense Salinity is elevated due to excess Evap Precip E P at around 15 35 degrees N latitude and 0 30 degrees S latitude 17 William Astley says 3 Oct 2006 at 11 34 PM http oceans pmel noaa gov Pdf heat 2006 pdf search 22Recent 20Cooling 20of 20the 20Upper 20Ocean 22 The above paper provides evidence for massive cooling of the earth s ocean 2003 to 2005 I would assume due to changes in the earth s upper atmosphere Recent 2003 to 2005 Cooling 3 2 x 10 22 J of the Upper Ocean Published 20 September 2006 Geophysical Research Letters We observe a net loss of 3 2 1 1 x 10 22 J of heat from the upper ocean between 2003 and 2005 Using a broad array of in situ ocean measurements We have detected a new cooling event that began in 2003 and is comparable to the one in the early 1980 s 6 x 10 22J lost from 1980 to 1983 Assuming the 3 2 10 22J was not lost to the deep ocean believed not to be possible in the short time interval previous work suggests that the scale of the heat loss is too large to be stored in any single component of the Earth s climate system Levitus et al 2005 A likely source of the cooling is a small net imbalance in the 340 W m 2 of radiation that the earth exchanges with space Imbalances in the radiation budget of the order of 1 W m 2 have been shown to occur on these time scales Wong et al 2006 The observed rapid periodic 200yr 500yr 1500yr drops in the climatic record 5C to 20C drop in temperature on the Greenland Ice Sheet Also observed in the Southern Hemisphere but response is less due to land mass distribution and cryosphere differences between the two hemispheres were and are still believed by some to be due to changes in the thermohaline conveyor Seager et al disproved that hypothesis and notes in his paper that his quantitative conclusion that a complete stoppage of the thermohaline conveyor only result in a 1C to 2C cooling of Europe is supported by publish work of others and simple fundamental climatic facts and analysis The following is a link to Seager s paper http www atmos washington edu rennert etc courses pcc587 ref Seager etal Gulfstream qjrms02 pdf search 22Seager 20et 20al 20 2B 20Gulf 20Stream 22 Response We discussed the Lyman et al paper in an earlier thread and I note that your reading of Seager s paper is complelety erroneous gavin 18 wayne davidson says 3 Oct 2006 at 11 47 PM Excellent article professor Wunsch brings out what I have learned by watching daily Global Weather animation maps there are particular locations on Earth which seem by illusion to give birth to Cyclones one of my favorite spot s is next to Southeast Greenland where massive lows are often generating steep pressure gradients always with very significant winds sea surface circulation is of course counterclockwise A Question always comes when watching this Which current gives rise to which water or air current Since at that location there are huge streams with significant temperature differences equally clashing in both mediums a conclusion would be that both air and water are spinning under the same influences If so it is a better concept in understanding water and air circulations 19 Trevor Maynard says 4 Oct 2006 at 4 23 AM Excellent post This idea about driving does a car analogy work here I think I drive my car But actually in an energetic sense it is the engine that does that However my steering of the car modulating is far more important to everyone s safety In a plain English sense I do drive the car and the density patterns do drive the THC Perhaps steer rather than drive would be a better word 20 Stefan says 4 Oct 2006 at 7 56 AM The term thermohaline circulation has been criticised as Gavin states because it tends to perpetuate the idea that it is the temperature and salinity fluxes that drive the circulation On that basis we d also need to abandon the term steam engine as this machine is not driven in an energetic sense by steam but by coal or wood The term thermohaline circulation THC on the other hand is a time honoured and well established term in physical oceanography since early in the 20th Century which was coined and used by pioneers of our field like J Sandström and A Defant who clearly knew that the temperature and salinity fluxes do not provide the energy for this type of flow They were the people who discovered and analysed this in the first place I would caution against throwing out our scientific heritage for no good reason and with no better term to replace it The term thermohaline circulation refers to a particular driving mechanism which is clearly distinct from the way tides or the directly wind driven circulation are driven and in which thermohaline surface fluxes play the distinctive and crucial role even if they do not provide the energy Note also that this energy argument applies only to a special case the long term multi millennia equilibrium circulation in a closed system i e the global ocean It does not apply to the transient case i e a polynya opening up in ice can drive a thermohaline flow even in an energetic sense see Buffoni et al 2002 It does not apply to the regional case e g the thermohaline circulation between Atlantic and Mediterranean driven by the fact that the Mediterranean loses about a meter of water each year due to evaporation The term MOC has a very different meaning To paraphrase my recent review paper Although the terms THC and MOC are often inaccurately used as if synonymous there strictly is no one to one relation between the two The MOC includes clearly wind driven parts namely the Ekman cells On the other hand the THC is of course not confined to the meridional direction rather it is also associated with zonal overturning cells Unfortunately some people have recently started to use the term MOC when they really mean the THC perhaps they feel there is something wrong with using THC without fully understanding the issue Rather than abandon the term THC and with it a useful concept and a part of our scientific heritage my plea would be to be more accurate in using the term After all if the great oceanographers of the 20th Century had not invented and used this term to distinguish flows by driving mechanism we would probably need to invent it now Buffoni G A Cappelletti and P Picco 2002 An investigation of thermohaline circulation in Terra Nova Bay polynya Antarctic Science 14 83 92 21 yartrebo says 4 Oct 2006 at 3 44 PM Re 10 Increasing the pressure of water 4C has extremely little effect on the temperature because cool liquids are almost incompressible for any pressures found on Earth I m guessing that geothermal heating is pretty minor too as the heat flux is only about 20mW m 2 and the deep ocean is pretty close to 4C everywhere If I understand correctly things happening near the surface are what drive the deep ocean currents 22 William Astley says 4 Oct 2006 at 7 28 PM Re 17 This in follow up to my comment concerning Seager s article in the July August 2006 issue of American Scientist which is based on the paper Seager et al 2002 Is the Gulf Stream responsible for Europe s Warm winters Seager article s in American Scientist challenges the hypothesis that a stoppage of the thermohaline conveyor can cause dramatic drops in the North Atlantic temperature such as the Younger Dryas The Younger Dryas occurred 12 900 years ago and was a dramatic interruption of the Holocene interglacial warming which brought near glacial cold back to the Northern Hemisphere Seager For many years the leading theory for what caused the Younger Dryas was a release of water from glacial Lake Agassiz which flooded into the North Atlantic it was said lowering the salinity and density of surface waters enough to prevent them from sinking thus switching off the conveyor The North Atlantic Drift then ceased flowing north and consequently the northward transportation of heat in the ocean diminished The North Atlantic region was then plunged back into near glacial conditions Or so the prevailing reasoning went Recently however evidence has emerged that the Younger Dryas began long before the breach that allowed flood water What is more the temperature changes induced by a shutdown in the conveyor are too small to explain what went on in the Younger Dryas Some climatologists appeal to a large expansion in sea ice to explain the sever winter cooling I agree that something of this sort probably happened but it s not at all clear to me how stopping the Atlantic conveyor could cause to bring on this vast change But from what specialists have long known I would expect that any slowdown in the thermohaline circulation would have a noticeable but not catastrophic effect on climate The temperature difference between Europe and Labrador would remain Temperatures will not even drop to ice age levels not even to the levels of the Little Ice Age All Battisti and I did was put these pieces of evidence together and add a few more illustrative numerical experiments Why had these collective studies not already led to the demise of claims in the media and scientific paper alike that the Gulf Stream keeps Europe s climate just this side of Glaciation It seems this particular myth has grown to such a massive size that it exerts a great deal of pull on the minds of otherwize discerning people Does Seager provide a fundamental challenge to the hypothesis that the Thermohaline circulation is the Achilles heel of our climate system http www americanscientist org template AssetDetail assetid 51963 fulltext true print yes Response Very nice cutting and pasting I would recommend reading the entire article though Seager takes exception to the notion that the difference between Labrador and Europe is due to the heat transported by the Gulf Stream Fair enough this has sometimes been claimed in popular articles on the subject and is wrong The same is true for the new ice age idea should the circulation cease Neither of those things are being claimed here However that is definitely not the same as saying that the ocean transports don t affect European climate it just indicates that they affect the North Atlantic relatively uniformly across longitude It s true that the trigger for the Younger Dryas remains a mystery but whatever the trigger the principle effect was almost certainly an almost complete shutdown in overturning look at some of the recent work by McManus and colleagues for support of that The slowdown in your next quote refers to something else entirely the projected changes in the overturning as a function of greenhouse gas forcing and I would actually go further it s highly unlikely that any such slowdown would give any actual cooling in Europe More likely it would simply locally moderate the global warming I don t see Seager s work as a fundamental challenge to anything other than over excitable reporters Like with Wunsch above it would be nice if people could debunk myths without sowing confusion that doesn t seem to be the case here gavin 23 Eric Swanson says 4 Oct 2006 at 10 03 PM Re 22 Seager s paper in the American Scientist refers back to earlier work presented in 2002 In that paper Seager et al compare the results of 2 modeling experiments The more recent experiment using the NCAR CCM3 is compared with earlier runs with the NASA GISS model presented in 1999 To understand the latest paper one must read the 2002 paper which begins by stating To test this we performed a pair of experiments with an atmospheric general circulation model GCM coupled to a uniform depth mixedlayer ocean In both experiments the sea ice cover was held  fixed at its annual mean value in order to eliminate feedbacks then further notes The GISS model also includes a thermodynamic sea ice model so the sea ice extent was allowed to adjust when the specified OHT was removed and later The remarkable exceptions are that in the GISS model where sea ice cover is allowed to vary removal of OHT causes an expansion of winter sea ice near Kamchatka and in the Norwegian and Barents Seas that in turn causes dramatic cooling as much as 20 degC of the air temperature immediately above and to the east The more fundamental difference is that in the GISS model expansion of sea ice when the OHT is removed causes the surface air north west and north of Scandinavia to cool by many degC more than in the CCM3 experiment Finally admitting that More problematic for certain regions is the treatment of sea ice In CCM3 we held the ice cover fixed but when it was allowed to vary in the GISS model removal of OHT caused a large expansion of seasonal ice cover in the Kamchatka region and in the Norwegian and Barents Seas cooling the air above and to the east The thermodynamic sea ice model in the GISS GCM probably overestimates the increase in sea ice extent But how can they be sure that the GISS over estimates the change in sea ice if they didn t model changes in sea ice with their other simulation And the dramatic cooling over Northern Europe might be just the beginning of changes as they only ran their experiments for 30 years Surely it is to be expected that changes in sea ice would be a major consequence of a shutdown of the THC and any attempt to model such a change must include a realistic dynamic sea ice model Seager s work did not perform such an experiment and downplayed the effects found in earlier work Why then would anyone accept this latest modeling result using the CCM3 Perhaps the experts can tell us why 24 Stephen Berg says 4 Oct 2006 at 11 18 PM This story warns of great warming in the Northeastern US http today reuters com misc PrinterFriendlyPopup aspx type topNews storyID 2006 10 04T205644Z 01 N03258792 RTRUKOC 0 US ENVIRONMENT WARMING xml 25 Steve Sadlov says 5 Oct 2006 at 3 22 PM RE 18 The Bermuda High is a massive and persistent feature Sargasso would not exist without it

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  • Revealed: Secrets of Abrupt Climate Shifts « RealClimate
    be nailed down more precisely than the clock stability My analysis based on the CLEANEST Fourier spectrum Foster 1995 Astron J 109 1889 indicates a period of 1461 4 yr However the error calculation is predicated on a null hypothesis which we know to be false under such circumstances a better estimate of the error range is the FWHM in a Fourier transform This gives an estimated period of 1461 27 yr So the underlying driving force has a very precisely determined period but it may exhibit random cycle to cycle fluctuations contributing to some of the irregularity in the timing of D O events in the GISP2 data BTW Stefan s analysis of sources of the irregularity in event timings was in my opinion very nicely done It reminds me of O C analysis as is regularly applied to variable stars in astronomy but Stefan treats the sources of variation correctly as is sadly too often not the case in astronomy my compliments 11 andrew worth says 9 Nov 2006 at 12 30 AM I wonder if GH forcing can be a substitute for solar forcing in initiating a DO event if it is caused by solar forcing 12 L David Cooke says 9 Nov 2006 at 12 33 AM RE 8 Eric s Comment Dr Steig I don t know that that I would feel comfortable saying there is no evidence of warming entering the area There does appear to be a warming in the NA at the Labrador Sea interface Looking at the Rossby Wave effect on the Jet Stream it appears to be affecting the Bermuda High whaich has moved from the normal 60 Deg W to around 30 Deg W which would be sufficient for an extension of warmer tropical waters moving towards this region and appears to be causing the higher temperature subtropical SSTs to pool in the this area Based on the 2005 data there had appeared to be a notherly wind reducing the ice pack in the Bering Straits and now we appear to have the opposite effect this Fall in both the Norwegian Sea and Labrador Sea areas When looking at the ice pack data this Fall the extension of the Arctic ice pack towards the Bering Strait seems greater and the icepack build up aroung the islands at the western edge of the Labrador sea is not as great To be certain I still need to get a link to insure that there is no chance of a Gulf Stream Meander or ring from setting up shop near by as well In the meantime here are a few links that seem to support this possibility http www gfdl noaa gov reference AR99 4OceanicCirculation html http www aoml noaa gov phod acvp peter htm http www ncdc noaa gov oa climate research 2006 sep eaimages html http nomads ncdc noaa gov ncep charts hires 20060719 gdas 250 hgt iso nh anl 00 20060719 gif http earthobservatory nasa gov Newsroom MediaAlerts 2006 2006092623268 html http nsidc org cgi bin wist wist nt pl wcf seaice index txt panel 1 http www aoml noaa gov phod acvp curry htm Dave Cooke Response See Stefan s repsonse following mine above Neither of us are saying there is no evidence of warming in the North Atlantic We re saying that jumping to the conclusion that we re seeing the beginning of a DO event is pure conjecture and contradicts pretty much everything we know about such events in the past eric 13 Nereo Preto says 9 Nov 2006 at 4 04 AM I know about a physical phenomenon called stochastic resonance Some noisy systems may greatly amplify weak signals expecially if thresholds are involved May this be the case Some unknown natural forcing exists with a period of 1470 yrs and the climate system is subject to stochastic resonance during glacials During interglacials it is not as sensitive as in glacials or thresholds are shifted to other values which are no more critical I know all this is very generic but I m not phisicist or a climatologist sorry A good understanding of this may be very important does global warming keep us out of danger of D O cycles I m not suggesting that global warming is good or it makes the whole system more sensitive We don t know of course But I d like to know if studies are ongoing on this topic This was a great post As usual but this time the argument is among my favourites Response Well good idea Our papers on DO events triggered by stochastic resonance are here and here stefan Response On the other hand please see our paper showing where the stochastic resonance idea may be wrong Don t get me wrong here I think the papers Stefan cites are important and largely correct but the statistics supporting stochastic resonance as a good model are simply not convincing at least to me eric 14 Brad Arnold says 9 Nov 2006 at 4 53 AM To reiterate according to the above article there are two types of warming one of heat distribution and the other of total heat accumulation The comment I would like to make is that an abrupt climate change that affects global heat distribution would also affect regional deforestation devegetation precipitation and desertification In other words abrupt climate change would increase rapid climate change For instance changes in ocean convection over the north Atlantic would affect the jet stream which would have a dramatic effect upon regional precipitation probably leading to acute drought in the northern hemisphere which will weaken and push the northern jet stream toward the Arctic The point I am trying to make is when it is claimed that DO events represent a much larger and more rapid climate change than anthropogenic global warming perhaps DO events do cause rapid regional climate change larger and more rapid than anthropogenic global warming generally In other words a DO event brought on this time by anthropogenic global warming should be seen as larger and more rapid climate change than anthropogenic global warming I think that temperature extremes brought on by global warming lend themselves more to rapid climate change than higher average temperature The extremes are more a matter of regional heat distribution than global heat accumulation 15 Paul Biggs says 9 Nov 2006 at 5 31 AM A 1470 year solar cycle Sounds like a plug for Singer s new book Response The 1470 year solar cycle is purely conjecture There is some evidence for millennial scale variability in the sun but it is not very strong evidence and it is not periodic eric 16 pete best says 9 Nov 2006 at 6 05 AM Great article RC just goes to show how complicated the climate is and why this site is necessary for all of us interested quasi scientific types Fantastic stuff better than buying any book and I have bought a few of em 17 jhm says 9 Nov 2006 at 7 37 AM As impressive as it is how sure are we that our growing understanding of the climate isn t on too small a time scale Having read the recent NYT article about evidence on a paleontological time scale makes me think that we might get close to underastanding climate until panama falls into the sea or some more likely but equally momentous thing happens Response That NYT article you quote is extremely misleading and in some places simply wrong We re putting up a post on that today eric 18 L David Cooke says 9 Nov 2006 at 7 56 AM RE 12 Dr Steig Here is a great link for looking at the SSTs near the Labrador Sea interface and it is clear that there is no indication of a GS deviation meander eddie or ring in the area https www navo navy mil cgi bin search pl 0 metoc 217 19 I suspect that the possible warmer temper intrusion above the NA into the Arctic appears related to the surface fetch and pooling related to the anti cyclonic zone near 30 Deg W Bermuda High Now if you back up and go look at Greenland Sea Norwegian Sea interface you can see a clear intrusion between Svalbard Is and the east coast of Greenland here https www navo navy mil cgi bin search pl 0 metoc 215 19 Whether this is a abnormally high intrusion of warmer temperatures remains an opportunity for additional study As to whether this is due to winds or GS also remains I suspect it is purely due to the force behind the GS as the increased Arctic Easterlies should push most of the warmth westward However with the Bermuda High east and slightly north it may be sufficient to drive the Gulf Stream with enough force to intrude deeper into the Arctic The important point is that this really is not news anyone with a PC and the interest should be able to see this data The tough part would be to define how or why this is occurring So far this seems to be eluding us all Please note that during most of the years in which there appeared to be significant support for GW that the Bermuda High appeared in it s Classic position of approximately 60 Deg W and 30 35 Deg N during the peak of summer and at times would retrograde towards 25 Deg N and 75 Deg W Is it possible the Rossby Wave effect on the Jet Stream is the driving force behind the NAO and PDO If so what drives the deviation of the Jet Stream Dave Cooke 19 David Fanning says 9 Nov 2006 at 11 23 AM Stefan In addition to Alley s Two Mile Time Machine another excellent book that describes the Greenland ice cores and what they might mean in terms of abrupt climate change is Climate Crash Abrupt Climate Change and What It Means for Our Future by John D Cox Cox is a science journalist albeit a good one and the book is written at about the Scientific American level Perfect for someone with a technical background coming to this topic for the first time I ve read it twice in succession because I find it so helpful for understanding and supplying context for the articles here in RealClimate 20 JimR says 9 Nov 2006 at 2 15 PM If the theory is that DO events are driven by some regularly varying external factor why would these events not be seen during the Holocene And if this is externally driven shouldn t the driver of DO events still be in play today Response In our model they only occur under glacial conditions not under Holocene conditions The reason is that the Holocene has a different pattern of ocean circulation with vigorous convection in the Greenland Norwegian Seas It s already in something like a permanent DO event state the basin is well flushed and small variations in freshwater input which accumulate under glacial conditions cannot accumulate Hence we don t get events there from the same forcing that triggers events in the glacial when the circulation is close to a threshold so a small forcing can trigger big changes stefan 21 Jim Cross says 9 Nov 2006 at 6 36 PM At the risk of being one of the non experts confounding first and second kinds of climate change I assume it is possible both could happen at once Using the bathtub analogy we could be running more water into the tub at the same time we are sloshing the water around Is there any evidence that something like this might be involved in the transitions between glacial and interglacial periods In other words there is general warming occurring at the same time ocean circulation changes to accelerate the general warming Or a general cooling accompanied by a change in flow in the opposite direction Response Absolutely During the transition from glacial to interglacial climate the evidence is that the MOC became more vigorous So in Greenland it got warmer both because of higher CO2 more sunlight at high latitudes during summer AND because of increased poleward heat flow It is still debatable just how much the increased poleward heat flow really increased but it almost certainly did change eric 22 Lynn Vincentnathan says 9 Nov 2006 at 9 59 PM I brought up GW to my anthro students and one claimed she read in SCIENCE recently that the Antarctic is cooling thus disproving GW The other claimed her father in Utah name is the leading GHG scientist and he says GW is not happening Are they tapped into some reality that most others are missing Response Some alternate reality perhaps but not this planet Antarctica cooled in the 1980s to 2000 But it was warming from the 1960s to the 1980s If you look at the overall trends 1957 2005 for most of the continent it didn t change at all on average Oh and the Antarctic Peninsula is the fastest warming place on the planet and has been for some 50 years or more None of this either proves nor disproves anything about global warming We ve had several posts on this beginning with the very first week of RealClimate Have your students read these articles here and here then come back to you As for the famous Utah professor um not anyone we know of eric 23 Brad Arnold says 10 Nov 2006 at 6 55 AM I would like to elaborate on my previous posting i e abrupt climate change vs rapid climate change and heat distribution vs total heat accumulation Dr Lovelock is known for a unifying theory of earth s eco systems In other words the gestalt of earth s eco systems He came away from a visit to the Hadley Climate Centre with a belief that earth s eco system is going to crash sooner than was conventionally believed by other scientists This is directly relevant to abrupt climate change because heat distribution unbalancing eco systems means earth will soon catch a fever I apologize for the anthropomorphic imagery In other words the total heat accumulation won t abruptly rise which is impossible per the above article but abrupt climate change will affect heat distribution which will unbalance eco systems which will led to rapid global warming i e rapid heat accumulation When it is written that within a decade or two abrupt climate change will occur and the earth will switch from the mild climate of the last ten thousand years the Holocene to a hotter dryer climate that has been responsible for mass extinctions in the past what is meant is not that total heat accumulation will instantaneously jump Instead what is meant is that heat distribution will change consequencially leading to a higher rate of total heat accumulation Abrupt climate change shouldn t be dismissed as regional and not be implicitly tied to an abrupt rise in total heat accumulation but instead should be seen as a big step toward an increased rate of total heat accumulation i e a fever Let me go farther the problem with many global climate models is they don t properly evaluate events of imbalanced heat distribution Under the right circumstances glaciers melt abruptly regional forests and soil become carbon emitters abruptly and oceanic atmospheric currents shift abruptly leading to rapid global warming In my opinion these events only work one way i e to make global warming more rapid In other words we may warm up quicker than consensis scientific opinion predicts but we are going to cool down much slower after the fever peaks 24 susan maclove says 10 Nov 2006 at 2 01 PM Changes in the atmosphere ie increased moisture levels at higher elevations are contributing in driving the climate change so I believe the ocean models need to include atmospheric data and how those combine to drive wind currents Additionally the solar energy that is now being absorbed rather than reflected in the Artic must be a major contributor to weather patterns The composition of the troposphere has been altered through manmade contributions such as exhaust from combustion engines accumulating over a more than a century and the destruction of forests which act as sinks and replenish oxygen as well as keep surface temps cooler The comparison of ice cores and postulating effects of gases and temperatures appears intriguing but one must admit that what is occurring NOW is a first in a Global lifetime Just explain how anything in the past history of the Earth can compare to the changes that have occurred in the last century Response You are right on your first point the models we use of course are coupled climate models not ocean models so they account also for changes in the atmosphere Also we do not use the past as an analogue comparing the present with ice core data to draw conclusions Rather we build a physical understanding of past changes and assume that the laws of physics stay the same stefan 25 Joseph O Sullivan says 10 Nov 2006 at 6 33 PM This was a very informative post I understand Dansgaard Oeschger events better now There is a reuters article about climate change and the climate talks in Nairobi It quotes Stefen mostly about climate change and the oceans http www enn com today html id 11633 Response The webcast of my talk in Nairobi is here http www un org webcast unfccc archive asp go 106 Look for the WBGU event on 9 November Also contains a link to the WBGU report on the oceans stefan 26 Wacki says 10 Nov 2006 at 9 03 PM Good post stefan Just curious when you say It s already in something like a permanent DO event state the basin is well flushed and small variations in

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  • Little Ice Age (“LIA”) « RealClimate
    Little Ice Age impeded the navigation of a Northwest Passage in the Canadian Arctic during the early 19th century However an exhaustive study of 19th century explorer logs for the region yields no evidence of conditions that would be considered unusually cold by modern standards See also Medieval Warm Period Comments Off on Little Ice Age LIA 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

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