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Journal of Climate: New cloud feedback results “provide support for the high end of current estimates of global climate sensitivity”

By Joe Romm  

"Journal of Climate: New cloud feedback results “provide support for the high end of current estimates of global climate sensitivity”"


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Co-author Kevin Hamilton concludes, “If our model results prove to be representative of the real global climate, then climate is actually more sensitive to perturbations by greenhouse gases than current global models predict, and even the highest warming predictions would underestimate the real change we could see.

Another day, another study that suggests we face climate impacts on the high end of current projections.

Contrary to the observation-free wishful thinking of the disinformers and confusionists, the best scientific evidence is, “Clouds Appear to Be Big, Bad Player in Global Warming” “” an amplifying feedback (sorry Lindzen and fellow deniers).  That was how Science described one major 2009 study.

A new paper in Journal of Climate, (subs. req’d), reconciles observed  cloud variations in the tropical and subtropical eastern Pacific region with climate models — and finds that, if their results are correct, “they provide support for the high end of current estimates of global climate sensitivity.”

Here are excerpts from the University of Hawaii news release, “Study could mean greater anticipated global warming” (the source of the quote above):

Current state-of-the-art global climate models predict substantial warming in response to increases in greenhouse gases such as carbon dioxide. The models, though, disagree widely in the magnitude of the warming we can expect. The disagreement among models is mainly due to the different representation of clouds. Some models predict that global mean cloud cover will increase in a warmer climate and the increased reflection of solar radiation will limit the predicted global warming. Other models predict reduced cloudiness and magnified warming. In a paper that has just appeared in the Journal of Climate, researchers from the University of Hawaii Manoa (UHM) have assessed the performance of current global models in simulating clouds and have presented a new approach to determining the expected cloud feedbacks in a warmer climate.

Lead author Axel Lauer at the International Pacific Research Center (IPRC) at UHM notes, “All the global climate models we analyzed have serious deficiencies in simulating the properties of clouds in present-day climate. It is unfortunate that the global models’ greatest weakness may be in the one aspect that is most critical for predicting the magnitude of global warming.”

To study the clouds, the researchers applied a model representing only a limited region of the atmosphere over the eastern Pacific Ocean and adjacent land areas. The clouds in this region are known to greatly influence present climate, yet current global models do poorly in representing them. The regional model, developed at the IPRC, successfully simulates key features of the region’s present-day cloud fields, including the observed response of clouds to El Nino. Having evaluated the model’s simulation of present-day conditions, the researchers examined the response of simulated clouds in a warmer climate such as it might be in 100 years from now. The tendency for clouds to thin and cloud cover to reduce was more pronounced in this model than in any of the current global models.

We continue to learn about the dangerous positive carbon-cycle feedbacks that threaten to amplify the impacts of human-caused GHGs:

  • Study: Water-vapor feedback is “strong and positive,” so we face “warming of several degrees Celsius”
  • The best evidence is that the climate is now being driven by amplifying feedbacks “” see, most notably:

    And let’s not even get started on destabilizing and venting the Vast East Siberian Arctic Shelf methane stores :  NSF issues world a wake-up call: “Release of even a fraction of the methane stored in the shelf could trigger abrupt climate warming.”

    UPDATE:  See also Lindzen debunked again: New scientific study finds his paper downplaying dangers of human-caused warming is “seriously in error”, Trenberth: The flaws in Lindzen-Choi paper “have all the appearance of the authors having contrived to get the answer they got.”


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    34 Responses to Journal of Climate: New cloud feedback results “provide support for the high end of current estimates of global climate sensitivity”

    1. Mark S says:

      Great coverage of the latest science Joe.

      Something I’ve always wondered about cloud feedback is how one would explain interglacial temperatures if the clouds were a negative feedback. It would seem that if clouds were such a big negative feedback as Lindzen, et al, suggest than we couldn’t get enough warming to get us out of ice ages.

      Anyone out there with suggestions for further reading on this for amateurs?

    2. Dana says:

      This study reminds me a lot of Clement et al. (2009) which also examined low-level cloudcover over the NE Pacific and found evidence for a positive feedback.

      We still have to be cautious though, because these are regional studies which may not translate to global cloudcover effects. Nevertheless, it certainly doesn’t bode well for the low climate sensitivity camp (Lindzen, Spencer, Christy, etc.).

      Mark #1 – you’re correct, a low climate sensitivity parameter would make it hard to explain transitions between glacial and interglacial periods. I wrote an article on climate sensitivity which discussed this a bit:

      Also reposted by Joe here:

    3. Andy says:

      And yet global temps are not responding quite as quickly as projected. The ocean’s massive heat storage capacity seems to capable of seriously mucking up future global temperature projections.

      Environmentalism is plagued with the disunion of the human life span and the speed with which the earth and populations respond to perturbations.

      The bet between Paul Erlich and Julian Simon for example, about when the earth would reach its carrying capacity and humans would begin starving. Supposedly lost by Erlich, and then trumpeted by anti-environmentalists for three decades; it’s now becoming apparent that Erlich is winning though long after Simon’s death.

      I’m guessing here, but it seems that global warming will be worse than feared and yet will still become evident slowly enough to allow us to cook ourselves.

    4. MapleLeaf says:

      MarkS @1,

      Try Sciencedaily.com. They tend to do an excellent job of communicating the science. They even featured this paper:


      You can also try skepticalscience.com.

    5. Raining in Alaska, in late November…

      I fear we are experiencing abrupt climate change right now.
      Isn’t what we’re seeing what it would look like?

    6. Lindzen made the argument in his testimony last week, that the change between glacial and interglacial could be explained without greenhouse gases, but didn’t go into any detail.
      I’d be interested to hear what his rationale is.

    7. Michael says:

      Andy (#3):

      The trend in recent years has been pretty close to projections; mind you, the expected rate of increase is still relatively small at this point, about 0.2°C per decade:


      See the second graph in particular, since many deniers claim that there has been no warming in the past 10 years, also note the dataset with the most warming.

      Also, the deep ocean has been taking up enough heat over the past 20 years to cause surface warming of 3°C per decade – in other words, we could have warmed by 6°C already if the oceans didn’t take up any heat!


      I think this solves the missing heat problem, where ocean warming (before the deep ocean was fully accounted for) wasn’t enough to account for the observed radiative imbalance and also helps explain observed sea level rise better.

    8. Michael says:

      It appears that lakes are warming faster than the global average, and faster than ocean or land temperatures, especially the latter, which I find interesting because I would expect a lake to warm faster than ocean (shallower and surrounded by land which is warming faster than ocean) but not faster than land:

      NASA Study Finds Earth’s Lakes are Warming

      They reported an average warming rate of 0.45 degrees Celsius (0.81 degrees Fahrenheit) per decade, with some lakes warming as much as 1 degree Celsius (1.8 degrees Fahrenheit) per decade. The warming trend was global, and the greatest increases were in the mid- to high-latitudes of the Northern Hemisphere.


    9. Richard L says:

      Wow – this seems to be in direct contrast with the testimony offered by Lindzen to Congress. Do top notch Universities such as MIT ever get embarrassed enough over the blatantly poor/misguided statements of their faculty to actually do something?

    10. Windsong says:

      Beam Me Up Scotty, #5, I loved your website! How do I send it via Email?! I wish I could send it to friends by email but don’t know how! Just shows twitter and facebook!

    11. Prokaryotes says:

      The Venusian atmosphere supports opaque clouds made of sulfuric acid, making optical observation of the surface impossible. Information about the topography of Venus has been obtained exclusively by radar imaging.[1] The main atmospheric gases on Venus are carbon dioxide and nitrogen. Other chemical compounds are present only in trace amounts.[1]

      The atmosphere of Venus is in a state of vigorous circulation and super-rotation.[5] The whole atmosphere circles the planet in just four Earth days, much faster than Venus’ sideral day of 243 days. The winds supporting super-rotation blow as fast as 100 m/s (~220 mph).[5] Venusian winds move at up to 60 times the speed of the planet’s rotation, while Earth’s fastest winds are only 10% to 20% rotation speed.[6] On the other hand, the wind speed becomes increasingly slower as the elevation from the surface decreases, with the breeze barely reaching the speed of 10 km/h on the surface[7]. Near the poles are anticyclonic structures called polar vortexes. Each vortex is double-eyed and shows a characteristic S-shaped pattern of clouds.[8]

      Unlike Earth, Venus lacks a magnetic field. Its ionosphere separates the atmosphere from outer space and the solar wind. This ionized layer excludes the solar magnetic field, giving Venus a distinct magnetic environment. This is considered Venus’ induced magnetosphere. Lighter gases, including water vapor, are continuously blown away by the solar wind through the induced magnetotail.[5] It is speculated that the atmosphere of Venus up to around 4 billion years ago was more like that of the Earth with liquid water on the surface. The runaway greenhouse effect may have been caused by the evaporation of the surface water and subsequent rise of the levels of other greenhouse gases

      The large amount of CO2 in the atmosphere together with water vapor and sulfur dioxide create a strong greenhouse effect, trapping solar energy and raising the surface temperature to around 740 K (467°C), hotter than any other planet in the solar system, even that of Mercury despite being located further out from the Sun and receiving only 25% of the solar energy Mercury does.

      Venus’s windspeeds can be directly measured only in the upper troposphere (tropopause), between 60–70 km, altitude, which corresponds to the upper cloud deck.[19] The cloud motion is usually observed in the ultraviolet part of the spectrum, where the contrast between clouds is the highest.[19] The linear wind speeds at this level are about 100 ± 10 m/s at lower than 50° latitude. They are retrograde in the sense that they blow in the direction of the retrograde rotation of the planet.[19] The winds quickly decrease towards the higher latitudes, eventually reaching zero at the poles. Such strong cloud-top winds cause a phenomenon known as the super-rotation of the atmosphere.[5] In other words, these high-speed winds circle the whole planet faster than the planet itself rotates.[18] The super-rotation on Venus is differential, which means that the equatorial troposphere super-rotates more slowly than the troposphere at the midlatitudes.[19] The winds also have a strong vertical gradient. They decline deep in the troposphere with the rate of 3 m/s per km.[5] The winds near the surface of Venus are much slower than that on Earth. They actually move at only a few kilometers per hour (generally less than 2 m/s and with an average of 0.3 to 1.0 m/s), but due to the high density of the atmosphere at the surface, this is still enough to transport dust and small stones across the surface, much like a slow-moving current of water.

      All winds on Venus are ultimately driven by convection.[5] Hot air rises in the equatorial zone, where solar heating is concentrated, and flows to the poles. Such an almost-planetwide overturning of the troposphere is called Hadley circulation.[5] However, the meridional air motions are much slower than zonal winds. The poleward limit of the planet wide Hadley cell on Venus is near ±60° latitudes.[5] Here air starts to descend and returns to the equator below the clouds. This interpretation is supported by the distribution of the carbon monoxide, which is also concentrated in the vicinity of ±60° latitudes.[5] Poleward of the Hadley cell a different pattern of circulation is observed. In the latitude range 60°–70° cold polar collars exist.[5][8] They are characterised by temperatures about 30–40 K lower than in the upper troposphere at nearby latitudes.[8] The lower temperature is probably caused by the upwelling of the air in them and by the resulting adiabatic cooling.[8] Such an interpretation is supported by the denser and higher clouds in the collars. The clouds lie at 70–72 km altitude in the collars—about 5 km higher than at the poles and low latitudes.[5] A connection may exist between the cold collars and high speed midlatitude jets in which winds blow as fast as 140 m/s. Such jets are a natural consequence of the Hadley–type circulation and should exist on Venus between 55–60° latitude.[19]

      Odd structures known as polar vortices lie within the cold polar collars.[5] They are giant hurricane-like storms four times larger than their terrestrial analogs. Each vortex has two “eyes”—the centers of rotation, which are connected by distinct S-shaped cloud structures. Such double eyed structures are also called polar dipoles

      The reflectivity of the clouds causes the amount of light reflected upward to be nearly the same as that coming in from above, and a probe exploring the cloud tops could harness solar energy almost as well from below as above, enabling solar cells to be fitted just about anywhere.[32]

      The cloud cover is such that very little sunlight can penetrate down to the surface, and the light level is only around 5,000–10,000 lux with a visibility of three kilometres. At this level little to no solar energy could conceivably be collected by a probe. Humidity at this level is less than 0.1%.[33] In fact, due to the thick, highly reflective cloud cover the total solar energy received by the planet is less than that of the Earth.

      Sulfuric acid is produced in the upper atmosphere by the sun’s photochemical action on carbon dioxide, sulfur dioxide, and water vapor. Ultraviolet photons of wavelengths less than 169 nm can photodissociate carbon dioxide into carbon monoxide and atomic oxygen. Atomic oxygen is highly reactive; when it reacts with sulfur dioxide, a trace component of the Venusian atmosphere, the result is sulfur trioxide, which can combine with water vapor, another trace component of Venus’ atmosphere, to yield sulfuric acid.

      CO2 → CO + O
      SO2 + O → SO3
      SO3 + H2O → H2SO4

      Venus’s sulfuric acid rain never reaches the ground, but is evaporated by the heat before reaching the surface in a phenomenon known as virga.[34] It is theorized that early volcanic activity released sulfur into the atmosphere and the high temperatures prevented it from being trapped into solid compounds on the surface as it was on the Earth.[35]

      The clouds of Venus are capable of producing lightning much like the clouds on Earth


    12. Windsong
      Thanks! It’s cathartic to me to write it.
      At the bottom of each post is an envelop icon. Click that.

    13. Wit's End says:

      I personally am predicting very rapid warming, due to

      1. melting permafrost releasing methane and

      2. forest and vegetative collapse due to tropospheric ozone pollution, which will cease to photosynthesize and constitute a major CO2 – sink and instead emit and

      3. phytoplankton decrease, which is also soaking up ozone and dying off…

      Where will the oxygen we need to breathe come from??

    14. Pete Dunkelberg says:

      Mark @ 1 mentions Lindzen and asks:
      “Anyone out there with suggestions for further reading on this for amateurs?”

      If you’re up for some world class BS, here’s Lindzen.

    15. Jeffrey Davis says:

      Climate sensitivities to changes have to be high to produce the dizzying rise in temperature we see after the trough of Milankovich cycles.

      Milankovich forcings are around an order of magnitude less than that from greenhouse gases, and yet temperatures skyrocket. Well before glaciation has completely retreated. So, the increase in temperature can’t be due simply to changes in albedo. Something is pushing those temps and pushing them hard.

    16. K Nockels says:

      The Energy Balance of Planet Earth right now is off by 0.85 watts of energy per square meter. thats how much more energy(heat) is entering the system than is being radiated back into space. The climate system is trying to dump that extra energy(heat) any way it can. +melting ice +Ocean absorbing radiative energy(heat) +Increased evaporation. There is also the increase in wind speed in the stratosphere, caused both by green house gases that trap heat below in the troposphere there by cooling the upper levels and the rising solar activity which causes UV radiation to scatter outward away from earth. As the stratosphere cools windspeed in the strato Jets increases,this affects wind speeds in the lower jets and they affect the speed of the AO and SAM both of which move lots of heat around the poles. Right now both are in overdrive.As these affects are intensify by additional gases being added to the system we will start to see those slow rises in temps start to ramp up. You simply can’t keep dumping energy into a closed system without hugh consequnces.

    17. Colorado Bob says:

      Raining in Alaska, in late November…

      Barrow AK set 2 new records Monday and Sunday ……. 33 F and 32 F .
      It was 28 F there today, one degree short of the record of 29 F.


    18. Roger says:

      Richard L. says: “Wow – this seems to be in direct contrast with the testimony offered by Lindzen to Congress. Do top notch Universities such as MIT ever get embarrassed enough over the blatantly poor/misguided statements of their faculty to actually do something?”

      Funny you should ask, Richard. I wondered the same thing, and so I asked the president of MIT about it earlier this year. Having tenure, doing something might only make matters worse, was the gist I got.

      A question: does Lindzen say he’s speaking as a private citizen, not for MIT? I notice that Jim Hansen always does this re his NASA link.
      It would seem appropriate for Lindzen to be required to do the same.



    19. MarkB says:

      As Dana notes in #2, the regional nature of the study is an important caveat, although the study notes in the abstract a reason to think it may apply globally.

      The broad range of studies still indicate a best estimate of around 3 C.


    20. riverat says:

      Beam Me Up Scotty says: November 23, 2010 at 6:34 pm

      Raining in Alaska, in late November…

      And in Western Oregon and Washington we’ve had a blast of Arctic air and a half inch of snow, before Thanksgiving! Kind of like last year when it was frigid in the Southeast US and warm in Greenland.

    21. Heraclitus says:

      What’s the betting that if Kevin Hamilton’s quote had been

      “If our model results prove to be representative of the real global climate, then climate is actually less sensitive to perturbations by greenhouse gases than current global models predict, and even the lowest warming predictions would overestimate the real change we could see.”

      we would be reading about this in every paper by now? It’s early days I suppose, but I’m not holding my breath. After all, how could this paper as it stands be seen to provide balance? What possible use is it to a journalist?

    22. bratisla says:

      @Heraclitus, this is not journalism, this is science. Either you find a good model for observations and you have “won”, or your model fails and thus you have “lost” and must go back to the drawing board. No the “first paragraph pro, second paragraph against, third paragraph let’s mix water and all is balanced and fair” journalism gibberish. Science is war, do something useful or go to hell.

      If Hamilton had found a lower sensitivity from his study :
      - either it would have been supported by other pieces of evidence and it fitted nicely in the picture, and therefore his model is OK (for the moment)
      - or it contradicts what was assumed before, and things get serious : either after much scrutiny he was right and a lot of work awaits his colleagues, or he was deadly wrong and his paper is dumped.

      Guess in which category fall Lindzen, Courtillot and other scientific climatosocalledsceptics. No wonder they ask for court-style hearings, instead of scientific debates : they know that court-style hearings allow them to “mix water” whereas scientific debates will turn to their disadvantage.

    23. perceptiventity says:

      ((( ; indeed Heraclitus, very funny. They might be dragging their heels to have another generation remember just this violent EAaarth that’s comig our way. “Normal” size for fish is already almost caviar compared to 1860, heck even to 1960

    24. Lewis C says:

      “NSF issues world a wake-up call: “Release of even a fraction of the methane stored in the shelf could trigger abrupt climate warming.”

      It grieves me to see respected organizations using such a fatuous cliche as
      “climate warming”
      particularly when various sources project an exceptionally extreme winter for parts of the northern hemisphere this year.

      A good fraction of the messaging problem was set up by the politicians who, with scientists’ acquiesence, established the terms “Global Warming” and “Climate Change”. Neither is scientifically specific nor helpful in informing the society of its jeopardy.

      What we face is of course actually “Global Heating”, and consequent “Climate Destabilization”. Using fuzzier terms is merely an advanced form of denialism. The sooner scientists, activists, businessmen, journalists, and others start using the scientifically descriptive terms, the better our chance of society mandating the vital geo-political changes required before the feedbacks exceed any possibility of control.



    25. Heraclitus says:

      Sorry, I left out the sarc tags on the last two sentences of my post above.

    26. Andy says:

      Lewis C. #24,

      “Climate destabilization” is a great term, of course, and is perhaps a more precise form of the term “global weirding” that Tom Freidman has advocated.

      But really, what’s the difference between “global heating” and “global warming”? Surely it can’t be something that would substantially improve the understanding of the general public, were a change in terminology to occur.

    27. perceptiventity says:

      if only we could distabilise convictions of the folks who gleefuly commented on this news story …


      And it’s Methane on the rise again, by the by! Congrats .
      It is in an alaskan newspaper but locals cant be bothered mostly. If we do not want it to happen it just won’t. Until some major port succumbs to erosion probably ?

    28. mike roddy says:

      If US forests stop being sinks- already happening in some regions- our emissions will increase substantially. Diverse stands- now rare at landscape scale- offer the best resistance to fire and pests.

    29. Mark S says:

      pete, mapleleaf, thanks for the reading suggestions. And that was some world class BS in the Lindzen paper…

    30. Mark S WRT that Heartland Institute Lindzen paper I quite agree, there is enough humbug on the first page to see where the rest is going. One statement at the foot of that page takes the tone down further than his comments under ‘triage‘ and ‘opportunism of the weak‘.

      From the point of view of serious science, this group is mostly a nuisance, but they play a major role in the maintenance of alarm.

      To accuse those risking life and enduring harsh conditions to collect the data about the organisms that share this planet with us and to whose continued species existence our own future survival depends of being ‘mostly a nuisance’ because ‘they play a role in the maintenance of alarm’ tells us that Lindzen is not worthy of future consideration.

      The more I hear and read this person the less likeable he becomes. Disgraceful! He should be made to endure a session at Palmer Station on the Antarctic Peninsula.

      The more I hear and read this person the less likeable he becomes.


    31. Andy Revkin says:

      I don’t have time to post on this today but I did send a note to NCAR’s Kevin Trenberth, a frequent source of Joe’s (and mine), and here’s his reply, which says heaps about paying too much attention to one study, particularly of one region:

      [JR: Normally I don't post comments that so blatantly misrepresent what I wrote. The point of this post was 1) it is consistent with other recent results (unlike the work of, say, Lindzen) and 2) it marries observation with theory in the crucial area. But I'll run this because of Trenberth's comment.

      That said, the point is this matches up observation with models in one key part of the planet. It seems to me Trenberth may have read it a tad quickly and missed this point.]

      “I am not familiar with this work and I just read the link you sent. The problem is not unfamiliar and we have analyzed it extensively: see especially:
      Trenberth, K. E., and J. T. Fasullo, 2009: Global warming due to increasing absorbed solar radiation. Geophys. Res. Lttrs., 36, L07706, doi:10.1029/2009GL037527.

      Trenberth, K. E., and J. T. Fasullo, 2010: Simulation of present day and 21st century energy budgets of the southern oceans. J. Climate, 23, No. 2, 440-454.

      Both of which deal with clouds and model errors. The statement in the write up is wrong: all models tend to have a positive feedback effect from clouds. The reasons are known but there is no confidence that the result is correct.

      Here is a quote from the first paper:
      Nevertheless, this raises the question of whether
      warming could be offset by increased low-level cloud cover
      as a negative cloud feedback [Miller, 1997]. Observations
      suggest that cloud undergoes a decrease in optical depth and
      positive SW CRF as temperatures rise [Tselioudis and
      Rossow, 1994], and the seasonal cycle, El Nin˜o-related
      variations and other changes show that SW CRF decreases
      as SSTs rise in large-scale subsidence regimes [Bony et al.,
      2004; Bony and Dufresne, 2005]. However, these studies do
      not provide information on how low clouds should respond
      when other aspects such as the large-scale dynamics, lapse rate
      and temperature inversions also change [Miller, 1997].

      The trouble with the study is that it deals only with a region and that region is not independent of other places. As the clouds change in that region the larger scale atmospheric circulation changes and it may change in other directions elsewhere. You can not do this reliably with a regional model.”

    32. Edward says:

      So what is the new sensitivity?

    33. Steve Bloom says:

      Re #19: Mark, Knutti has a new paper aimed at knocking out the low-sens models, basically because they fail to warm the Barents Sea consistent with observations. Not warming the Barents means they can’t be getting Arctic amplification right.

      Re Lindzen, this has to be about the 10th stake in the heart of his ideas in the last couple of years. Yet another one came out a few weeks ago.

    34. Steve Bloom says:

      Joe, does your spam filter moonlight for TSA?