This study is being listed as proof by some of the usual alarmist types that the issue of cloud feedback is settled. Before accepting that, read this from the summary in the June 24th issue of Science by Richard A. Kerr:
The first reliable analysis of cloud behavior over past decades suggests—but falls short of proving—that clouds are strongly amplifying global warming. If that’s true, then almost all climate models have got it wrong. On page 460, climate researchers consider the two best, long-term records of cloud behavior over a rectangle of ocean that nearly spans the subtropics between Hawaii and Mexico. In a warming episode that started around 1976, ship-based data showed that cloud cover—especially low-altitude cloud layers—decreased in the study area as ocean temperatures rose and atmospheric pressure fell. One interpretation, the researchers say, is that the warming ocean was transferring heat to the overlying atmosphere, thinning out the low-lying clouds to let in more sunlight that further warmed the ocean. That’s a positive or amplifying feedback. During a cooling event in the late 1990s, both data sets recorded just the opposite changes—exactly what would happen if the same amplifying process were operating in reverse.
Here’s the press release. I’ve looked at a few news writeups on it, and the caution listed in Science about it not being proven seems to be off the reporting radar. We’ll need further studies on a global scale, and not just one patch of ocean, before the question can be fully answered. – Anthony
From Physorg.com
The role of clouds in climate change has been a major question for decades. As the earth warms under increasing greenhouse gases, it is not known whether clouds will dissipate, letting in more of the sun’s heat energy and making the earth warm even faster, or whether cloud cover will increase, blocking the Sun’s rays and actually slowing down global warming.
In a study published in the July 24 issue of Science, researchers Amy Clement and Robert Burgman from the University of Miami’s Rosenstiel School of Marine and Atmospheric Science and Joel Norris from Scripps Institution of Oceanography at UC San Diego begin to unravel this mystery. Using observational data collected over the last 50 years and complex climate models, the team has established that low-level stratiform clouds appear to dissipate as the ocean warms, indicating that changes in these clouds may enhance the warming of the planet.
Because of inconsistencies in historical observations, trends in cloudiness have been difficult to identify. The team broke through this cloud conundrum by removing errors from cloud records and using multiple data sources for the northeast Pacific Ocean, one of the most well-studied areas of low-level stratiform clouds in the world. The result of their analysis was a surprising degree of agreement between two multi-decade datasets that were not only independent of each other, but that employed fundamentally different measurement methods. One set consisted of collected visual observations from ships over the last 50 years, and the other was based on data collected from weather satellites.
“The agreement we found between the surface-based observations and the satellite data was almost shocking,” said Clement, a professor of meteorology and physical oceanography at the University of Miami, and winner of the American Geophysical Union’s 2007 Macelwane Award for her groundbreaking work on climate change. “These are subtle changes that take place over decades. It is extremely encouraging that a satellite passing miles above the earth would document the same thing as sailors looking up at a cloudy sky from the deck of a ship.”
What was not so encouraging, however, was the fact that most of the state-of-the-art climate models from modeling centers around the world do not reproduce this cloud behavior. Only one, the Hadley Centre model from the U.K. Met Office, was able to reproduce the observations. “We have a long way to go in getting the models right, but the Hadley Centre model results can help point us in the right direction,” said co-author Burgman, a research scientist at the University of Miami.
Together, the observations and the Hadley Centre model results provide evidence that low-level stratiform clouds, which currently shield the earth from the sun’s radiation, may dissipate in warming climates, allowing the oceans to further heat up, which would then cause more cloud dissipation.
“This is somewhat of a vicious cycle potentially exacerbating global warming,” said Clement. “But these findings provide a new way of looking at clouds changes. This can help to improve the simulation of clouds in climate models, which will lead to more accurate projections of future climate changes. ”
One key finding in the study is that it is not the warming of the ocean alone that reduces cloudiness — a weakening of the trade winds also appears to play a critical role. All models predict a warming ocean, but if they don’t have the correct relationship between clouds and atmospheric circulation, they won’t produce a realistic cloud response.
“I am optimistic that there will be major progress in understanding global cloud changes during the next several years,” said Norris. “The representation of clouds in models is improving, and observational records are being reprocessed to remove spurious variability associated with satellite changes and other problems.”
Source: University of Miami (news : web)
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The Drudge Report has a new story on 3,000 record low temps set in July. This is one of the maps from the article: click
The more people that click on the Drudge link, the more likely that he will report similar stories.
Can’t hurt. Might help.
This stuff is getting awfully depressing. Scanning through the recent posts stack I was moved to try and come up with something from history that compares to climate science over the last quarter of a century. Where humanity has invested vast amounts of money, time, and effort, with so little tangible advancement as a result. The effort has been comparable to the Manhattan or Apollo projects, and, if worldwide expenditures are included, probably dwarfs both of them, yet the little actual advancement of the state of knowledge has mostly come from people outside the funding loop. It’s as if some guy working in his garage banged out a couple of A-bombs better than Fat Man and Little Boy or was waiting on the Moon to hang leis around the necks of Armstrong and Aldrin when they touched down.
If you google Eisenhower’s farewell address, you’ll get a boatload of hits that feature his warning about the dangers of the military-industrial complex, but what is mostly forgotten is what came immediately after that warning. He also warned about the danger inherent in government becoming the primary source of funding and control of science and research. The events of recent months have shown how fundamentally backasswards history’s reading of that speech has been. Driven by the science-government nexus, the administration and Congress are whipping us down the road to economic ruin and fundamental loss of freedom, while the military-industrial complex has labored vainly to avoid drastic procurement cuts which will lead to the destruction of more jobs than all of Waxman-Markey’s alt energy boondoggles could ever hope to replace.
Does anyone doubt that if, instead of being driven by political agendas, climate science had pursued a Feynmann like model of collecting the best available data and following it where it led, our knowledge would not have advanced well beyond its’ present sorry state. That if climate modelers had been less focused on making their models confirm the A in AGW, than with having them truly reflect the actual climate, the models would still find clouds to be such an utter mystery.
Unfortunately the politicians have now learned how useful and powerful the manipulation of science can be as tool for advancing their goals and the odds of them being convinced to abandon that power are essentially nil, which is why I find this crap so depressing.
I downloaded the COADS Ocean SST and cloud cover data for this region (monthly rather than annual) and I do not see the relationship proposed in this paper.
There is rising SSTs and rising cloud cover (about at the same rate generally with the typical variability one normally sees in ocean SST datasets).
Obviously, the data needed to be adjusted.
Bill Illis (15:39:41)
Bill, does the cloud data distinguish between clouds at different levels ?
Warmer SSTs will dissipate low cloud but provoke more evaporation and convection with the development of more, higher clouds than would otherwise have been the case.
I would expect the net effect to be negative. Higher clouds alter albedo more than do lower clouds.
Bill, where did you download the COADS SST data and the cloud cover data?
w.
RICH (14:47:46):
There are several incorrect statements or assumptions in your post:
(1) You cannot say for sure that the whole temperature drop in the day or rise at night there was due to clouds. I will agree that the significant decrease in the diurnal temperature DIFFERENCE was very likely due to clouds since they tend to cool during the day and warm at night. However, the overall temperature departures could be due to many other things such as general weather patterns. And, in general, it would be too simplistic to think of one location as providing a rigorous test anyway since there are too many other methods of heat transfer (such as advection) playing a large role in determining the local temperature.
(2) In fact, we know that in the absence of greenhouse gases, the average surface temperature of the earth would have to be close to the blackbody radiating temperature needed to have the outgoing radiation balance the incoming solar radiation. (In fact, for technical mathematical reasons, the blackbody temperature should provide an upper bound.) For the earth’s current albedo (reflectance) of ~0.3, that blackbody radiating temperature would be ~255 K, which is about 33 K below the observed average temperature of ~288 K. Admittedly, however, some of that albedo is due to clouds. However, even if we use what the earth’s albedo would be in the absence of clouds, which is apparently ~0.09, we still get a blackbody temperature of ~272 K, i.e., well below the observed surface temperature. (And, even 0 albedo gives a blackbody temperature almost 10 K below the observed average surface temperature.) What this shows us is that, in fact, the warming due to greenhouse gases (primarily from water in both its vapor and cloud forms and CO2) is larger than the cooling due to the increased albedo that the clouds provide.
From the above, I got that all climate models – bar one – are wrong. “We have a long way to go in getting the models right” and yet Gavin Schmitt can use a climate model to come to the “robust” conclusion that the sun plays only a small role???
If I am following the above paper correctly, its a chicken and egg issue. Was the warming sea clearing the sky, or was the clearer sky warming the sea?
Answer? Which ever one results in a positive feedback and media attention.
RICH (14:47:46) : Even at freezing temperatures water vapor is in the air. I wonder if all the CO2 were removed, would the Earth really freeze? Would there be enough water vapor in the air to keep atmospheric temps up? For this scenario, I am assuming the Earth isn’t covered in ice and snow.
Charlie (12:38:05) : Obviously, clouds scatter visible light, light that would not make it to the surface to become IR. Wouldn’t that be a short term negative feedback? (Or is it forcing?)
Joel Shore (16:40:56), good to hear from you. However, there is an incorrect statement or assumption on your part. You say:
Certainly, this is true at cold temperatures, because tropical clouds are a function of temperature. At cold temperatures, cumulus and cumulonimbus (thunderstorms) do not form. Thus, as you correctly state, the warming of the GHGs (primarily water vapour) is larger than the cooling effect of the clouds. This starts to warm the tropical ocean, and thus the planet. However, you are only telling half the story.
Consider what happens as temperatures increase. As the tropical ocean warms, cumulus form, reflecting heat. As the warming continues, cumulonimbus start to form.
The cumulonimbus do not simply cool by reflecting sunlight, as cumulus do. They cool by a host of very effective mechanisms, including:
1. Wind driven evaporative cooling. Once the thunderstorm starts, it creates its own wind around the base. This self-generated wind increases evaporation in several ways, particularly over the ocean.
a) Evaporation rises linearly with wind speed. At a typical squall wind speed of 10 mps (20 knots), evaporation is about ten times higher than at “calm” conditions (conventionally taken as 1 mps).
b) The wind increases evaporation by creating spray and foam, and by blowing water off of trees and leaves. These greatly increase the evaporative surface area, because the total surface area of the millions of droplets is evaporating as well as the actual surface itself.
c) To a lesser extent, surface area is also increased by wind-created waves (a wavy surface has larger evaporative area than a flat surface).
d) Wind created waves in turn greatly increase turbulence in the boundary layer. This increases evaporation by mixing dry air down to the surface and moist air upwards.
e) As spray rapidly warms to air temperature, which in the tropics is often warmer than ocean temperature, evaporation also rises above the sea surface evaporation rate.
2. Wind driven albedo increase. The white spray, foam, spindrift, changing angles of incidence, and white breaking wave tops greatly increase the albedo of the sea surface. This reduces the energy absorbed by the ocean.
3. Cold rain and cold wind. As the moist air rises inside the thunderstorm’s heat pipe, water condenses and falls. Since the water is originating from condensing or freezing temperatures aloft, it cools the lower atmosphere it falls through, and it cools the surface when it hits. In addition, the falling rain entrains a cold wind. This cold wind blows radially outwards from the center of the falling rain, cooling the surrounding area.
4. Increased reflective area. White fluffy cumulus clouds are not tall, so basically they only reflect from the tops. On the other hand, the vertical pipe of the thunderstorm reflects sunlight along its entire length. This means that thunderstorms shade an area of the ocean out of proportion to their footprint, particularly in the late afternoon.
5. Modification of upper tropospheric ice crystal cloud amounts (Linden 2001, Spencer 2007) . These clouds form from the tiny ice particles that come out of the smokestack of the thunderstorm heat engines. It appears that the regulation of these clouds has a large effect, as they are thought to warm (through IR absorption) more than they cool (through reflection).
6. Enhanced night-time radiation. Unlike long-lived stratus clouds, cumulus and cumulonimbus generally die out and vanish as the night cools, leading to the typically clear skies at dawn. This allows greatly increased nighttime surface radiative cooling to space.
7. Delivery of dry air to the surface. The air being sucked from the surface and lifted to altitude is counterbalanced by a descending flow of replacement air emitted from the top of the thunderstorm. This descending air has had the majority of the water vapor stripped out of it inside the thunderstorm, so it is relatively dry. The dryer the air, the more moisture it can pick up for the next trip to the sky. This increases the evaporative cooling of the surface.
The combination of the cumulus and cumulonimbus act together to put an effective cap on the temperature rise. If the temperature rises beyond a certain point, the rapidly increasing clouds and thunderstorms bring the temperature back down.
If the temperature falls that certain point, on the other hand, the mechanism you have correctly described in your email (GHG warming being greater than cloud cooling) takes over and raises the temperature. See, for example, Bounds on the Earth’s Surface Temperature: From the Perspective of a Conceptual Global-Mean Model for a description and a model of this process.
As a result, the global temperature stays within a narrow band. You have correctly described half of the mechanism … but you have neglected to consider the other half of the mechanism. So you are 100% right, but only half the time. As with many, many physical systems, the primary mechanisms operating above equilibrium are different from those operating below equilibrium.
My best to you,
w.
Sorry, I meant to say I downloaded the COADS data from the Climate Explorer. Someone else should replicate this in case I did something wrong.
http://climexp.knmi.nl/selectfield_obs.cgi?someone@somewhere
There is also low level, medium and high cloud data available from the Climate Explorer but it only covers 1983 to 2006. It is inconsistent with the COADS data.
Did I read it right that this study stopped in 1995? Right before the 1997-98 El Nino?
Bill Illis (15:39:41), I just did the exercise, and I agree with you
I downloaded the data myself and found a positive correlation between total cloud cover and SST … what’s up with that? Now, they’re looking at just low clouds … but according to their paper, both COADS total clouds and COADS low clouds are strongly positively correlated with each other, and both are strongly negatively correlated with SST. I do not find that at all.
WUWT???
I don’t get anything like what they show. I get both sea surface temperatures and clouds increasing over the period 1947-2007, quite unlike what they show. I can only get a negative correlation if I detrend both datasets … but why would you want to do that?
In short, the study looks like it might be destined for the Journal of Irreproducible Results …
w.
PS – I wrote a letter to the editor of Science Magazine, pointing out that the autocorrelation of the data means that the effective N is 2 and 3 … we’ll see if it makes it through the door.
As Dr Spencer points out the study encompasses a region that correlates with the descending portion of air (Hadley cell) that originated in the tropics as ascending air at the ITCZ. Therefore the region is associated with adiabatic heating, low relative humidity and of course deserts. Living in Denver I am well acquainted with chinooks which allow us to golf in January. Chinooks are also associated with clear skies because of the increased temperatures and low humidity. Therefore I suggest that perhaps periods of decreased cloud cover are related to periods of adiabatic heating due to unusually strong descending air.
Why don’t clouds form when sunlight warms the ocean? As water evaporates, it is carried to higher altitudes, given that heat rises, and that there is no temperature inversion. The water vapor-laden air cools as it rises and, at some point, can no longer hold the water vapor. Condensation occurs. Clouds form. Why not in this instance? Is the warm air not rising? Has some unknown mechanism caused adiabatic lapse rates to stop functioning?
Could it be that winds carried the moisure-rich air (laterally) to areas of cooler temperatures, to thereby rise and form clouds as usual? Do areas adjacent to the affected area have cloud cover more dense than might otherwise be explained?
lulo (00:48:10) :
Maybe a change from 1367 to 1361 W/m2 isn’t a big deal until the very slight cooling causes more cloud and it cools more. The reverse would be true as well.
There is no change from 1367 to 1361. Different spacecraft have different calibration. The ‘real’ changes are only of the order of 1 W/m2.
Jim (17:51:39) : It is important to remember that WV is bounded by the Clausius-Clapeyron Relation, so warmer parts of the atmosphere do tend to have higher Specific Humidity. The air would have to be very cold not to have any WV at all.
The fact that there is a temperature bound on WV does not mean that one can apply that bound to feedback analysis and assume that an atmosphere which can hold more WV automatically will (note that the atmosphere presently does not hold as much WV as it potentially could). Nevertheless I would still regard the WV and Ice-Albedo feedbacks as some of the more sensible positive feedbacks thought to exist (actually, Ice Albedo feedback is so obvious that the shock would be if it didn’t operate) and the more important question is cloud effects. I suspect that we are coming close to proving that these tend to be strongly negative.
You know, I just had an interesting thought. Even if there are no changes in clouds or WV at all, by their mere presence they act as a hemispheric scale negative feedback to the daily temperature cycle-since the albedo effects exceed the greenhouse effects during the daylight hours, clouds keep days on Earth cooler than they normally would be. During the night, only the longwave matters, so the same clouds will keep the nights warmer than they would be. Clearly simply by virtue of their existence, Clouds moderate the Earth’s temperature swings, making life on Earth much more tolerable. As occasional commenter here and at CA kim often says “I think I’ve never heard so loud, the quiet message of a cloud…”
richcar (20:20:21) : adiabatic heating
The coasts of southern California, northern Chile and adjacent Peru, and Namibia are located such that some of the following occur
a: there can be cold surface water off shore
b. or not
c: there can be winds carrying high humidity air over a warm ocean toward the coast
d. there can be high pressure zones inland and air can flow out toward the ocean from higher altitude (think S. CA’s Santa Ana wind) producing adiabatic warming
e. any of these things may not happen
Seasonally and over longer periods these patterns shift. When high pressure shifts to be over the ocean as does STHP there does not exist the mechanisms for cloud formation, rather stagnation and haze. When the air from over the ocean blows toward the land and flows over the cold water fog and low clouds form but the air also chills, and …
Remember the term troposphere means that layer of the atmosphere that turns over – because it is warmed at the surface and cooler above.
When the cold water chills the air just above it, then higher up the air is warmer – a temperature inversion – and the foggy/cloudy air won’t rise.
These things are not mysteries but they do shift and change over time and space enough to confound anyone looking for simple answers to difficult questions. Explanations for the uninitiated can be found at sources such as:
http://www.physicalgeography.net/fundamentals/7p.html
From your statement it is hard to tell what level of training you bring to these issues. I apologize if I missed on the down side, but even so, maybe someone else will find the above site just what they need. John
NOGW,
I’m confused. Chart no. 3 of the Svensmark article shows Cosmic Rays, and Clouds starting to build in 1992. They steadily build until 98′, when you end up with a Monster El Nino, and the hottest (or, at least, 2nd hottest) year in at least 800 years.
Isn’t this exactly opposite of what one would expect?
JeffM, I’m not a sailor, but my experiance is, “Air doesn’t get as hot over water.”
The sun heats rock, and sand quickly. The ocean, of course, is very deep. It heats much more slowly. You don’t have the super-heated air to “take off” and form thunderstorms.
I guess, however, the water starts of warmer in the tropics, and there is more water vapor in the atmosphere which starts the process from a higher level.
I see the AGW crowd are still whipping the dead horse, trying to get it to push the ambulance cart carrying their dying hypothesis back to the lab for a shot of ECT.
John Hultquist,
Thanks for the link to the reference on general circulation models. I was simply trying to address Dr Spencers query as to whether lack of clouds drive SST warming rather than the other way around as the study proposes. Descending warming air can dissipate clouds, feed trade winds, allowing for enhanced radiative warming of the ocean as well as enhanceed escaping long wave radiation at night.
“We have a long way to go in getting the models right, but the Hadley Centre model results can help point us in the right direction,”
But give us another 20 years and another 80 billion dollars and, we might turn up something.
Meanwhile, I have found a method to reconstruct global temperature history from two variables. The sunspot number, and length of day variation.
http://s630.photobucket.com/albums/uu21/stroller-2009/?action=view¤t=temp-hist-80.gif
As you can see, issues around the cooling water intake sensors on WWII ships have yet to be resolved.
Further, I have discovered that LOD variation relates to the motion of the sun with respect to the solar system barycentre, but talk of that is discouraged here.
So in a nutshell, its the planets and the sun that determine earths temperature.
Clouds just shift heat around inside the system, and this local study reveals naff all about the global situation.
You know, even if this cloud amplification of warming thing was true it would act on any warming that had an impact on the oceans, not just man-made warming, and certainly not just warming from CO2. So multiplying the impact of CO2 by some amplification factor but not doing the same thing for natural sources of warming is a tad hypocritical.
Clouds are a lot like CO2 and ozone. Both are NOT well mixed. They move here and there, up and down, and thin like gauze or glob together in drifts and pillows, blown by whatever wind and heat column is or is not around. The clouds in the above study may be giving the wrong impression to the investigators. They didn’t disappear, they moved outside the rectangle they studied. In my opinion, this is a very poor study and peer review is at best suspect, and at worst, absent.
Berry R says:
And, you get the idea that this is what the climate models do from where exactly?!?