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)
I still don’t understand why these people don’t see the obvious. If there really was a positive feedback mechanism, then we would not be here. Temperatures would have run away millions of years ago.
The albedo data give a complicated global picture than this local announcement for the last twenty years or so, :
http://bbso.njit.edu/Research/EarthShine/literature/Palle_etal_2006_EOS.pdf
Fig 2 in: Can Earth’s Albedo and Surface
Temperatures Increase Together?
Patrick Davis (03:46:24) :
“John in NZ (01:00:51) :
“OT but breaking news, NZ government has announced a target of 20% reduction of GHG by 2020.”
But NZ is the land of the long white cloud, Ao te Aroa. It’s only right that it should pay more.
Or was that a Spoonerism for the land of the wrong white crowd in Parliament?
J.Hansford (22:05:26) :
I’m no scientist, but it seems the AGW activists are trying to muddy the waters in an attempt to counter Bob Carter, De freitas, McLean, and their paper showing that the extra El Nino’s are responsible for the warming of the atmosphere from 1977 till 1998….
===
The largest thing they are NOT addressing is WHY the El Nino/La Nina changes are occurring during this period west of this same region – greatly affecting temperatures not only right in the area around the little region they are studying so closely, but rising temp’s and then dropping average local temp’s enough to affect worldwide averages.
They cannot realistically talk about cloud changes during this time period WITHOUT explicitly relating them to the El Nino cycle!
Yet another simplistic de-meteorologized study… reality must be too painful for these people.
5th grade Science text: “Clouds form as a result of ocean breezes laden with moisture moving on shore and condensing into clouds.” You must have water vapor. Water vapor comes from bodies of water. When seas are warm and calm, water vapor sufficient to produce clouds are not present. When seas are choppy and cool, water vapor sufficient to produce clouds is present.
By the way, Red skies at morning, sailor’s warning, red skies at night, sailor’s delight is a pretty good sailing indication in the mid-latitudes (not the tropics). Just for fun, here it is:
http://www.theweatherprediction.com/habyhints/139/
3000 record lows set in continental US so far in July.
[Have a look at the neqr coastal water temps in the Atlantic, too.
I do believe our Little Minimum has his father’s eyes (Al Gore), roughly the color of your fingers just before they get frost-bitten.
http://www.accuweather.com/mt-news-blogs.asp?blog=weathermatrix&partner=&pgUrl=/mtweb/content/weathermatrix/archives/2009/07/1000_low_temp_records_set_this_july.asp
Lightning shows on radar so it should be possible to due a running index of active equatorial cu-nim?
High activity I’d expect to increase trade winds and hence equatorial heat transfer to the Hadley cells. Simply taking the heat away faster won’t necessarily lower SSTs if warmer water is surfacing.
A trade-wind/ITCZ Cu-Nim connection with some idea of the direction of causation would be useful. I’d guess and only a guess that a sharp increase in Cu-nim activity would show up 2-3 days later in trade winds.
Good thread, excellent comments. My first reaction to the study was the same as many comments… there is a HUGE assumption that less clouds are caused by more surface heat. If the study does not prove a causation effect then they can’t effectively reach their positive feedback conclusions.
This is getting ridiculous. Spencer and Braswell (2008) has been out for a year now, and people are still looking at the gross relationships between clouds and temperature as not partly, not mostly, but ENTIRELY indicative of feedback!
It’s funny though-Lindzen found the Iris in a similarly small study area (Kwajalein radar) having previous identified it in a broader region with a geostationary satellite (that is, Lindzen et al. 2001). The reaction? Crickets.
http://www.agu.org/pubs/crossref/2008/2008JD010064.shtml
This is an interesting area of the ocean. See my year-long average of satellite photos at The Thermometer Hypothesis, which shows that this particular area of the ocean is unusual in that it has a semi-permanent cloud cover. This is the only part of the Pacific in this latitude band that shows this feature.
This, of course, limits the general applicability of the finding.
The part of the study that I didn’t understand is why they looked at long-term temperature changes rather than daily temperature changes. By taking an average of morning photos and afternoon photos of the area, they would be able to get a strong temperature signal which would reveal if the correlation is real.
Next, they claim to have adjusted the data for autocorrelation … but they have not said how they did it. What they say is:
So (as is my wont, and as I advise everyone to do) I took a look for myself. I first digitized the data. Here it is:
Year, COADS low cloud, COADS Sea Surf Temp
1953, -2.592, -0.3642
1954, 0.166, -0.4877
1955, 1.5, -0.7346
1956, 0.522, -0.5617
1957, -3.036, 0.0926
1958, -6.061, 0.5741
1959, -5.171, 0.537
1960, -0.902, 0.1296
1961, 2.923, -0.3025
1962, 3.813, -0.3765
1963, 2.923, -0.2407
1964, 3.457, -0.2654
1965, 3.635, -0.2037
1966, 1.589, 0.1173
1967, -0.368, 0.3642
1968, -0.724, 0.3395
1969, 1.5, 0.0432
1970, 3.724, -0.3765
1971, 5.058, -0.5741
1972, 5.859, -0.5
1973, 6.125, -0.4259
1974, 6.837, -0.6852
1975, 6.214, -0.7963
1976, 3.368, -0.4383
1977, 1.055, -0.0185
1978, -0.457, 0.1667
1979, -1.524, 0.1296
1980, -1.791, 0.1543
1981, -1.346, 0.2778
1982, -0.724, 0.2654
1983, -0.99, 0.1667
1984, -1.257, 0.1667
1985, -1.613, 0.4259
1986, -3.125, 0.537
1987, -2.147, 0.3395
1988, -0.902, 0.1667
1989, -0.724, 0.2284
1990, 0.788, 0.3395
1991, 0.788, 0.4259
1992, -2.147, 0.6358
1993, -2.681, 0.7469
1994, -1.257, 0.5988
1995, -2.147, 0.463
Using the Nychka method, the adjusted number of degrees of freedom in the cloud dataset is 2 … and in the SST dataset it is 3. This is far, far, far from being able to establish significance. Do the math yourselves, but unless I’ve made some kind of bozo mistake, their claim of statistically significant correlation is simply not true.
However, even if we were to accept their findings as real, I have another problem with their data. This is that it claims that a half-degree change in SST drops cloud cover by 5%. But my photo average at The Temperature Hypothesis shows extensive cloud cover in the afternoon, when SST is at its highest … makes it doubtful.
Not a mystery. The earth removes excess heat by removing water from the atmosphere. The Hadley circulation intensifies, supplying more dry area to the near-tropic desert zones. This thins the clouds, but also removes water vapor which is the ultimate greenhouse gas. Radiation from the surface through the atmospheric “clear window” increases markedly. Now the earth is closer to being greenhouse gas free and cooler as a result.
The observations will stand up. The conclusions won’t.
I am struck by how much water vapor is in the air in the tropics these days.
http://weather.unisys.com/satellite/sat_wv_hem.html
The earth is trying to conserve heat.
The suggestion from some sceptics seems to be that cloud dissipates first, then extra solar shortwave warms the ocean surfaces then El Nino occurs and warms the air. In relation to the Svensmark idea it is the variation in cosmic ray intensity that causes cloudiness to increase or decrease.
The suggestion from AGW proponents is that extra downwelling IR from extra GHGs causes the sea surface temperatures to rise which inhibits the normal energy flow from ocean to air so oceans warm up which warms the air.
I disagree with both scenarios. The PDO phase shifts at approximately 30 year intervals fail to show any correlation with changes in cosmic ray intensities or CO2 emissions yet on multidecadal time scales it is clearly those phase shifts that induce changes in global air tempearture trend from warming to cooling and vice versa.
It is clear to me that what has to be happening is a regular switch by the oceans from increased rates of energy emission to the air to reduced rates and in due course back to increased rates again.
The mechanism for that remains to be ascertained but it is not driven by CO2 or any other GHG or variations in cosmic ray intensity.
Those oceanic changes in phase are not adequately described by terms such as ‘PDO’ because technically that is just a statistical artifact.
I propose that there are thus far inadequately identified changes within the oceans that generate periodical changes in the net amount of stored solar energy released to the air and that drives everything we observe within the climate system (I have previously, rather tongue in cheek, suggested the term ‘Wildean Ocean Cycles’)
Those changes profoundly affect the rate of energy flow from oceans to air to space via the size and position of all the air circulation systems combined and affect the speed of the hydrological cycle which is the primary energy transfer mechanism in the air.
The residual background trend on century timescales is adequately dealt with by slow incremental changes in solar output. Hence the progression from Roman Warm Period to Dark Ages to Mediaeval Warm Period to Little Ice Age to Modern Maximum.
We do not have any reason to attribute any of the observed changes to human activity.
Robert Wood (08:03:00) :
“I still don’t understand why these people don’t see the obvious. If there really was a positive feedback mechanism, then we would not be here. Temperatures would have run away millions of years ago.”
But THEIR feedbacks don’t feed back! LOL
Vangel (07:52:34) :
“It looks like a cart and horse issue to me.”
The whole of AGW is a cart and horse issue.
But then:
“Global warmers predict that global warming is coming, and our emissions are to blame. They do that to keep us worried about our role in the whole thing. If we aren’t worried and guilty, we might not pay their salaries. It’s that simple.”
Kary Mullis
Winner of the 1993 Nobel Prize in Chemistry.
This may have something to do with it.
“It sounds like a very unstable system unless there are negative feedbacks to counter it”
I agree. As Warren Meyer has pointed out, what’s known as “global warming” is really two distinct hypotheses:
First, that increased levels of CO2 will result in a modest increase in global surface temperatures; and
Second, that the climate system acts to greatly amplify any increase in global surface temperatures.
There’s essentially no evidence to support the second hypothesis and the natural assumption should be that any feedbacks are negative. It’s just very unlikely that the world has been walking the razor’s edge for hundreds of millions of years just waiting for some little push to push us over the edge.
Not only that, but the earth has made it through stresses much worse than doubled or tripled CO2 levels. And yet the climate has wandered back. The reasonable and natural inference is that feedbacks are negative.
Dr Roy Spencer comments on this paper on his web-site:
New Study in Science Magazine: Proof of Positive Cloud Feedback?
Basically he thinks that this study carries the same two problems as previous cloud studies, namely (1) the regional character of the study, and (2) the issue of causation when analyzing cloud and temperature changes.
This can help to improve the simulation of clouds in climate models, which will lead to more accurate projections of future climate changes. “
This should cement the divergence between models and reality.
Fascinating…
How can one have evidence that X may cause Y?
“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.”
Also – if this theory is proven wrong, then it is the end for AGW-theory – because they state clearly that clouds shield from incoming radiation.
So if warmer oceans = more clouds, then we’re home free.
This is the last stand of AGW.
brazil84 (10:56:55) :
Exactly. The assumption that positive/destabilizing feedbacks are dominating in earths climate system is very far fetched.
I would mean that the fact that life is still present on earth is a stroke of extreme luck, considering the tremendous stress that the system must have undergone during the aeons.
Ron de Haan (05:38:46) :
Another bud naked emperor.
Repeat after me: clouds cool, clouds cool, clouds cool. clouds cool, clouds cool…
Do you get it now?
Great Ron!. All these childish discussions and playstation games are but the consequence of presumptuous new age scientists denying the real causes of changing: cycles above, impossible to change by that ultramicroscopic creature called human being. So we must be humble and hear the “music of the spheres”.
All succesful forecasters do so, contrarily to those who lately have reached such degree of foolishness as to afirm that the sun has nothing to do with climate.
These are the same who, after the french (cultural) revolution, wanted to recreate the world changing and denying eternal knowledge, using such silly things as a circle of 400 degrees.
Kendrew in “Climates of the Continents” published in 1922 describes a similar climatic region off the coast of southwest Africa in the area now called Namibia and has a similar discussion of Angola.
Search Google for / benguela current clouds / Wilfrid George Kendrew is the author and the Google result is for 1927 .
The coastal areas of South America with clouds over the Ocean and none on the land can be seen here:
http://www.eosnap.com/?tag=andes-mountains
The second image caption: “Clouds hug the coast of Chile” 6-13-2009
The photo caption with this WUWT post says: “This image shows unique cloud patterns over the Pacific Ocean of (?off) the coast of Baja California, . . .”
While areas with such cloud patterns may be of “great interest” to Clement and Burgman they are neither unique nor new. That the cloud tops show as bright white their albedo is very high. The water nearby shows up nearly black, thus, having an albedo very low. Nothing new here. To document, quantify, and include such situations in scientific studies is appropriate. Cheers, I say!
See also: John F. Hultquist (21:45:16)
When effect is confused with cause, it takes positive feedback to explain behavior. The lack of positive feedback in nature should be a clue that cause has been confused with effect.
I find it easily conceivable that clouds are BOTH a positive and a negative feedback. They could, for example, have a positive feedback short term, but stronger negative feedback long term.
I also see it likely that the cause and effect relationship between sea surface temp and clouds goes BOTH ways.
For example it could be that on a short term basis, a lack of cloud cover puts more heat into the ocean. But over a longer period, the cause-effect goes the other way, with the warm water creating more cloud cover.
This leads to some very interesting possibilities when you have movement of the warm water on a large scale such as in El Nino.
Bob Tisdale has made some intriguing comments about such things (apologies to him if I’m inappropriately extending or simplifying his argument).
Examples: This thread, Bob Tisdale (04:20:02) 7/26/09; and in Niche Modeling http://landshape.org/enm/influence-of-the-southern-oscillation-on-tropospheric-temperature/?dsq=13356696#comment-13356696
John F. Hultquist (11:42:57) :
About the clouds over south america: We, in Lima city, 12 degrees south of the equator, are covered by a thick layer of clouds, which make daylight at this hour (14:45 pm) look like 6 pm. in the afternoon. In the year 1997-98 we had no winter at all, quite differently as today, so those guys looking at their computer screens instead of looking the real sky will be wrong again.
Between 1991 and 1992 there was a marked decrease in GCR and cloud cover, which, if we consider a 6 year lag while sea water saved enough energy as to provoke 1997-1998 big El Nino. So it is important to see the heat budget of the seas.
http://www.scribd.com/doc/338170/svensmark-2007cosmoclimatology