Following on that comes research published last Friday in the journal Sciencethat suggests warmer waters in the northeast Pacific ocean have thinned low-level clouds, thus allowing more direct sunlight to hit the water causing a positive feedback loop that accelerates warming oceans - warmer water thins clouds, more sunlight contacts the water further warming the oceans, thinning clouds even more, letting more sunlight reach the water, and so on into a growing cycle of ocean warming.
The study, conducted by researchers at the University of Miami and the Scripps Institute of Oceanography, represent one the first reliable analysis linking cloud formations to climate change.
While the research suggests an amplifying link between cloud behavior and global warming, the data falls short of proving it. Even if the exact relationship between climate and clouds remains unsettled, the study is an important step in understanding that relationship.
I think it's an important piece of work," said NASA's Anthony Del Genio, a climate scientist with the Goddard Institute for Space Studies. "It's the second time we've documented changes in clouds in response to meteorological variations in climate."
The researchers examined records of cloud cover gathered from ships traveling in a region of the subtropics from the coast of Mexico to Hawaii between 1952 and 2007, and compared that with data collected from approximately 25 years of satellite observations. What they found was that clouds thinned in warmer conditions, a finding that lead researcher Amy Clement, a climatologist for the University of Miami, characterized as "almost shocking."
When Clement and her colleagues compared their observations with projections from climate models, they could only find one model that reproduced how the clouds behave in the real world - that being one from the UK's Hadley Centre for Climate Prediction and Research.
We completely acknowledge that the big question is, what's the link with climate sensitivity? This is a small region we examined. How much of a contribution is it? ... How much does it matter?" Clement said, adding "The big issue is that we don't have reliable data sets that cover a long time period."
The study helps chart the course of future research as Clement and her colleagues consider the work that lay ahead to improve confidence in the data signals. To improve both quantity and quality of data, one course of action is to perform similar analysis at different ocean regions, says Clement. "All the legwork is in bringing in different data sets in order to improve confidence that the signals are real."
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