CLOUDS

There has been much debate over how clouds would affect global warming. Would they slow it down or amplify it? Warmists are at the moment in a state of frabjous joy over a study which appears to show that cloud changes amplify global warming. Rather than note any of the Warmist comments, I simply reproduce below the summary from "Science" magazine which describes the study concerned:

Clouds Appear to Be Big, Bad Player in Global Warming

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.

Science 24 July 2009: Vol. 325. no. 5939, p. 376

The caution I have highlighted in red seems generally to have been be ignored. Note also that for the last 10 years there has been no warming for clouds to amplify (or not) so the question is probably moot anyway. There is considerable cloud expertise among climate skeptics so I expect that we will hear more about this in the next few days

Posted by John Ray. For a daily critique of Leftist activities, see DISSECTING LEFTISM. To keep up with attacks on free speech see TONGUE-TIED. Also, don't forget your daily roundup of pro-environment but anti-Greenie news and commentary at GREENIE WATCH . Email me (John Ray) here