> and his co-authored CaltechWater.pdf> why shouldn't there be a Ok, so I went and had a look at the pdf and found these sentences there:
"There is much indirect evidence that the water vapor feedback in models is correct, and indeed no compelling reason has emerged to doubt it. Nonetheless, it has proved difficult to articulate cleanly and convincingly from basic principles exactly why one should have confidence in this aspect of the models. If the atmosphere were saturated at all levels, understanding water vapor feedback would offer few challenges. The difficulty arises from the prevalence of highly unsaturated air in the atmosphere." That's not about clouds, which are clearly even more difficult to understand, but the pdf is about water vapour and not about clouds. I believe that we have limited knowledge about past changes in relative humidity. There are no proxies for relative moisture as far as I know. From what I've read, it's also been quite hard to prove the constant relative humidity notion by recent observation of actual, shorter term humidity trends in the atmosphere. Some related links, that people may find interesting: http://www.arm.gov/publications/proceedings/conf04/extended_abs/arking_a.pdf (clouds as thermostats) http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1398 (circulation patterns acting as feedbacks in the case of arctic sea ice) -- You received this message because you are subscribed to the Google Groups Global Change ("globalchange") newsgroup. Global Change is a public, moderated venue for discussion of science, technology, economics and policy dimensions of global environmental change. Posts will be admitted to the list if and only if any moderator finds the submission to be constructive and/or interesting, on topic, and not gratuitously rude. To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/globalchange
