Jim D
Let me address the points in your last two comments.
To your statement:
the instantaneous or transient response are much different from the final equilibrium response, which you realized is different and a long way in the future, but can’t seem to distinguish from the immediate response. As I said, the ocean warms more slowly, which should mean the RH won’t stay constant because if it gets warmer, but the water vapor stays the same, the RH goes down. I am surprised I have to explain this to you twice because it is quite basic, and I think most of the others reading this would have understood it the first time I mentioned it above.
You keep talking about climate “equilibrium”. This is a theoretical construct. Climate is never in “equilibrium”, locally, diurnally, seasonally, regionally or globally. It is always changing.
The long-term NOAA record since 1948 shows no increase in WV content with warming.
Paltridge et al. 2009 took a portion of this record starting in 1973, and also showed that WV increase did not match maintaining a constant RH with warming.
Independent observations by Minschwaner & Dessler 2004 showed that WV increase did not match maintaining a constant RH with warming.
IPCC states in AR4 WGI Ch.8, p.635:
New evidence from both observations and models has reinforced the conventional view of a roughly unchanged RH response to warming.
The empirical evidence cited above shows that this is not the case. Furthermore, there are lots of model studies, but no empirical data of which I am aware that show that WV increases with warming to maintain constant RH, as assumed by the IPCC models.
Regarding clouds you ask:
how do you explain the 90′s when it got warmer and clouds decreased? If you say that it got warmer because the clouds decreased (spontaneously, GCRs, or whatever), then why didn’t your negative feedback kick in and make it colder again?
We have gone through this once already.
Pallé et al. 2005 showed that from the 1980s to around 2000 low cloud cover decreased, decreasing Earth’s albedo and allowing more incoming SW radiation to reach the Earth’s surface, thereby causing warming.
This trend reversed itself around 2000, and low cloud cover increased again, increasing Earth’s albedo and blocking more incoming SW radiation from reaching the Earth’s surface, thereby causing cooling.
Whether or not the increased cloud cover after 2000 was a result of a “negative cloud feedback” (as observed over the tropics over shorter time periods by Spencer & Braswell 2007), or whether it was the result of another not yet understood natural mechanism, is a moot point.
At appears from the empirical evidence cited, that IPCC is on weak ground concerning its model predictions of strongly positive net cloud feedback and WV feedback based on maintaining constant RH with warming. And that was my point.
Max