[JR: Factually untrue. Try reading this blog.]

The Clausius Clayperon equation would inply that WATER VAPOR would increase almost exponential, leading to a roughly linear increase in temperature, but NOTHING would indicate an acceleration in temperature change. Incidentally, there has been no measured increase in water vapor, which I’ll admit is pretty diffiuclt to measure accurately. In fact, measured temperatures have gone down worldwide since 2002, probably because the PDO has gone into a negative phase. When the temperature increase was detected in the late 1970s, the PDO had just shifted from a negative to a positive phase. The resulting natural increase in temperature was assumed to be part of global warming. As a result, the rate of temperatue increase caused by manmade global warming was wildly overestimated. Another problem with Hansen’s model is the assumed positive feedback caused by melting glaciers. At the end of the last ice age a lot more ice was exposed directly to the sun. Now that the icecaps are restricted to the poles, the feedback from melting ice would be a heck of a lot less than the feedback 10,000 years ago.

[JR: Try reading his paper or this blog -- many other amplifying feedbacks exist.]

http://vortex.nsstc.uah.edu/public/msu/t2lt/tltglhmam_5.2

Hansen’s estimates of 3 to 6 C are a hysterical overreaction.

Incidentally, desertification would be a net negative, not positive, feedback.
Compare temperatures in Florida with those in the desert southwest or North Africa at comparable latitudes. True, the DAYTIME temperatures are warmer in the desert, but at night those desert temperatures drop a LOT. The AVERAGE diurnal temperature is warmer in non-desert Florida-

[JR: CO2 levels are rising, and that's why The rate of temperature rise accelerates. But what is the point in arguing with somebody who so confused about desertification. If we lose soil carbon over one third of the land, that is an unmitigated climate catastrophe.]

Looking at CO2 levels (forget temp) – Pretty much every relative CO2 rise in history as resulted in mass extinction. See..
http://www.coasttocoastam.com/ timages/ page/ Extinction101506a.jpg

http://www.sciam.com/ article.cfm?articleID=00037A5D-A938-150E-A93883414B7F0000&pageNumber=1&catID=2

Now look at the recent levels of CO2….
http://www.estrellamountain.edu/ faculty/ farabee/ biobk/ CO2conc.gif

Australia’s Stern review warns of runaway global warming
“Carbon emissions are rising so fast that the world has no chance of hitting climate targets, says Australian economist”
http://www.guardian.co.uk/ environment/ 2008/ oct/ 27/ climate-change-australia

The only way that we can limit the rise to 2C is if we have a deep global depression now and throw everything in to coming out of it with zero emission technology!

Even at 2C we might have gone past major thresholds so its still fingers crossed.

Boreal forests are the largest terrestial carbon sink, and they are shifting form sink to source as they are assaulted by pine bark beetles.

There are other, less well known but significant feedbacks. For example as ice shrinks populations of krill are plummeting. Aside from being a key species in the food chain, their feeding habits also remove substantial amounts of carbon from the atmosphere. Less Krill means more carbon staying in the atmosphere.

The plain truth is, there are a lot of “minor” feedbacks such as this that cumulatively explain why our models have failed to keep up with reality.

http://westerstrand.blogspot.com/ 2008/ 09/ methane-hot-topic.html