That's a nice set of questions. I'll try to work through them.
1. On satellite measurements, those sources are plain wrong. The satellites also show the lower atmosphere warming. Even more importantly, they show the stratosphere (upper atmosphere) cooling. That's just what you expect if the cause of the lower warming is that it's getting harder for heat to escape to higher regions. That's what's called the greenhouse effect.
2. Warming has a variety of effects on water vapor (itself a powerful greenhouse gas), clouds, ice cover. etc. Some of those effects tend to amplify the warming, some tend to make it smaller. The main difficulty in making predictions is to figure out what the net amplification factor is. Models are used, but it's even more important to use the history of the earth's temperature over the last 100 years. Since the main things driving change (changes in the sun's input, changes in greenhouse gases, changes in reflecting particles) are approximately known, one can approximately calculate how much the changes have been amplified. When scientists talk about uncertainties in exactly how much warming will be caused by a given amount of CO
2 and methane, this is where the uncertainties come from. The uncertainties in the standard international reports include these effects.
Mike W
(published on 07/04/2010)
