The Alarmists tie themselves in knots trying to explain why more CO2 = cooler stratosphere. I've tried understanding the explanation in that post. It's all highly circular and it's impossible to say whether it's correct or incorrect. Here's the chart from that post. Let's take it at face value (those are The Rules):
To cut a long story short, a pressure of 200 hPa is approx. equal to the height of the troposphere, the bit we are interested in. Below that it has warmed a bit (mainly pale green) and above that (the stratosphere) it has cooled a lot (mainly dark blue).
The ever reliable (as in 'reliably wrong') Skeptical Science explains Stratospheric Cooling and Tropospheric Warming by saying that CO2 'traps' low-energy infra red radiation emitted by the Earth's surface/oceans/clouds. The stratosphere is warmed by radiation emitted from below by the troposphere. If more infrared is 'trapped' in the troposphere, it can't warm the stratosphere.
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This of course contradicts the sophisticated 'top of troposphere' theory of Global Warming (from Science of Doom, skip down to sections 5 and 6). The TOT theory says that radiation emitted by and hence temperature at the top of the troposphere (the tropopause) are a constant. More CO2 pushes up the altitude of the tropopause.
This means that surface temperature goes up because surface temperature EQUALS temperature at the tropopause PLUS the gravity-induced lapse rate (it is nice to see an Alarmist accept that this exists and has nothing to do with Greenhouse Gases) MULTIPLIED BY the altitude of the tropopause. If that is true (I like to use their own arguments against them), then the amount of infrared reaching - and warming - the stratosphere from below is unchanged!
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So far, so bad. What is the more likely explanation?
The ozone depletion theory says - to simplify it a bit - that ozone in the stratosphere converts high-energy solar ultraviolet radiation from above to thermal energy. This appears to be undisputed. (Even the hard core Alarmists at Science of Doom accept this, while simultaneously claiming that the stratosphere is warmed from below). When ozone is depleted in the stratosphere (mainly because of CFC gases, partly because of volcanic eruptions) it soaks up less of the ultraviolet energy, and more ultraviolet energy gets down into the troposphere and heats up the ozone (and oxygen) there instead.
Game, set and match the ozone depletion theory, methinks! A back of the envelope approximation says that the fall in stratospheric temperatures will be much larger than the increase in tropospheric temperatures, which is exactly what that chart shows.
Debate Magazine
