Quote:
Originally Posted by AstralTraveller
........Perhaps the onus is on the proponents of AGW to show that the present rate of change is unusual/unprecedented............
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The most compelling evidence for AGW ironically is not what is happening in the troposphere but in the lower stratosphere.
The lower stratosphere is ordinarily warmed through heat radiative transfer from the troposphere.
What is actually happening however is that the lower stratosphere is cooling. The mechanism is not as simple as the greenhouse effect blocking heat transfer, it involves some complicated thermodynamics but the greenhouse effect is the catalyst for cooling.
If global warming was initiated by an increase in solar flux the temperature of the lower stratosphere would be increasing.
Venus is a particularly interesting example. The surface temperature is 460C mainly due to the greenhouse effect and hotter than Mercury but the temperature of the lower stratosphere is considerably cooler than the Earths.
Regards
Steven