Isn’t the global warming hysteria based on models that predict a warming of the earth a couple of °C due to increases of atmospheric CO2 from say 200 to 400 ppm?
I am very skeptical anyone can develop a model to accurately model such a complex system as the earth’s climate that can accurately predict small changes in temperature based such very small CO2 concentrations.
Doesn’t the current data show a cooling trend over the last few years?
[Isn’t the global warming hysteria based on models that predict a warming of the earth a couple of °C due to increases of atmospheric CO2 from say 200 to 400 ppm?
I am very skeptical anyone can develop a model to accurately model such a complex system as the earth’s climate that can accurately predict small changes in temperature based such very small CO2 concentrations.]
First a little background: Atmospheric gases trap heat through solar radiation hitting the surface of the Earth, being absorbed and re-radiated at longer wavelengths. This re-emitted radiation can no longer pass upwards through the atmosphere and it is trapped as excess heat. The science here is very well established and is not controversial.
Since Carbon Dioxide is more opaque to longer wavelength radiation than either Nitrogen or Oxygen, which make up about 98% of the atmosphere, it means that an increase in the amount of CO2 necessarily translates to a new equilibrium of higher atmospheric temperatures.
HOWEVER. . . . this is simply a qualitative statement that it happens. The mega trillion dollar question is to what extent this happens. According to the UN IPCC 7th ass. report the change (sensitivity) to a doubling of CO2 concentrations in the atmosphere will result in a rise of about 3C. And this is where it pays to be skeptical because if they’re right then 3C is a big increase that would have huge consequences for everyone. But if they’re wrong then they are asking the whole world to essentially turn over control of every country’s economy to a central government co they can “fix” a non-existent problem by making sure 95% if the world’s population is prohibited from using energy (the 5% in charge can use all they want).
The fact is, the process of calculating a number for climate sensitivity is filled with a lot of complexity, a great amount of uncertainty and not a few shortcuts that would normally not be allowed in any proper methodology of science.
If one does check on the methodology in detail (for which you have to read many thousands of pages plus references) it becomes apparent that the IPCC arrives at the figure of 3C by routinely assuming that the answer it gets from many of the step by step calculations along the way are on the high side of the margin of error. All of these build up to a final answer that is certainly too high. It’s telling that if they similarly erred on the low side of the margin of error in their calculations, they would get an answer that there is NO measurable change in temperature.