A new climate panic is gripping the far-Left profiteers of doom. Those few of Them who are climate scientists have made fame and fortune by telling us the world is toast unless the once-free West (though responsible for only a fifth of the world’s sins of emission) commits economic hara-kiri. The cost of placating climate Communism is already in the quadrillions.
However, They are becoming aware that Their official climate narrative is rooted in a grave error of physics – an error so elementary that it can be described here. At a vital point in Their calculation of how much warming we may cause, They forgot the Sun was shining.
By 1850, before we had any measurable impact on global temperature, direct warming from naturally occurring greenhouse gases other than water vapor was about 8 degrees absolute (Kelvin). Yet the total natural greenhouse effect by that year was 32 K – the difference between the measured global temperature of 287 K and the sunshine-only emission temperature of 255 K.
The 24 K difference between the 8 K direct and 32 K final greenhouse-gas warming up to 1850 was temperature feedback response, a knock-on, additional warming chiefly caused by more water vapor in warmer air.
Thus, They imagined, the system-gain factor – by which direct warming before feedback response is multiplied to give final warming including feedback response – was about 32 / 8, or 4. Since direct warming by doubled CO2 is little more than 1 K, they imagined that final doubled-CO2 warming – roughly equivalent to all the final warming we may cause throughout the 21st century – would be about 4 K.
That was Their mistake. They had forgotten that the water-vapor feedback (all others broadly self-cancel) must respond not only to direct warming, such as greenhouse-gas warming, but also to the surely observable fact that the Sun is shining.
After correction to take account of the feedback response to the 255 K sunshine temperature that would subsist on Earth if there were no greenhouse gases in the air at all, the system-gain factor in 1850 was not 32 / 8, or 4, as They had imagined, but (255 + 32) / (255 + 8), or 1.09.
After that strikingly simple correction to allow for the fact that very nearly all feedback response in 1850 was a response not to preindustrial greenhouse gases but to the sunshine, if the feedback regime today is as it was in 1850 we can expect not 4 K warming this century but a net-beneficial 1.1 K. That ends the “climate emergency”.