Going To Zero

by Willis Eschenbach, December 12, 2018 in WUWT

I keep reading about all kinds of crazy schemes to reduce US CO2 emissions. Now, I don’t think that CO2 is the secret knob that controls the climate. I think that the earth has a host of emergent thermoregulatory mechanisms that act to keep the temperature within narrow limits (e.g. 0.6°C temperature change over the entire 20th Century). I don’t believe the claims that the modern changes in CO2 will affect the temperature.

But solely for the purposes of this post, let’s assume that the alarmists are correct. And for purposes of discussion only, let’s assume that the Earth’s temperature is free to go up and down any amount. Let’s assume that CO2 is, in fact, the secret control knob that controls the temperature of the earth. And let’s further assume that the pundits are right that the “climate sensitivity” is three degrees of warming for every doubling of CO2.

And finally, let’s assume that in 2018 the US magically stopped emitting any CO2 at all.

With all of those assumptions as prologue, here’s the question of interest.

Other things being equal, if the US stopped emitting CO2 entirely in 2018, and stayed at zero CO2 emissions indefinitely, how much cooler would that make the planet in the year 2050?

Five degrees cooler? Two degrees? One degree?



Figure 1. Historical CO2 emissions. Data from CDIAC and BP Statistical Review of World Energy