How carbon dioxide controls earth’s temperature – NASA’s Lacis: “There is no viable alternative to counteract global warming except through direct human effort to reduce the atmospheric CO2 level.”
[Via Climate Progress]
A study by GISS climate scientists recently published in the journal Science shows that atmospheric CO2 operates as a thermostat to control the temperature of Earth….
CO2 is the key atmospheric gas that exerts principal control (80% of the non-condensing GHG forcing) over the strength of the terrestrial greenhouse effect. Water vapor and clouds are fast-acting feedback effects, and as such, they are controlled by the radiative forcing supplied by the non-condensing GHGs….
There is no viable alternative to counteract global warming except through direct human effort to reduce the atmospheric CO2 level.
NASA’s Goddard Institute for Space Studies has posted three articles on their website explaining two important new studies, “Atmospheric CO2: Principal control knob governing Earth’s temperature” (subs. req’d) in Science by Andrew Lacis et al. and “The attribution of the present-day total greenhouse effect” (subs. req’d) in JGR by Gavin Schmidt et al. Together they make a terrific tutorial on the critical role human-caused CO2 plays in climate change.
A lot of nice data that all demonstrates that the key forcings for climate come from GHG such as carbon dioxide. The Science article states:
Ample physical evidence shows that carbon dioxide (CO2) is the single most important climate-relevant greenhouse gas in Earth’s atmosphere.
While water may be a stronger GHG than CO2, it cycles through the system and its condensation can remove it from the atmosphere. It is CO2 and other GHG that moderate the greenhouse effect that keeps the planet warm enough for us to live.
Without the carbon dioxide and other gases, water rapidly condenses out, freezes and completes a cycle that results in a much colder world. Without carbon dioxide, we would not be here. But too much carbon dioxide released by humans enhances this warming effect to the point that it results in increased warming.
“The bottom line is that atmospheric carbon dioxide acts as a thermostat in regulating the temperature of Earth,”
And just as with any thermostat, turning it up increases the temperature.