Thursday, Jul. 8, 2021
Is carbon dioxide incapable of warming the planet any more than it already has?
As CO2 accumulates in the atmosphere, trapping and re-radiating heat, Earth continues to warm. Rising CO2 acts like a blanket, reducing the amount of energy escaping into space and causing the lower atmosphere, and surface, to warm.
A long-standing misconception is that the greenhouse effect is “saturated,” suggesting that adding more CO2 will not increase the amount of energy being trapped. This view fails to recognize that the atmosphere consists of multiple layers.
Heat energy can only escape Earth from the upper atmosphere where the air is thin. CO2 adds “thickness” to upper atmospheric layers, which are not yet saturated. This lowers the rate of heat escape, much like adding more blankets to a bed.
This fact brief is responsive to conversations such as this one.
Sources
- Nature Increases in greenhouse forcing inferred from the outgoing longwave radiation spectra of the Earth in 1970 and 1997
- American Meteorological Society Measurements of the radiative surface forcing of climate
- Real Climate A saturated gassy argument
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Fact briefs are bite-sized, well-sourced explanations that offer clear "yes" or "no" answers to questions, confusions, and unsupported claims circulating online. They rely on publicly available data and documents, often from the original source. Fact briefs are written and published by Gigafact contributor publications.
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Skeptical Science is a non-profit science education organization. Our goal is to remove a roadblock to climate action by building public resilience against climate misinformation. We achieve this by publishing debunking of climate myths as well as providing resources for educators, communicators, scientists, and the general public. Skeptical Science was founded and is led by John Cook, a Senior Research Fellow with the Melbourne Centre for Behaviour Change at the University of Melbourne.
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