Does temperature have to rise before CO2 does?

Saturday, June 29, 2024
By John Mason

While historically Earth's temperatures have risen or fallen after its position in space slowly changed, the dominant cause of today's rapid warming is carbon dioxide emissions from human activities.

Cyclical variations in Earth’s orbit along with its axial tilt and orientation gradually affect the amount of solar energy that reaches Earth. These “Milankovitch Cycles” occur over tens of thousands of years. During a warming phase, they trigger feedback mechanisms that add additional warming.

One example is raising the temperature of the oceans, which releases carbon dioxide from the water. Thus, while CO2 increased in response to an initial warming, it also caused additional warming.

Today’s global warming is not due to Milankovitch Cycles, which are in their slow cooling phase. This time, it’s us. When we burn fossil fuels, we emit CO2 and other greenhouse gasses, which make it more difficult for heat to escape the atmosphere.

This fact brief is responsive to conversations such as this one.
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.