Earth’s Upper Atmosphere Is Cooling Fast and Scientists Finally Know Why

A Columbia-led study in Nature Geoscience explains how rising CO2 cools the stratosphere by changing its infrared absorption and emission.

The result closes a long-standing physics gap behind upper-atmosphere cooling, a well-known fingerprint of human-caused climate change.

It also sharpens climate science by showing how greenhouse gases can warm the lower atmosphere while cooling higher layers.

The work builds on decades of observations and modeling from Columbia researchers and collaborators.