Scientists find cloud feedbacks amplify warming more than previously thought

Clouds likely amplify warming, a new study has found. Credit: NASA

Clouds play an important role in how much the Earth warms when greenhouse gases like carbon dioxide increase. However, scientists have struggled to determine whether low-level clouds in the tropics slow down or speed up global warming, creating uncertainty in climate predictions. A new study published in Nature and funded by the Climate Program Office’s Modeling, Analysis, Predictions, and Projections (MAPP) program adds to the growing evidence that cloud feedback is very likely to amplify warming in the climate system, rather than reduce it.

The study found that the impact of clouds in the tropical Pacific and Atlantic Oceans, two areas where low clouds are especially important, is much stronger than scientists previously thought — 71% higher. It also ruled out the possibility that tropical low clouds could have a cooling effect to offset warming. These findings narrow the uncertainty around one of the biggest unknowns in climate science and enable more accurate predictions of how much warming we might expect. This work was possible thanks to new techniques that balanced conflicting data from different regions, giving clearer answers.