Recent work by Goessling and colleagues has found that the changes in Earth’s energy imbalance are in large part the result of recent decreases in low cloud cover. This leads to a corresponding decrease in Earth’s albedo and allows a greater portion of incoming sunlight to be absorbed rather than reflected back into space.

Though changes in low cloud cover can explain changes in absorbed solar radiation, they aren’t really a primary cause. Cloud cover responds to other changes in the environment and can reasonably be understood as a sort of feedback or amplifier of other changes. Knowing that cloud cover changes are playing an important role in recent warming is very useful, but then requires one to determine why the cloud cover has changed.