Earth Is Warming Faster Than Expected. A Possible Reason: Clouds

Climate scientists used dozens of tracking models to predict how much the world was likely to warm over the past two years. Most of those models fell short of the mark. New theories about the role of shrinking global cloud cover may help explain why.

Andrew Gettelman is a climatologist at the University of Colorado at Boulder. He contributed to a recent study on cloud cover. “Clouds are a huge lever on the climate system,” Gettelman told The Washington Post. “A small change in clouds could be a large change in how we warm the planet.”

The study found that, as climate change forces temperatures higher, Earth's albedo drops. Albedo is the strength of the planet’s ability to reflect the warming rays of the sun. It relies on stratocumulus clouds. They are heavy, wet clouds that sit low in the atmosphere. They are thick enough to bounce the sun’s rays back into space. When temps tick up, those clouds have trouble forming. In essence, Earth gets less "shiny."

At the same time, all the heat in our atmosphere forces cloud-creating moisture higher. There, it forms thinner cirrus clouds. These thin, wispy puffs of vapor let plenty of heat-boosting light through. Then they trap the resulting heat. That creates a feedback loop of stratocumulus-killing warmth.

Gettelman’s team published its study on clouds and warming recently in the journal Science. It found that Earth’s reduced albedo likely accounted for a 0.2-degree Celsius increase in global average temperatures since 2022. That jump matches the difference in warming between earlier climate change models and reality.

“This number of about 0.2 degrees fairly well fits this ‘missing warming,’” Goessling told the Post.

Reflect: How might changes in nature sometimes lead to big consequences?

Gif of clouds from GIPHY.