As the World Warms, Clouds Could Disappear—Catastrophically

Natalie Wolchover | WIRED
Friday, March 8, 2019

Computer simulations are suggesting that as global temperatures rise, clouds become scarce, potentially causing warming to spiral out of control, reports Natalie Wolchover for WIRED. The findings published " in the journal Nature Geoscience make the case that the effects of cloud loss are dramatic enough to explain ancient warming episodes like the [Paleocene-Eocene Thermal Maximum] PETM—and to precipitate future disaster." Caltech climate researchers simulated stratocumulus clouds, which are the low-lying, and have the largest cooling effect on the planet. The researchers found a point at which the clouds break up and disappear when the amount of carbon dioxide in the model's atmosphere reaches 1,200 parts per million. This scenerio is possible in about a century under “business-as-usual” emissions. After this point, the model reports that Earth's temperature rises 8 oC on top of the 4 oC, which the carbon dioxide directly caused.

Once clouds go away, the simulated climate “goes over a cliff,” said Kerry Emanuel, a climate scientist at the Massachusetts Institute of Technology. A leading authority on atmospheric physics, Emanuel called the new findings “very plausible,” though, as he noted, scientists must now make an effort to independently replicate the work.

Read the full story on WIRED.

Story Image: A state-of-the-art supercomputer simulation indicates that a feedback loop between global warming and cloud loss can push Earth’s climate past a disastrous tipping point in as little as a century. (Image: Michelle Yun/Quanta Magazine, iStock)