Thread by @WIRED

Clouds cover about 2/3 of our planet at any moment. But as the Earth warms, clouds become scarce. With fewer white surfaces reflecting sunlight back to space, the Earth gets even warmer. This feedback loop could cause warming to spiral out of control: 1/ wired.trib.al/fu6zXbv

New findings reported this week in the journal Nature Geoscience make the case that the effects of cloud loss are dramatic enough to explain ancient warming episodes —and to precipitate future disaster 2/ wired.trib.al/fu6zXbv

A recent simulation revealed a tipping point at which stratocumulus clouds (which have the largest cooling effect) break up. It occurs when the concentration of CO2 reaches 1,200 per million—a level we could pass in about a century. 3/ wired.trib.al/fu6zXbv

Once that tipping point is reached, Earth’s temperature soars 8 degrees Celsius, in addition to the 4 degrees of warming or more caused by the CO2 directly. 4/ wired.trib.al/fu6zXbv

For decades, clouds have been seen as the biggest source of uncertainty over how severe global warming will be—other than what society will do to reduce carbon emissions.

Kate Marvel contemplates the cloud question with models at the NASA Goddard Institute for Space Studies: 5/

In the last decade, advances in supercomputing power and new observations of actual clouds have allowed researchers to see what happens when they crank up the CO2.

This is how they found the stratocumulus tipping point. 6/ wired.trib.al/fu6zXbv

Scientists found that when the clouds disappeared, the extra heat absorbed into the ocean increased its temperature and rate of evaporation. Extrapolated to the entire globe, the loss of low clouds and rise in water vapor leads to runaway warming—the dreaded 8-degree jump. 7/

There's a long way to go before we reach 1,200 parts per million, or thereabouts. And ultimate disaster can be averted if net carbon emissions can be reduced to zero. Read more about what the future may hold here: 8/ wired.trib.al/fu6zXbv