Cleaner Clouds Slow Global Heating

Cleaner clouds are now understood to be contributing to a slowdown in global heating. A study analyzing satellite data from 2008 to 2018 in the northern hemisphere found that decreasing atmospheric dust levels have led to clouds with fewer ice crystals. This is because dust particles are essential for seeding ice crystal formation in clouds.

Weakening surface winds, a consequence of climate change, have reduced the amount of dust blown into the atmosphere over the past two decades. With fewer dust particles available, clouds are becoming less icy. Since liquid droplets reflect more sunlight than ice crystals, these changes are making clouds more reflective.

This increased cloud reflectivity is a significant factor, offsetting approximately one-quarter of the warming caused by other atmospheric changes. While this is a positive development, it does not negate the overall threat of global warming, and researchers emphasize that complacency is unwarranted.