Twilight zone near clouds raises warming questions
Photo by Steve0323
Climate scientists have identified what they’re describing as a “twilight zone” around clouds.
And it could complicate predictions of how fast Earth is warming. Physical scientist Lorraine Remer is at the Goddard Space Flight Center.
The twilight zone she describes happens near clouds, where aerosol particles pick up water vapor. About 30 to 60 percent of what was thought to be a cloud-free sky is actually part of this twilight zone of aerosol particles.
Lorraine Remer: If you go outside on a hazy day, you’ll see the twilight zone yourself with your own eyes. You’ll see the clouds, and you’ll see the haze. And if you look around the cloud you’ll see something sort of cloud-like, but not quite cloud-like.
Aerosols cool Earth by reflecting sunlight back to space. Remer said that aerosols from pollution counteract about 20 to 30 percent of greenhouse gas warming.
Lorraine Remer: So as we clean up our industry to produce less particles, it may have an effect we’re not expecting, which is that the fewer particles, the less sunlight goes back to space and the more global warming we could have. In terms of the particles in the vicinity of clouds, it may accentuate that effect also.
But just how much, Remer added, remains unclear.
Our thanks today to NASA: explore, discover, understand.
Our thanks to:
Lorraine Remer
Physical Scientist
NASA Goddard Space Flight Center
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