Chicken Little may not have been far off… the sky really is falling. Or at least, the clouds are. A new study from NASA and the University of Auckland shows that over the past decade, clouds have dropped in altitude by an average of 100 feet. NASA’s Terra satellite made the discovery with an imaging system called MISR, which monitored the height and movement of Earth’s clouds from space. From 2000 to 2010, MISR found an overall lowering in these airborne collections of vapor by about 1% of their height, with fewer forming at high altitudes. No one knows why… Or even whether it’s a long-term trend. But if it is, it could have major implications for global climate change. Clouds that are lower in the atmosphere allow the Earth to cool more efficiently, dropping the surface temperature of the planet. If cloud-lowering proves to be a long-term phenomenon, it could function as a “negative feedback” mechanism, potentially slowing or counteracting global warming caused by greenhouse gases. But the timeframe of this study is too short to be conclusive, so NASA will continue to look at clouds from both sides now. And for at least the rest of this decade. For, I’m Brit Trogen.

From 2000 to 2010, NASA’s Terra satellite measured a 1% drop in cloud height. This could be a naturally occurring defense against global warming. But the study’s period is too short to know for sure. Brittany Trogen explains what's next.

Credit: Brit Trogen / / NASA

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