September 4, 2013 11:31 am
Climate scientists agree: the climate is changing, and we’re the main cause. But while we know much about the major connections between the various factors of the climate system—the oceans, the atmosphere, the land and trees, and our effects on each of them—there is still some degree of uncertainty about exactly what will change, how much it will change and why it will do so. The biggest source of that uncertainty, says James West for Climate Desk in the video above, is clouds.
Climate Desk took a trip with NASA’s DC-8 Airborne Science Laboratory, which is working to answer a raft of cloudy questions. Clouds are a tricky thing. They can be huge, but they’re made up of billions of tiny little droplets. Their formation depends on the temperature, the pressure, the relative humidity, and often the availability of microscopic particles around which water vapor can congregate—things like bacteria or salt or ash.
Just like greenhouse gases, clouds absorb a ton of long-wave radiation (infrared radiation, or heat). Clouds act as a blanket for the Earth. But they’re also often bright white, and they reflect a lot of sunlight back into space. So, clouds are also Earth’s sunscreen. It’s trying to balance these factors—is it 50 percent sunscreen and 50 percent blanket? Or maybe 48 percent sunscreen and 52 percent blanket?—that drives the uncertainty around clouds’ role in our changing climate.
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