Cloud scientists plumb some cirrus mysteries


Graeme Stephens points to a slimmer icon – the amount of water in clouds. Stretch that water evenly around the planet, he explains, and it would form a wispy layer less than a tenth of a millimeter thick. Yet that sliver “is absolutely crucial for life on the planet,” says the Colorado State University atmospheric scientist. By helping to generate rain and snow, it “represents the renewable part of the fresh water cycle,” and the clouds it forms help regulate how much heat the atmosphere keeps.