Clouds play a role in warming the Arctic and coinciding decreases in sea ice, but it is a complicated story. Using data from three Arctic sites, scientists studied the relationships among temperature, water vapor, and how clouds insulate the Earth. They found that in polar regions, clouds don’t behave as they do elsewhere. In the Arctic, the insulating value of clouds stays the same as long as the relative humidity doesn’t vary. This stability is disrupted if relative humidity varies.