THE stratosphere used to be a cold, dry place. But it’s getting wetter, and no one knows why.
The concentration of water vapour in the stratosphere, which lies between 15 and 50 kilometres above the ground, has increased by half over the past 50 years. Because water absorbs infrared radiation, this damp blanket may be warming the planet.
Adam Scaife who works at the UK Met Office, in Berkshire, wondered whether El Niño might be to blame, as heating the surface of the Pacific Ocean potentially pushes warm, water-laden air into the stratosphere. His calculations, presented to the Royal Meteorological…
