A hole lot colder

TEMPERATURES over the Arctic hit record lows last winter, which could be bad
news for the Arctic ozone layer. From November to January, temperatures dropped
below the level at which ozone-eating stratospheric clouds begin to form, for
longer and over a larger area than had been seen before, Gloria Manney of the
Jet Propulsion Laboratory reports in Geophysical Research Letters (vol
27, p 2589). Further high-altitude cooling could lead to a northern ozone
hole.