For the Ozone Layer, a New Look nytimes.com
[ Somewhat in contrast to the "truth" according to LindyBill, this story with associated graphics today. Freon has nothing to do with it. LindyBill says so, and I'm sure he's got indisputable bloviating punditry on call to back that up. ]
Is the ozone layer healing? Satellite observation of the hole that developed over Antarctica in the mid-1980's shows that it has split in two and has shrunk considerably since last year, making it the smallest it has been since 1988.
But federal scientists say the condition is most likely temporary and probably has nothing to do with the international ban on chemicals that deplete the ozone layer, which shields the planet from harmful solar radiation.
The hole, actually a broad area of low ozone concentrations caused by chlorofluorocarbons and other synthetic compounds that destroy ozone, forms in September and October. At its peak this year, it covered six million square miles, down from an average of nine million over the last six years.
But this is probably because of an unusual confluence of events, said scientists at NASA's Goddard Space Flight Center in Greenbelt, Md., in particular, warm temperatures around the edges of the vortex of high-altitude winds at the pole. In late September, stratospheric turbulence split the ozone gap into two lobes, a condition not seen since satellite observations of the atmosphere began in the early 1970's.
Still, the outlook is favorable. With long-lived ozone-destroying chemicals banned under the Montreal Protocol of 1987, the hole should shrink and disappear by 2050 or so, scientists say.
graphics7.nytimes.com |
