>On the way to work, I heard a report on U.S. National Public Radio that
>indicated that experts were shocked because the Arctic ozone layer was
>thinner than expected: the expected recovery of that layer had been slowed,
>where the recovery was expected because ozone-depleting chloroflourocarbons
>(CFCs) had stopped being used.
Recovery is slowing down because of abnormally low temperatures in the
stratosphere, according to William Stevens in today's NY Times:
===
The ozone layer is expected to recover eventually, possibly by the mid-21st
century.
But computer simulations of the atmosphere have suggested that lower
temperatures in the stratosphere, about 11 miles high, could increase the
rate of ozone depletion in the meantime, delaying recovery by a decade or
two.
Measurements taken by instruments carried aloft by aircraft and balloons
over the past winter have found that temperatures in the crucial layer of
the Arctic atmosphere were, indeed, among the lowest on record, and that
ozone losses of more than 60 percent occurred.
In three of the last five winters, stratospheric temperatures in the Arctic
were lower and more persistent, and covered a wider area, than at any other
time in the last 20 years, said Dr. Ross Salawitch, an ozone researcher at
the Jet Propulsion Laboratory in Pasadena, Calif., who was one of hundreds
of American and European scientists from many institutions involved in the
recent Arctic survey.
The survey's results were announced yesterday by the Pasadena laboratory
and the National Aeronautics and Space Administration's Goddard Space
Flight Center in Greenbelt, Md.
Most Arctic winters in the last decade brought unusually low ozone
coincident with an unusually cold stratosphere, according to the World
Meteorological Organization.
When the Arctic region cools, "that's bad news for the ozone," Dr.
Salawitch said, adding that the new data has "really solidified our view"
that the ozone layer is sensitive not only to ozone-destroying chemicals,
but also to temperature.
Louis Proyect
(The Marxism mailing list: http://www.marxmail.org)
