Ozone layer declining over populated zones: study

PARIS: The ozone layer that protects life on Earth from deadly ultraviolet radiation is unexpectedly declining above the planet’s most populated regions, according to a study released Tuesday, reports AFP.

A 1987 treaty, the Montreal Protocol, banned industrial aerosols that chemically dissolved ozone in the high atmosphere, especially above Antarctica.

Nearly three decades later, the “ozone hole” over the South Pole and the upper reaches of the stratosphere are showing clear signs of recovery.

The stratophere starts about 10 kilometres (six miles) above sea level, and is about 40 kilometres thick.

At the same time, however, ozone in the lower stratosphere, 10-24 kilometres overhead, is slowly disintegrating, an international team of two dozen researchers warned.

“In tropical and middle latitudes”—home to most of humanity—“the ozone layer has not started to recover yet,” lead author William Ball, a researcher at the Swiss Federal Institute of Technology in Zurich, told AFP.

“It is, in fact, slightly worse today than 20 years ago.”

At its most depleted, around the turn of the 21st century, the ozone layer had declined by about five percent, earlier research has shown.

The new study, based on multiple satellite measurements and published in Atmospheric Chemistry and Physics, estimates that it has now diminished an additional 0.5 percent.

If confirmed, that would mean that the level of ozone depletion is “currently at its highest level ever,” Ball said by phone.

The potential for harm in lower latitudes may actually be worse than at the poles, said co-author Joanna Haigh, co-director of the Grantham Institute for Climate Change and the Environment in London.

“The decreases in ozone are less than we saw at the poles before the Montreal Protocol was enacted, but UV radiation is more intense in these regions and more people live there.”

Two possible suspects for this worrying trend stand out, the study concluded.

 

Ozone layer declining over populated zones: study

PARIS: The ozone layer that protects life on Earth from deadly ultraviolet radiation is unexpectedly declining above the planets most populated regions, according to a study released Tuesday, reports AFP. A 1987 treaty, the Montreal Protocol, banned industrial aerosols that chemically dissolved ozone in the high atmosphere, especially above Antarctica. Nearly three decades later, the ozone hole over the South Pole and the upper reaches of the stratosphere are showing clear signs of recovery. The stratophere starts about 10 kilometres (six miles) above sea level, and is about 40 kilometres thick. At the same time, however, ozone in the lower stratosphere, 10-24 kilometres overhead, is slowly disintegrating, an international team of two dozen researchers warned. In tropical and middle latitudeshome to most of humanitythe ozone layer has not started to recover yet, lead author William Ball, a researcher at the Swiss Federal Institute of Technology in Zurich, told AFP. It is, in fact, slightly worse today than 20 years ago. At its most depleted, around the turn of the 21st century, the ozone layer had declined by about five percent, earlier research has shown. The new study, based on multiple satellite measurements and published in Atmospheric Chemistry and Physics, estimates that it has now diminished an additional 0.5 percent. If confirmed, that would mean that the level of ozone depletion is currently at its highest level ever, Ball said by phone. The potential for harm in lower latitudes may actually be worse than at the poles, said co-author Joanna Haigh, co-director of the Grantham Institute for Climate Change and the Environment in London. The decreases in ozone are less than we saw at the poles before the Montreal Protocol was enacted, but UV radiation is more intense in these regions and more people live there. Two possible suspects for this worrying trend stand out, the study concluded.