Researchers say Ozone Hole "likely to contract, may disappear"

Monday, May 22, 2006

2004 maximum ozone hole

Researchers say the ozone hole over Antarctica is likely to contract and may disappear by 2050 - as a result of a global reduction of chlorofluorocarbons (CFCs) and other ozone-depleting emissions.

The findings are based on a series of numerical simulations carried out by Eiji Akiyoshi of Tokyo's National Institute for Environmental Studies (NIES), using projected emissions of CFCs and other gases blamed for the ozone hole.

According to the Japanese report released last week, the Antarctic ozone hole is currently at its largest, but is likely to begin gradual contraction around 2020 and possibly disappear around 2050. It is believed lowered CFC emissions can cause the hole to gradually close, the NIES reported. The team's findings are in line with research by other scientists.

The scientists say CFC levels in the Earth's atmosphere have been in gradual decline since the mid-1990s, as a result of global efforts to reduce their emission.

But while Earth’s ozone layer is slowly being replenished following the international 1987 agreement banning CFCs, the Montreal Protocol, the recovery is occurring in a changing atmosphere and is unlikely to stabilize at pre-1980 levels, according to a recent University of Colorado study.

The co-author of a paper by the Danish Meteorological Institute in the May 2006 issue of Nature said: "We now have some confidence that the ozone layer is responding to the decreases in chlorine levels in the atmosphere due to the leveling off and decrease of CFCs, and most of the improvements are in agreement with what we had hoped for with the Montreal Protocol in place."

"But we are not out of the woods yet, and the ozone recovery process still faces a number of uncertainties."

Other scientists say that harmful emissions have not been lowered enough to influence the ozone hole's size. Some scientists suggest the hole won't heal until much later because old refrigerators and air-conditioners still emit CFCs.