Scientists report the ozone layer is somewhat recovery, thanks to a drop of ozone-depleting chemicals. But they say it is unlikely to stabilize at pre-1980 levels.
Depletion of the earth's protective ozone layer is caused by the chemical action of chlorine and bromine released by man-made chlorofluorocarbons (CFCs), which are used in aerosol sprays and cooling equipment.
Ozone-depleting chemicals were banned by the 1987 Montreal Protocol which has now been ratified by 180 nations.
"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," said Dr Betsy Weatherhead, of the University of Colorado in Boulder.