Ozone Recovery Is Slower Than Hoped, U.N. Says

Earth’s ozone layer is finally on the mend after decades of damage, two United Nations agencies reported Friday.

But recovery has been slower than experts had hoped, the World Meteorological Organization and the U.N. Environment Program said. The ozone layer filters dangerous solar radiation.

By 2049, the protective layer will be back to pre-1980 levels over huge areas in the Northern and Southern hemispheres, the agencies said. That’s five years later than forecast in the last major scientific report, in 2002.

Over Antarctica, where ozone holes have grown over the last 30 years, recovery isn’t likely until 2065, 15 years later than previously hoped.

The new assessment is in a summary of a report by 250 scientists to be issued next year on the effects of the 1987 Montreal Protocol, which committed signatory nations to ban the use of ozone-depleting products.

“The delayed recovery is a warning that we cannot take the ozone layer for granted,” said the U.N. Environment Program’s executive director, Achim Steiner.

The ozone layer blocks harmful ultraviolet rays, and holes in it have been blamed for increased risks of skin cancer and cataracts in humans. The holes may also harm crop yields and sea life, according to researchers.

The layer’s depletion is mainly caused by the release of man-made chlorofluorocarbons, or CFCs, which are used in some aerosol sprays and cooling equipment.