"The ozone layer that shields life from the sun's harmful rays is projected to recover from harmful chemicals by mid-century, but it will take longer over the polar regions, a United Nations study said on Thursday.

Ozone depletion -- blamed for higher ultraviolet radiation that causes skin cancers and cataracts and damages agriculture

-- will continue for decades as several key damaging substances stay in the atmosphere for a long time after emissions end.

While many cooling agents or other compounds harmful to the ozone are no longer being produced or emitted, some of their industrial replacements are greenhouses gases that contribute much more to global warming, the report said."

Stephanie Nebehay reports for Reuters September 17, 2010. [2]