GENEVA (AP) — The depletion of the ozone layer shielding Earth from damaging ultraviolet rays has reached an unprecedented low over the Arctic this spring because of harmful chemicals and a cold winter, the U.N. weather agency said Tuesday.
The Earth's fragile ozone layer in the Arctic region has suffered a loss of about 40% from the start of winter until late March, exceeding the previous seasonal loss of about 30%, the World Meteorological Organization said.........The 196-nation ozone treaty encourages industries to use replacement chemicals less damaging to ozone, the atmospheric layer that helps protect against the sun's most harmful rays.
But because these compounds have long atmospheric lifetimes, it takes decades for their concentrations to subside to pre-1980 levels as was agreed in the Montreal Protocol.
U.N. officials project the ozone layer outside the polar regions will recover to pre-1980 levels sometime between 2030 and 2040.