The UN meteorological agency said depletion of the ozone layer, which protects the Earth from harmful levels of ultraviolet radiation, briefly reached an unprecedented level over large swaths of the Arctic in March.
The World Meteorological Organization reported Friday that the spike stemmed from the lingering presence of man-made ozone-depleting substances in the atmosphere and very cold temperatures in the stratosphere that prevented ozone from reaching the northern region.
WMO spokeswoman Clare Nullis said conditions were “back to normal again” in April, describing the temporary depletion as “not a cause for exceptional concern.”