Massive Expansion Of Arctic Ozone Hole

Scientists report that ozone holes of similar size have opened up above the Arctic and Antarctic for the first time. Report from Reuters via the Guardian:

A huge hole that appeared in the Earth’s protective ozone layer above the Arctic in 2011 was the largest recorded in the northern hemisphere, though the sudden appearance of the hole was not due to man-made causes, scientists said in a report on Monday.
http://www.disinfo.com/2011/10/massive-expansion-of-arctic-ozone-hole/