Ozone layer faces record 40 pct loss over Arctic:

In this July 19, 2007 file photo an iceberg is seen off Ammassalik Island in Eastern Greenland. The Arctic is a thermostat against overheating and a barometer of change, but now its own protective ozone layer that keeps out damaging ultraviolet radiation has thinned to record levels, the U.N. weather agency said Tuesday April 5, 2011. Read more: