A hole five times the size of California appeared over the Arctic this spring. A new study released in Nature magazine says a complete depletion of lower-stratospheric ozone occurred in early 2011, and for the first time, it could be called a hole, akin to the ozone hole over the Antarctic.
The Antarctic ozone hole occurs every year, despite efforts to slow the release of ozone-destroying forms of chlorine, and the new hole over parts of the Canadian Arctic let in harmful ultraviolet radiation over parts of northern Europe, Russia and Canada.
The Nature report states:
Chemical ozone destruction over the Arctic in early 2011 was — for the first time in the observational record — comparable to that in the Antarctic ozone hole.
The discovery of the hole comes as the Canadian government mulls a decision to cut its ozone monitoring network, the National Post reports.
The Arctic hole is not as deep as the Antarctic, and the hole likely was a result of chlorine-based pollutants in the stratosphere coupled with an extreme cold wave in the region, according to the Nature report. Scientists are unsure if the results will repeat next year.