An unprecedented ozone hole opened in the Arctic during 2011, researchers reported this week in the journal Nature. Holes in the Antarctic ozone layer have opened up each spring since the early 1980s, but the Arctic had only shown modest springtime ozone losses in the 5% – 30% range over the past twenty years. But this year, massive ozone destruction of 80% occurred at altitudes of 18 – 20 kilometers in the Arctic during spring, resulting in Earth’s first known case of twin ozone holes, one over each pole. During late March and portions of April, the Arctic ozone hole was positioned over heavily populated areas of Western Europe, allowing large levels of damaging ultraviolet rays to reach the surface.