A giant 13 mile long hole in the ozone layer was discovered last October 2011 by Canadian scientists using satellite data and reported in the journal Nature. The ozone depletion was attributed to an unexpected drop in temperature in the area which had never happened before. This in combination with man-made chlorine chemical interactions, allowed the massive hole to form. The new hole in the ozone layer is similar to one discovered previously in the Antarctic. This is believed to be the first such example of twin ozone holes on Earth. Scientists reviewing the data have determined that the new rupture in the ozone layer will allow harmful ultraviolet radiation to hit northern Canada, Europe and Russia this spring, potentially affecting future wheat crop yields.
- Arctic mystery: What killed the ozone, and will it strike again? (calgaryherald.com)
- Large Ozone Hole Observed Again in 2011 (japanfs.org)
- Ozone hole highlights need for better monitoring: scientists (canada.com)