Ozone hole biggest, deepest on record

This year’s ozone hole is bigger and deeper than any other on record, NASA scientists said yesterday. From Sept. 21 to Sept. 30, the ozone hole sprawled to an average of 10.6 million square miles. That’s pretty big, alright: approximately the surface area of North America plus Argentina. In the same September time period, ozone was “virtually gone” in the atmospheric layer eight to 13 miles above the earth’s surface, says David Hofmann of the National Oceanic and Atmospheric Administration. Warmer temperatures in the stratosphere cause smaller holes o’ ozone; the colder it gets, the larger and deeper the hole gets. This year, the Antarctic experienced an unusually cold winter and spring, and the lower stratosphere was about 9 degrees chillier than average. Despite the relapse, the UV-ray-blocking ozone layer is doing better overall, thanks to human phaseout of ozone-depleting chemicals; scientists expect it to fully recover by about 2065.