IMAGES: Ozone Tracker

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Science  09 Jun 2006:
Vol. 312, Issue 5779, pp. 1447
DOI: 10.1126/science.312.5779.1447e

In a few months, spring in Antarctica will mean not only that sunlight returns and the penguins get amorous. It will also herald the reappearance of the Antarctic ozone hole, a thinning of Earth's shield against ultraviolet radiation caused by humanmade chemicals. NASA's Ozone Hole Watch posts daily satellite measurements of ozone levels over the South Pole between July and December. The site also offers statistical summaries and maps of ozone readings dating back to 1979. Despite the phase-out of ozone-destroying chlorofluorocarbons, the hole remains large. In 2005, for example, its average size during the peak period of September through October was 24 million square kilometers—below 1998's record of 26 million square kilometers but still the third largest on record. Visitors can also watch animations that follow the chemical reactions that gnaw at the ozone layer.

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