Every August, the ozone hole begins to grow over Antarctica, reaching its maximum size by late September. But by the New Year, it's gone again. Russell Schnell, of NOAA's Earth System Research Laboratory, explains the weird forces behind the ozone hole's formation -- and why, in recent years, an ozone hole has capped the Arctic too.
Produced by Christopher Intagliata, Senior Producer
Produced by Jon Chang, Science Friday Intern