Thursday, March 28, 2013

Ozone and Climate Change

New York Times columnist Gail Collins, in a column on climate change today, mentions the ozone layer, an issue often confused with climate change. Holes in the ozone layer, which is high up in the atmosphere and helps protect the earth from radiation, were discovered in the 1980s. Scientists figured out that chemicals--particularly chlorofluorocarbons (takes some practice to figure out how to spell) in refrigerants, and halons in fire extinguishers--were drifting up into the upper atmosphere and eating up the ozone layer, increasing the risk of harmful radiation from space reaching the earth. Regulations limiting the use of these chemicals were quickly passed, and the ozone layer has been on the mend ever since.

Climate change, in contrast, is mostly caused by the biproducts of combusting fossil fuels, particularly the carbon dioxide in the exhaust of cars, furnaces, power plants, etc. The carbon dioxide doesn't affect the ozone layer directly, but an internet search reveals there is an indirect link. This from NOAA: "climate change alters the atmosphere’s temperature and circulation patterns, which in turn affect the processes that deplete the ozone layer." 

In other words, despite effective efforts begun in the 1980s to restore the protective ozone layer high in the atmosphere by reducing use of CFCs and halons, the ozone layer may face additional threats, this time from climate change.