Atmosphere Journal Entry
Atmosphere Journal Entry
Good News, Bad News On Ozone (April 19, 2010)
View of last year's ozone hole over Antarctica. The lowest ozone levels are shown in purple. NOAA.
There's good news and bad news about the ozone hole, the area over Antarctica where the ozone layer has thinned the most. The good news is the hole is starting to heal. Last fall, the hole covered about 9 million square miles (23 million sq. km) at its peak, or 2 million sq. miles (3 million sq. km) smaller than the record-sized hole observed in 2000. Now the bad news: The healing may increase warming over Antarctica. According to researchers at the University of Leeds, a larger hole is linked to stronger winds that kick up more sea salt into the atmosphere. This in turn increases cloud cover over Antarctica, reflecting sunlight and cooling the atmosphere. As ozone levels slowly get back to normal, computer models suggest more solar energy will get through.
Not everyone agrees. A NOAA researcher says other models show that rising greenhouse gas levels also increase winds over Antarctica. This increase could cancel the effects of the shrinking ozone. In addition, ozone levels over Antarctica won't recover to pre-1980 levels until at least 2060.
The ozone layer in the stratosphere helps protect us from the Sun's harmful ultraviolet (UV) rays, linked to skin cancer and cataracts. But ozone-destroying chemicals such as chlorofluorocarbons (CFCs) took a huge toll. Until they were phased out by international agreement, CFCs were widely used in products such as air-conditioners, refrigerators, and aerosol sprays.
