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Whatever Happened to the Hole in the Ozone Layer?

2010-05-07 05:31:08

Stuart Fox

Life's Little Mysteries Staff Writer

LiveScience.com Stuart Fox

life's Little Mysteries Staff Writer

livescience.com Thu May 6, 8:50 am ET

Three British scientists shocked the world when they revealed on May 16th, 1985

- 25 years ago - that aerosol chemicals, among other factors, had torn a hole

in the ozone layer over the South Pole. The ozone layer, which protects life on

Earth from damaging solar radiation, became an overnight sensation. And the

hole in the ozone layer became the poster-child for mankind's impact on the

planet.

Today, the ozone hole - actually a region of thinned ozone, not actually a pure

hole - doesn't make headlines like it used to. The size of the hole has

stabilized, thanks to decades of aerosol-banning legislation. But, scientists

warn, some danger still remains.

First, the good news: Since the 1989 Montreal Protocol banned the use of

ozone-depleting chemicals worldwide, the ozone hole has stopped growing.

Additionally, the ozone layer is blocking more cancer-causing radiation than

any time in a decade because its average thickness has increased, according to

a 2006 United Nations report. Atmospheric levels of ozone-depleting chemicals

have reached their lowest levels since peaking in the 1990s, and the hole has

begun to shrink.

Now the bad news: The ozone layer has also thinned over the North Pole. This

thinning is predicted to continue for the next 15 years due to weather-related

phenomena that scientists still cannot fully explain, according to the same UN

report . And, repairing the ozone hole over the South Pole will take longer

than previously expected, and won't finish until between 2060 and 2075.

Scientists now understand that the size of the ozone hole varies dramatically

from year to year, which complicates attempts to accurately predict the hole's

future size.

Interestingly, recent studies have shown that the size of the ozone hole

affects the global temperature. Closing the ozone hole actually speeds up the

melting of the polar ice caps, according to a 2009 study from Scientific

Committee on Antarctic Research.

So even though environmentally friendly laws have successfully reversed the

trend of ozone depletion, the lingering effects of aerosol use, and the link

between the ozone hole and global warming, virtually ensure that this problem

will persist until the end of the century.