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Post by Chicago Astronomer Joe on May 28, 2006 22:36:04 GMT -6
Ozone Layer Seems To Be Recovering
NASA Marshall Space Flight Center
Huntsville AL (SPX) May 29, 2006 Think of the ozone layer as Earth's sunglasses, protecting life on the surface from the harmful glare of the Sun's strongest ultraviolet rays, which can cause skin cancer and other maladies. People were understandably alarmed, then, in the 1980s when scientists noticed that manmade chemicals in the atmosphere were destroying this layer.
Governments quickly enacted an international treaty, called the Montreal Protocol, to ban ozone-destroying gases such as CFCs then found in aerosol cans and air conditioners.
Today, almost 20 years later, reports continue of large ozone holes opening over Antarctica, allowing dangerous UV rays through to Earth's surface. Indeed, the 2005 ozone hole was one of the biggest ever, spanning 24 million sq km in area, nearly the size of North America.
Listening to this news, you might suppose that little progress has been made. You'd be wrong.
While the ozone hole over Antarctica continues to open wide, the ozone layer around the rest of the planet seems to be on the mend. For the last nine years, worldwide ozone has remained roughly constant, halting the decline first noticed in the 1980s.