Record amount of ozone lost over Antarctica
Record amount of ozone lost over Antarctica
October 4, 2006
FRASCATI, Italy: The ozone hole over the South Pole has expanded to a near-record size despite a 19-year global ban on chlorofluorocarbons, the pollutant identified as being responsible for ozone depletion, the European Space Agency says.
In a statement issued on Monday by its office in Frascati, the agency said 40 million tonnes of ozone had been lost over Antarctica this year, exceeding the record 39 million tonne loss registered in 2000. "The size of this year's ozone hole is 28 million square kilometres, nearly as large as the record ozone hole extension [recorded] during 2000, and the depth of the ozone hole is rivalling the record low ozone values of 1998," the statement said.
The agency's Claus Zehner said this year's loss was caused by unusually low temperatures above Antarctica.
"Such significant ozone loss requires very low temperatures in the stratosphere, combined with sunlight," Mr Zehner said. "This year's extreme loss of ozone can be explained by the temperatures above Antarctica reaching the lowest recorded in the area since 1979."
Ozone is a protective layer found in the atmosphere that acts as a sunlight filter shielding life on Earth from harmful ultraviolet rays. Ozone loss is associated with the increased risk of skin cancer, cataracts and harm to marine life.
Chlorofluorocarbons, which contain chlorine and bromine, have been blamed for thinning the ozone layer because they attack ozone molecules, causing them to break apart.
Officially recognised by scientists in 1985, the ozone hole typically occurs during the Antarctic spring, from September to early December.
In the past decade the level of ozone in the Earth's atmosphere has fallen by about 0.3 per cent, increasing the risk of skin cancer, cataracts and harm to marine life, the agency added.
The World Meteorological Organisation said last month that the hole was nearing its record size of 29 million square kilometres set in 2000. The depth of the hole, however, was greater this year than in 2000, bringing the amount of lost ozone to 40 million tonnes on October 2.
The meteorological organisation and the UN Environment Program said in August the protective layer is likely to return to pre-1980 levels by 2049 over much of Australia, Europe, North America, Asia, Latin America and Africa. In Antarctica, they said ozone layer recovery would likely be delayed until 2065.
Man-made chlorofluorocarbons had still not vanished from the air despite being banned under the Montreal Protocol of 1987, the agency said.
http://tinyurl.com/ztdnc
October 4, 2006
FRASCATI, Italy: The ozone hole over the South Pole has expanded to a near-record size despite a 19-year global ban on chlorofluorocarbons, the pollutant identified as being responsible for ozone depletion, the European Space Agency says.
In a statement issued on Monday by its office in Frascati, the agency said 40 million tonnes of ozone had been lost over Antarctica this year, exceeding the record 39 million tonne loss registered in 2000. "The size of this year's ozone hole is 28 million square kilometres, nearly as large as the record ozone hole extension [recorded] during 2000, and the depth of the ozone hole is rivalling the record low ozone values of 1998," the statement said.
The agency's Claus Zehner said this year's loss was caused by unusually low temperatures above Antarctica.
"Such significant ozone loss requires very low temperatures in the stratosphere, combined with sunlight," Mr Zehner said. "This year's extreme loss of ozone can be explained by the temperatures above Antarctica reaching the lowest recorded in the area since 1979."
Ozone is a protective layer found in the atmosphere that acts as a sunlight filter shielding life on Earth from harmful ultraviolet rays. Ozone loss is associated with the increased risk of skin cancer, cataracts and harm to marine life.
Chlorofluorocarbons, which contain chlorine and bromine, have been blamed for thinning the ozone layer because they attack ozone molecules, causing them to break apart.
Officially recognised by scientists in 1985, the ozone hole typically occurs during the Antarctic spring, from September to early December.
In the past decade the level of ozone in the Earth's atmosphere has fallen by about 0.3 per cent, increasing the risk of skin cancer, cataracts and harm to marine life, the agency added.
The World Meteorological Organisation said last month that the hole was nearing its record size of 29 million square kilometres set in 2000. The depth of the hole, however, was greater this year than in 2000, bringing the amount of lost ozone to 40 million tonnes on October 2.
The meteorological organisation and the UN Environment Program said in August the protective layer is likely to return to pre-1980 levels by 2049 over much of Australia, Europe, North America, Asia, Latin America and Africa. In Antarctica, they said ozone layer recovery would likely be delayed until 2065.
Man-made chlorofluorocarbons had still not vanished from the air despite being banned under the Montreal Protocol of 1987, the agency said.
http://tinyurl.com/ztdnc
bin66 - 7. Okt, 01:49
