April 21, 2009

Ozone Hole Linked To Increased Antarctic Sea Ice

A hole in the ozone has resulted in a growth of Antarctic sea ice over the past 30 years, according to a report released on Tuesday.

Scientists from the British Antarctic Survey (BAS) and NASA reported the ozone hole has resulted in changing weather patterns that have caused a small rise in the amount of Antarctic sea ice, while Arctic sea ice has seen a dramatic loss.

Sea ice is a crucial part of the Earth's ecosystems. It acts as a reflector against the sun's heat, and provides a habitat for marine life.

"Although the ozone hole is in many ways holding back the effects of greenhouse gas increases on the Antarctic, this will not last, as we expect ozone levels to recover by the end of the 21st Century. By then there is likely to be around one third less Antarctic sea ice," said Professor John Turner of BAS, the lead author of the report.

Scientists used computer models and satellite images of sea ice to determine that the damaged ozone has strengthened surface winds near Antarctica and resulted in harsher storms in the South Pacific region of the Southern Ocean.

This change in weather patterns has resulted in increased cooling winds, which has lead to the rise in ice levels.

"It's the classic way that sea ice is produced. You get an offshore wind which blows the ice away from the shore and exposes open sea water which then freezes over because of the cold air," Tom Lachlan-Cope, a BAS meteorologist that co-authored the report, told Reuters.

Overall, the Antarctic sea ice has grown at a rate of about 38,610 sq miles each decade since the 1970s.

Summer sea ice rates in the North Pole dropped in 2007 to the smallest on record.

According to Reuters: "The U.N. Climate Panel says warming is caused by greenhouse gases from burning fossil fuels that will bring more floods, heatwaves, droughts and rising sea levels."

"At both poles sea ice cover is at its minimum during summer," researchers said. "However, during the winter freeze in Antarctica this ice cover expands to an area roughly twice the size of Europe."

"This new research helps us solve some of the puzzle of why sea ice is shrinking in some areas and growing in others," said Turner.

"Our results show the complexity of climate change across the Earth. While there is increasing evidence that the loss of sea ice in the Arctic has occurred due to human activity, in the Antarctic human influence through the ozone hole has had the reverse effect and resulted in more ice."

Scientists have attributed the ozone hole to the use of chemicals once used in refrigerants and hairsprays.

The study can be found in the journal Geophysical Research Letters.


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