Geneva (AFP) Sept 16, 2010
The protective ozone layer in the earth's upper atmosphere has stopped thinning and should largely be restored by mid century thanks to a ban on harmful chemicals, UN scientists said on Thursday.
The "Scientific Assessment of Ozone Depletion 2010" report said a 1987 international treaty that phased out chlorofluorocarbons (CFC) -- substances used in refrigerators, aerosol sprays and some packing foams --- had been successful.
Ozone provides a natural protective filter against harmful ultra-violet rays from the sun, which can cause sunburn, cataracts and skin cancer as well as damage vegetation.
First observations of a seasonal ozone hole appearing over the Antarctic occurred in the 1970s and the alarm was raised in the 1980s after it was found to be worsening under the onslaught of CFCs, prompting 196 countries to join the Montreal Protocol.
"The Montreal Protocol signed in 1987 to control ozone depleting substances is working, it has protected us from further ozone deplation over the past decades," said World Meteorological Organisation head of research Len Barrie.
"Global ozone, including ozone in the polar region is not longer decreasing but not yet incresing," he told journalists.
The 300 scientists who compiled the four yearly ozone assessment now expect that the ozone layer in the stratosphere will be restored to 1980 levels in 2045 to 2060, according to the report, "slightly earlier" than expected.
Although CFCs have been phased out, they accumulated and persist in the atmosphere and the effect of the curbs takes years to filter through.
The ozone hole over the South Pole, which varies in size and is closely monitored when it appears in springtime each year, is likely to persist even longer and may even be aggravated by climate change, the report said.
Scientists are still getting to grips with the complex interaction between ozone depletion and global warming, Barrie explained.
"In the Antarctic, the impact of the ozone hole and the surface climate is becoming evident," he said.
"This leads to important changes in surface temperature and wind patterns, amongst other environmental changes," Barrie added.
CFCs are classified among greenhouse gases that cause global warming, so the phase out "provided substantial co-benefits by reducing climate change," the report found.
Barrie estimated that it had avoided about 10 gigatonnes of such emissions a year.
However, the ozone-friendly substances that have replaced CFCs in plastics or as refrigerants - hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs) -- are also powerful greenhouse gases.
HFCs alone are regarded as 14,000 times more powerful than carbon dioxide (CO2), which is the focus of international efforts to tackle climate change, and HFC emissions are growing by eight percent a year, according to UN agencies.
"This represents a further potential area for action within the overall climate change challenge," said UN Environment Programme chief Achim Steiner in a statement.
Share This Article With Planet Earth
All about the Ozone Layer
New technique could help ozone layer
Norwich, England (UPI) Sep 3, 2010
A new way to measure atmospheric gases could track down sources of CFCs thought to be slowing the recovery of Earth's ozone layer, European researchers say. CFCs, chlorofluorocarbons, were used in refrigerants and aerosol propellants until restricted by a global treaty in 1987, but they have stayed in the air longer than many expected, the BBC reported Friday. A team of British a ... read more
Millennium Development Goals seek end to poverty, hunger|
Chile celebrates bicentennial with miners' fate in focus
UN gathers pledges for two billion dollar Pakistan appeal
Philanthropist sees China as charity superpower
Samsung takes aim at Apple's iPad, iTunes
ARTEMIS - The First Earth-Moon Libration Orbiter
Asia defies global newspaper meltdown
E-readers yet to win mass market in China
Global Fisheries Research Finds Promise And Peril
Drought shrinks Amazon River to lowest level in 47 years
Marine Scientists Call For European Marine Observatory Network
Human Impacts On The Deep Seafloor
Russia, Canada trade rival Arctic claims
Glaciers Help High-Latitude Mountains Grow Taller
Arctic sea ice shrinks to third lowest area on record
Arctic ice melting quickly, report says
NGOs call for African biodiversity centre
In hungry region, S.African maize may feed Chinese chickens
China's Sinochem asks government to back Potash bid: report
Global Project Underway To Preserve Yam Biodiversity
Karl claims two lives, dissipates over Mexico
Hurricane Igor batters Bermuda
Powerful typhoon heads for China after lashing Taiwan
Hurricane Karl menaces Mexico, Igor eyes Bermuda
Mauritanian troops battle Al-Qaeda-linked fighters in Mali
Kenya may be lifeline for new Sudan state
Termites Foretell Climate Change In Africa's Savannas
Nigeria leader replaces military, security heads: presidency
Factfile on world population growth
Roma issue could overshadow EU summit
Scientists Glimpse Dance Of Skeletons Inside Neurons
European Parliament blasts Roma expulsions
|The content herein, unless otherwise known to be public domain, are Copyright 1995-2010 - SpaceDaily. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement|