UN scientists say ozone layer depletion has stopped

Sep 16, 2010
Antarctic Ozone Hole 2010. NASA image courtesy Ozone Hole Watch.

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, 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 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 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 , the report said.

Scientists are still getting to grips with the complex interaction between and global warming, Barrie explained.

"In the Antarctic, the impact of the 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.

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User comments : 6

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vanderMerwe
2.9 / 5 (7) Sep 16, 2010
I suspect like most phenomena the ozone "hole" is a cyclical phenomena that looked like a growth trend because of the short observational time line. I wonder if we will see more envirocrazy demands that we repent and wear sackcloth and ashes the next time it decides to go down.

Next we'll be burning people in wicker men to get the spring to come. :-/
Skeptic_Heretic
2 / 5 (3) Sep 16, 2010
I suspect like most phenomena the ozone "hole" is a cyclical phenomena that looked like a growth trend because of the short observational time line. I wonder if we will see more envirocrazy demands that we repent and wear sackcloth and ashes the next time it decides to go down.

Next we'll be burning people in wicker men to get the spring to come. :-/

Well we know that ozone holes are expected, we expected them before we found them. The frightening part was how much larger they were than the hypotheses predicted. Those holes are now about where we expect them to be size wise considering the various influences that we're aware of. I'd say this particular announcement is citing a vicory for the Montreal protocol and CFC cap and trade.

The question is, is this announcement actual and sound or is it agatprop for a comming CO2 cap and trade plan. I would greatly prefer the former.
CarolinaScotsman
5 / 5 (2) Sep 16, 2010
"CFCs are classified among greenhouse gases that cause global warming, so the phase out "provided substantial co-benefits by reducing climate change,"

"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)"

So if the replacements are just as bad as CFCs were for global warming, how did replacing one for the other help reduce climate change as was stated?
Sarai_RSA
not rated yet Sep 17, 2010
@Carolina: possibly a difference in the definition of ozone depletion and greenhouse gases.

Being that this has now been proved, can we please admit that we need a similar agreement re: carbon dio2? Policies policies and beauracratic hoo-ha.
projectpeace
not rated yet Sep 17, 2010
What the scientists don't mention is that the radiative effects of the boreal forests, that protect the Earth from solar radiation, is being reduced by logging. Atmospheric balance is being thrown off in another way by a change in atmospheric aerosol production of monoterpenes.

The best remedy for this is the cultivation of industrial hemp.
kennethetucker
4 / 5 (1) Sep 18, 2010
I suspect that most idiots that 'suspect' science are a coupla 'swatches' of homo sapiens DNA short of complete

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