Friday, September 12, 2014

The Dangerous Hole in the Ozone Layer Is Healing, and It’s Because of a Global Agreement

A view of total ozone over the Antarctic pole on Sept. 8, 2014. The purple and blue colors are where there is the least ozone, and the yellows and reds are where there is more ozone. (Credit: NASA) Click to enlarge.
According to a United Nations report published Wednesday, the ozone layer — which protects Earth’s inhabitants from the sun’s harmful ultraviolet rays — is slowly rebuilding itself.  Almost more impressive is the fact that the prevention of this harmful hole is happening because of a global treaty:  the Montreal Protocol. Signed in 1987 the Protocol’s purpose was to save the ozone layer and prevent dangerous ultraviolet radiation from reaching people.  And it is doing just that.

The U.N. study found that the ozone hole, which is above Antarctica, has stopped growing annually, and will likely recover to 1980 levels — a time before significant depletion — by mid-century.  If scientists hadn’t discovered and alerted officials to the problem and the global community hadn’t responded in prompt fashion to ban harmful chlorofluorocarbons (CFCs), chemicals normally found in air-conditioning, refrigerators and aerosol spray cans, this could be a very different story.  Without the agreement, atmospheric levels of ozone depleting substances could have increased tenfold by 2050, according to the report, which also states that the Protocol will have prevented two million cases of skin cancer annually by 2030.

After the phaseout of CFCs, hydrofluorocarbons (HFCs) became a common replacement. However it turns out HFCs can be up to a thousand times more potent of a greenhouse gas than carbon dioxide.  While CFCs are also a potent greenhouse gas, HFCs have become more of a problem as their prevalence grows.

“Hydrofluorocarbons (HFCs) do not harm the ozone layer but many of them are potent greenhouse gases,” the U.N. panel noted.  “They currently contribute about 0.5 gigatonnes of CO2-equivalent emissions per year.  These emissions are growing at a rate of about seven percent per year.  Left unabated, they can be expected to contribute very significantly to climate change in the next decades.”

While an updated global accord to address HFCs is yet to materialize, last year China and the United States reached an agreement to phase down HFC use.  The Prime Minister of India will be visiting with President Obama later this month and the issue of HFCs is likely come up in their bilateral discussions.  India is a major producer of HFCs and has been uncooperative up to this point in helping to hash out an updated global agreement.

The Dangerous Hole in the Ozone Layer Is Healing, and It’s Because of a Global Agreement

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