In a week that has yielded studies on the continued rise of carbon dioxide emissions, the expected increase in global petroleum production, and the accelerated death rate of Rocky Mountain trees, a study showing progress on the hole in the ozone is a breath of fresh air.
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.
While the ozone layer appears to be on a path towards a healthy future thanks to human intervention, other human activity is pushing greenhouse gas concentrations in the atmosphere to alarming proportions. More carbon dioxide was emitted into the Earth’s atmosphere between 2012 and 2013 than in any other year since 1984, according to a report this week from the United Nation’s weather agency, the World Meteorological Organization. WMO Secretary General Michel Jarraud said in a statement that “we must reverse this trend by cutting emissions of CO2 and other greenhouse gases across the board. We are running out of time.”
Many people see a ray of hope in the Montreal Protocol when it comes to the future of climate change negotiations and the possibility of limiting emissions in time to avert devastating consequences. With a major climate march and United Nations’ climate summit planned later this month in New York City, leaders are eager to develop a meaningful post-Kyoto Protocol treaty by the end of 2015.
“The challenges that we face are still huge,” said U.N. Under-Secretary-General and UNEP Executive Director Achim Steiner in a statement released with the ozone report. “The success of the Montreal Protocol should encourage further action not only on the protection and recovery of the ozone layer but also on climate.”
The similar approaches in addressing a global atmospheric problem, caused and felt by all countries, is not the only overlap between the ozone layer and climate change. 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.
CO2, nitrous oxide, and methane are the three main long-lived greenhouse gases in the atmosphere. According to the U.N. report, the long-term future of the ozone layer, assuming HFC levels are reigned in, also depends on their concentrations.
“Overall, CO2 and methane tend to increase global ozone levels,” states the report. “By contrast, nitrous oxide, a by-product of food production, is both a powerful greenhouse gas and an ozone depleting gas, and is likely to become more important in future ozone depletion.”
The ozone layer is just starting to heal 30 years after the global effort to reduce it went into effect. In 2006 the hole reached its largest size and it is not expected to start to shrink for another decade. Changing atmospheric gas concentrations takes many years even with the most effective approaches. As greenhouse gas emissions continue to rise the goal of limiting warming to 2°C is becoming increasingly difficult without a global apparatus to facilitate the shift to a clean energy, low-carbon economy.