Who thinks of the worst, if the air conditioning in the car cools or in the refrigerator keeps the food fresh. In the best case, one is reminded of the CFCs, the chlorofluorocarbons that were used in the 1980s and 1990s, as a coolant, and made the headlines – the substances cause damage to the vital ozone layer in the stratosphere, the air layer is 10 to 50 km altitude.
The Problem seemed to be solved, as in 1987, an international legally binding environmental agreements, the Montreal Protocol, the production and consumption of CFCs gradually ban. Since then, the dangerous substances in the atmosphere continuously.
Hazardous substitutes
But even success stories are not always without side effects. The industry has driven out the devil with Beelzebub. The CFCs were replaced by hydrofluorocarbons (HFCs). The spare substances that contain no chlorine that destroys the ozone molecules in the atmosphere. For this, they are powerful greenhouse gases, the escape is already in use or inappropriate disposal abundant in the air. The substances stuck today-in wardrobes worldwide in cooling systems of more than 100 million refrigerators, in air conditioners for homes and cars, spray cans and solvents.
the content of the HFCs Should continue to grow as in the past, namely by 10 to 15 percent per year, would alone cause you until the end of this century, a global warming of 0.3 to 0.5 degrees Celsius. The scientists estimate the ozone report, the international weather organization WMO and the UN environment Agency Unep have published in December of last year.
Although the lifetime of the HFCs in the atmosphere is significantly shorter than that of the greenhouse gas carbon dioxide (CO2). But: “Some of these fluorine containing gases are more than 1000 times as harmful to the climate as carbon dioxide,” says Thomas Peter, a Professor of atmospheric chemistry at the ETH Zurich.
image to enlarge
The international environmental policy has responded. Since the beginning of the year new obligations under the Montreal Protocol are in force. You require in the next thirty years, a reduction of PFCs by more than 80 percent. This addition was adopted two years ago in the Rwandan Kigali. “By the historic agreement of Kigali, combined with the Paris climate agreement might succeed, perhaps, to keep the man-made global warming below 2 degrees,” says atmospheric scientist Thomas Peter. This temperature limit is set out in the Paris agreement.
Effective environmental Treaty
To the Kigali agreement, however, came to be, it took a lot of political Persuasion. The CFC module is already in the Kyoto Protocol, the predecessor of the Treaty of the Treaty of Paris, of the six greenhouse gases whose emissions must be lowered. Because the international climate policy was blocked, however, was political pressure, to regulate the production and consumption of HFCs in the Montreal Protocol.
In the centre of the negotiations, the large emerging economies of China, India and Brazil, which are among the largest producers of PFCs were as in the climate policy. “The developing countries have a pent-up demand for the coolant, without the Kigali Convention would arise, for example, in China and India, huge stock of CFC,” says Stefan Reimann from the Swiss Federal laboratories for materials testing and research Institute.
the Montreal Protocol, which actually has the recovery of the ozone layer the objective of developing a Treaty to tackle climate change. “The agreement has so far contributed more effectively to climate protection the climate agreement,” says Michaela Hegglin, ozone researcher at the British University of Reading. Because the banned CFCs do not destroy ozone, they heat the atmosphere, so CO2 greenhouse gases. The previous reduction of ozone-depleting substances corresponds approximately to a reduction of carbon dioxide a year to 9 to 12.5 billion tons. The climate agreement of 1997, the Kyoto Protocol, led only to an annual reduction in greenhouse gases by 2.5 billion tonnes.
Changes in ozone distribution
“The Kigali agreement has also from the point of view of the ozone research of great importance, because of climate change impacts, increasingly, on the stratospheric ozone,” says Johannes Staehelin, retired Professor at ETH-Zurich Institute for atmosphere and climate in Zurich. He has been engaged since the end of the ‘ 80s with the long-term development of the ozone layer.
global warming, climate models, showed is likely to alter the global distribution of ozone in the stratosphere. The Gas is generally formed over the tropics, winds transport it then in the mid-Latitudes. This process could be accelerated by global warming.
“That may lead to a large deficit over the tropics, more ozone in our Latitudes”, ozone researcher Michaela Hegglin. On the rocks: The climate change would help in the recovery of the ozone layer in the mid-Latitudes. It could even lead to the ozone content exceeds the value of the pre-industrial time.
Hegglin thinks further: “Even if there is this theory still has many question marks. A too-high ozone value in the normal UV-radiation, which could have on the health of the people of influence would, it would, for example, is more difficult to produce enough Vitamin D.”
(editing Tamedia)
Created: 28.01.2019, 09:50 PM
