Ozone Protective Gases Found to Boost Global Temperatures
GENEVA, Switzerland, April 12, 2005 (ENS) - Ozone friendly substitutes for gases that deplete the Earth's protective ozone layer are not so friendly to the global climate, a United Nations report acknowleged Monday.
Chlorofluorocarbons (CFCs) have been widely used as refrigerants, aerosol propellants, and foam blowing agents for years, but they deplete the ozone layer, causing holes to appear annually over both polar regions.
Under the Montreal Protocol, governments are phasing out CFCs, halons, and other ozone depleting chemicals and replacing them with alternatives that leave the ozone layer intact.
But like CFCs themselves, some of these alternatives, such as hydrochlorofluorocarbons (HCFCs), hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs), are powerful greenhouse gases.
“Although climate change and ozone destruction are essentially different issues, our use of certain chemicals links them together,” World Meteorological Organization Secretary-General Michel Jarraud said.
To limit their damaging effects, governments included two of the CFC alternatives in the 1992 UN Climate Change Convention and in its 1997 Kyoto Protocol, under which most developed countries must reduce their emissions from a basket of six greenhouse gases by the period 2008 – 2012.
This basket contains the alternative HFCs and PFCs.
A new report by the Intergovernmental Panel on Climate Change (IPCC), in collaboration with the Montreal Protocol's Technology and Economic Assessment Panel identifies the danger to climate stability posed by use of the ozone friendly chemicals and identifies ways to minimize their warming effect.
The result of two years of work by 145 experts from 35 countries, the report was finalized at a meeting in Addis Ababa, Ethiopia from April 6 to 8 and released Monday.
“This report demonstrates that it is in our power to maintain the Montreal Protocol’s momentum while achieving the Kyoto Protocol’s targets," said UN Environment Programme (UNEP) Executive Director Klaus Toepfer. "It also reveals that many available win-win solutions are cost-competitive when compared with options for reducing carbon dioxide and other greenhouse gases.”
“There can be no trade-offs between saving the ozone layer and minimizing climate change,” he said.
The contribution that CFCs, their replacements and other ozone depleting substances currently make to global warming is estimated to be about five percent of humanity’s total greenhouse gas emissions.
The report, entitled, "Safeguarding the ozone layer and the global climate system: issues related to hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs)," recommends minimizing the emission of these chemicals with some simple, commonsense practices.
Containment can be improved, the report says, to prevent leaks, evaporation and emissions of unintended by-products. About 65 percent of today’s total emissions from this group of chemicals still come from CFCs, mainly from existing refrigeration and air conditioning equipment. Reducing leaks from these sources could cut greenhouse gas emissions, benefiting both the ozone layer and the climate system.
Amounts of the chemicals needed in equipment can be reduced, and there should be more end-of-life recovery, recycling and destruction of HFCs and PFCs, the report suggests.
The use of ammonia and other alternative substances with a lower or zero global warming potential should be increased, and emerging technologies that avoid gases that deplete ozone or contribute to climate change should be encouraged, the report recommends.
Since virtually all ozone depleting substances and their replacements are now used in closed systems, they are not emitted until years or even decades after being produced. Large amounts of CFCs still exist in current refrigeration and air-conditioning equipment and in insulating foams, from which they can leak or evaporate. Later, when the equipment is decommissioned, they may be released into the atmosphere.
For CFCs and HCFCs, there are no regulations under the Montreal or Kyoto Protocols to prevent such emissions.
Costs to minimize emissions of CFC replacements vary depending on the type and size of a piece of equipment and the solution selected. Replacing HFCs in a household refrigerator could cost up to US$30, UNEP says, while replacing HFCs in an automobile air conditioning unit could cost from US$48 to US$180.
The costs for bigger equipment, such as supermarket systems, would be much higher.
Incinerators for destroying the HFC byproducts of HCFC manufacture, for example, could involve hundreds or thousands of dollars, although the costs for HFC incineration are lower than US$0.2 per metric ton of carbon dioxide equivalent.
But when compared to other ways of reducing greenhouse gas emissions, UNEP calls these costs "relatively low." The best solutions reduce energy use, energy costs and associated carbon dioxide emissions simultaneously.