LAHORE, PAKISTAN : Ozone-friendly chemicals, hydrofluorocarbons (HFCs) and perfluorocarbons (PFCs), were contributors in global warming, as both were also greenhouse gases, which has been in use for the last 20 years as a substitute for chlorofluorocarbons (CFCs) for the protection of ozone layer. Sources disclose this to Business Recorder here on Tuesday. They said that these findings were disclosed in a recently published report "Safeguarding the ozone layer and the global climate system: issues related to HFCs and PFCs", which was produced by Intergovernmental Panel on Climate Change (IPCC), in collaboration with the Technology and Economic Assessment Panel (TEAP).

After the result of two years of work by 145 experts from 35 countries, the report was finalised, they added. According to them, various solutions identified by the report could cut the global warming contribution of CFCs and their replacements in half by the year 2015.

Under the Montreal Protocol, the world's governments were phasing out CFCs, halons and other destructive chemicals and replacing them with safer alternatives. However, like CFCs themselves, some of these alternatives, such as hydrochlorofluorocarbons (HCFCs), HFCs and PFCs were also powerful greenhouse gases.

According to the report, emissions of CFCs and their replacements could be minimised by: improving the containment of chemicals to prevent leaks, evaporation and emissions of unintended by-products; reducing the amounts needed in any particular type of equipment; promoting more end-of-life recovery, recycling and destruction of substances; increasing the use of ammonia and other alternative substances with a lower or zero global warming potential; and using various emerging technologies that avoid gases that deplete ozone or contribute to climate change.

The sources said that the problem of ozone depletion arose from the wide-scale application of stable, non-flammable chemicals to refrigeration, air conditioning, foams, aerosols, fire protection and solvents starting in the middle of the last century. By the 1980s, scientists had demonstrated that these chemicals drift up into the stratosphere where they help to destroy the ozone molecules (O3) that protect life on earth from excess solar radiation, they added.

Sources said that CFCs and many of their replacements were much more powerful greenhouse gases than carbon dioxide, but emission levels were lower. The contribution that CFCs, their replacements and other ozone-depleting substances currently make to global warming was estimated to be about 10 percent of the contribution from fossil-fuel-related carbon dioxide emissions, or around five percent of humanity's total greenhouse gas emissions.

"Since virtually all ozone-depleting substances and their replacements are now used in closed systems, they are generally not emitted until years or even decades after being produced. For instance, 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 are often simply released into the atmosphere," they added.

According to them, for CFCs and HCFCs, there were no regulations under the Montreal or Kyoto Protocols to prevent such emissions. Meanwhile, the stored amounts of HFCs and HCFCs continue to increase. 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.

Consequently, reducing leaks from these sources could substantially reduce greenhouse gas emissions, benefiting both the ozone layer and the climate system. HCFCs and HFCs were estimated to currently contribute 20 percent and 15 percent respectively, of emissions from this group of chemicals.

However, by 2015 as much as 50 percent may derive from HFCs, with 40 percent from HCFCs, depending on which substitutes and technologies are used.

Source:
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