RIO DE JANEIRO: Scientists hope by 2005 to launch alternatives to two chemicals used as replacements for ozone-depleting chlorofluorocarbon (CFC) gases but which themselves contribute to climate change.

Hydrofluorocarbon (HFC) and perfluorocarbon (PFC) might not hurt the atmosphere’s ozone layer, but they contribute to global warming. A group of 120 scientists is studying this dilemma and hopes to find substitutes within the next two years.

CFCs are the leading culprit in the destruction of the ozone layer, and are still widely used in some countries in refrigerators and air conditioners in homes, cars, businesses and industry.

CFC replacement was stipulated in the Montreal Protocol, an international treaty signed in 1987 aimed at preserving the weakened ozone layer, which at 20 to 30 km altitude filters out the sun’s harmful ultraviolet rays.

Many countries have more than complied with the commitments made under the treaty. In some rich countries CFCs were phased out even before the 2001 deadline set for the industrialised world. Brazil hopes to achieve the mark by 2007, though developing countries have until 2010.

But the CFC substitutes (HFCs and PFCs) employed in meeting the Montreal Protocol goals also have their downside. They are greenhouse gases, meaning they contribute to trapping the sun’s energy in the atmosphere, which leads to climate change.

Both are included on the list of substances to be controlled under the Convention on Climate Change’s Kyoto Protocol of 1997, a treaty that has not yet entered into force.

One of the greatest challenges is to determine how the production and utilisation of gases, like the CFCs themselves, exacerbate both of these environmental phenomena.

To confront the challenge, the Intergovernmental Panel on Climate Change (IPCC) invited its counterpart, the Technology and Economic Assessment Panel (TEAP) to a meeting in The Hague.

There, they formed the group of 120 experts, who have until early 2005 to draw up a report evaluating the alternatives with regard to the ozone layer and climate change.

It will be an analysis of the “complete cycle of the gases, their direct and indirect effects” on climate and ozone, scientist Roberto Peixoto, a Brazilian participating in the process said.

The criteria are not linear, but rather take into account the entire system. A gas that is better as a refrigerant will not be recommended if its production requires more energy generated by greenhouse gas-producing fossil fuels, explained Peixoto, who is also assistant director of the Maua Technology Institute in Sao Paulo.

The final results of the entire research cycle could be negative.

Also in play are economic and technological factors, the interests of the industries producing the gases and the equipment involved, as well as ecological questions and national and local limitations, noted the expert.

In Europe, and in Germany in particular, it has been found that isobutane is an effective alternative for household refrigerators, but its use is limited to appliances in which a small quantity of this flammable gas does not pose a great threat, Peixoto added.

CFCs began to be used 70 years ago, but their harmful effects on the atmospheric ozone layer only became evident 30 or 40 years later.—Dawn/The InterPress News Service.