Ozone-friendly HFCs still pose threat

— -- Chemicals used in cooling – known as hydroflourocarbons (HFCs) – will be a far more dangerous threat to global warming in upcoming decades than previously thought, according to a study published Monday in the Proceedings of the National Academy of Sciences.

HFCs are used worldwide in refrigerators and air conditioners in buildings and in homes, cars, trucks, and trains. HFCs have been used as substitutes for ozone-depleting chemicals such as chlorofluorocarbons (CFCs) for the past 2 decades.

The study authors found that HFCs, especially from developing countries, could skyrocket from their current level of climate change contribution – about 1% of carbon dioxide – to as much as 12% of what CO2 contributes by 2050.

"HFCs are good for protecting the ozone layer, but they are not climate friendly," said David W. Fahey, study co-author and a scientist at the National Oceanic and Atmospheric Administration in Boulder, Colo.

The Montreal Protocol, a 1987 international agreement, gradually phased out the use of CFCs and other ozone-depleting substances, leading to the development of long-term replacements, such as HFCs.

Though HFCs do not deplete the ozone layer, they are potent greenhouse gases. Molecule for molecule, all HFCs are more potent warming agents than carbon dioxide and some are thousands of times more effective.