Greenhouse gases from chemicals used in refrigerants and air conditioning are set to be a bigger than expected spur of climate change by 2050, scientists said.
In the worst case, use of hydrofluorocarbons could surge to cause global warming in 2050 equivalent to the impact of between 28 and 45 per cent of emissions of carbon dioxide, the main heat-trapping gas from burning fossil fuels, they said.
"HFCs present a significant threat to the world's efforts to stabilise climate emissions," said Guus Velders, the lead author at The Netherlands Environmental Assessment Agency, while referring to the findings by a team of Dutch and US-based scientists. HFCs' current heat-trapping contribution to global warming is less than one per cent of that of carbon dioxide. HFCs are used in air conditioning units, including in 80 per cent of new cars, in refrigerants and in insulation foams.
HFCs were introduced before human-caused global warming was identified as a huge problem, to replace an older generation of chemicals that were damaging the ozone layer that shields the planet from harmful ultra-violet rays.
The UN Environment Programme said the study, in yesterday's edition of the US journal Proceedings of the National Academy of Sciences, showed there were easy ways to fight global warming alongside cuts in carbon emissions.
"There are other low-hanging fruit in the climate challenge," UNEP head Achim Steiner said in a statement on HFCs. He says climate change is set to cause worsening droughts, floods, heatwaves and rising sea levels.
"By some estimates, action to freeze and then reduce this group of gases could buy the world the equivalent of a decade's worth of carbon dioxide emissions," he said.
More than 190 nations plan to agree a new climate pact in Copenhagen in December to succeed the UN's Kyoto Protocol, which regulates emissions of six greenhouse gases including carbon dioxide and HFCs.
"There are simple, market-ready solutions (to HFCs) waiting to be deployed provided adequate incentives are provided," said Kert Davies, US research director for environmental group Greenpeace.