GENEVA - Governments have moved closer to curbing the use of chemicals commonly used as coolants in refrigerators, air conditioners, hair spray and other household items in what some say would be among their biggest climate decisions ever.

The obscure round of U.N. ozone treaty talks in Geneva, which few people are following, laid the groundwork this week for a possible decision in Uganda in November to halt the promotion of hydrofluorocarbons, or HFCs, which are manmade chemicals not found naturally in the environment, and are considered greenhouse gases.

The U.S., Canada and Mexico gave the talks a boost by joining the small island nations of Micronesia and Mauritius in petitioning to amend the ozone treaty known as the 1987 Montreal Protocol to drastically cut production and use of HFCs.

By 2050, scientists predict HFCs could account for 20 per cent of the world's greenhouse gases.

"It's a controversial issue that has been discussed for the second year. It's gaining support and should the parties decide on this it would be the most important (climate) decision," said Marco Gonzalez, executive secretary of the U.N.'s ozone secretariat, which administers the treaty.

The 196-nation ozone treaty has long encouraged industries to use HFCs as ozone-friendly replacement chemicals for chlorofluorocarbons, which cause a seasonal ozone "hole" to form high in the stratosphere near the South Pole.

CFCs destroy ozone, the atmospheric layer that helps protect against the sun's most harmful rays. They also trap the earth's heat, contributing to a rise in average surface temperatures.

HFCs decompose faster than CFCs, because they contain hydrogen. But, like CFCs, they are considered potent greenhouse gases that harm the climate -- up to 10,000 times worse than carbon dioxide emissions.

Until recently, nations had overlooked the global warming impacts of some of the replacement chemicals -- hydrochloroflourocarbons, or HCFCs, and their byproducts, HFCs -- whose use has grown because of the Montreal treaty.

Then in 2007, governments agreed to speed the freeze of production and consumption of HCFCs in 2013 to fight global warming.

"If the HFC amendment is adopted by the Montreal Protocol this year, it will be single biggest and by far and away most significant climate mitigation measure ever taken in history," said Samuel LaBudde, an atmospheric campaign director with the Washington-based Environmental Investigation Agency, who was attending the talks. "It could buy the world five to 10 years from an irreversible tipping point for runaway climate change."

Discussion at the Swiss talks also has focused on a request by the U.S., Canada and Mexico to have the ozone treaty assume responsibility for destroying HFC-23, a byproduct of the refrigerant HCFC-22.

A global fund run by the U.N. and World Bank powers the ozone treaty, with about $150 million spent a year to help nations comply by phasing out CFCs.

The fund has helped prompt companies to switch from CFCs to HCFCs, HFCs and other chemicals commonly used as coolants. The main beneficiaries have been companies in China, India and other developing nations.

But under the separate Kyoto climate treaty, the U.N.-administered Clean Development Mechanism also pays manufacturers in many of the same nations to incinerate HFC-23, rather than let it vent into the atmosphere.

Environmental groups say the firms are essentially being awarded billions of dollars for carbon-cutting projects that give them what LaBudde calls "a perverse incentive" to produce more HCFC-22 -- just to have more of the lucrative byproduct to destroy.

The firms are paid based on their equivalence to carbon emissions, so for chemicals as much 10,000 times as powerful as carbon dioxide the prices go through the roof, to as much as $100,000 for every ton of HFC-23 destroyed.

"They pay the companies so much to capture and incinerate these gases ... that the byproduct is so valuable that it's become a reason for a lot of the manufacturing," he said Friday.

Another problem, he said, is that some HCFC-22 plants are not covered by the CDM, so those byproduct HFC-23 emissions go into the atmosphere.

The North American proposal to have the ozone treaty take over responsibility for destroying HFC-23 emissions from plants not covered under the CDM could be decided later this year in Uganda, or more likely next year.