Call it the darling of the global environmental movement: The Montreal Protocol is one of the rare success stories for international cooperation to clean up pollution. It could serve as a platform to phase out fluorinated gases, one of the most potent contributors to climate change.

Next week, the parties to the Montreal Protocol will convene in Bali, Indonesia, for their 23rd meeting.

"We have an opportunity to take a piece of the load off the climate change negotiations," said David Doniger, policy director of the Climate and Clean Air Program at the Natural Resources Defense Council (NRDC) -- referring to the upcoming U.N. Framework Convention on Climate Change (UNFCCC) meeting in Durban, South Africa -- "which is to do something practical on the Montreal Protocol."

The Montreal Protocol was signed in 1987 to curb the use of chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), fluorinated gases that eat away at the ozone layer, the Earth's protection against the sun's harmful ultraviolet rays.

Many of these chemicals have been replaced with hydrofluorocarbons (HFCs), fluorinated gases that are benign to the ozone layer but are extremely potent greenhouse gases -- many have a global warming potential more than 1,000 times that of carbon dioxide.

This year, the parties to the Montreal Protocol will be required to replenish the Multilateral Fund, a pot of more than $400 million to help member countries transition away from CFCs and HCFCs, used primarily in refrigeration, air conditioning, foam materials and industrial aerosols.

Environmental groups like NRDC and the Environmental Investigation Agency want this fund to support developing countries to jump straight from ozone-depleting CFCs and HCFCs to new chemicals that won't accelerate climate change. They would skip HFCs altogether.

This could help curb climate change through an established, successful venue outside of the UNFCCC, Montreal's dysfunctional cousin. The Kyoto Protocol, signed in 1997 to slow carbon dioxide emissions, is set to expire next year. Many suspect that it won't be renewed and are seeking alternatives.

The Environmental Investigation Agency estimates that phasing out HFCs would cost about $140 billion and prevent the equivalent of 11 billion metric tons of CO2 from entering the atmosphere -- about $12.7 billion per metric ton. To compare, UNFCCC's estimated future cost of abating 1 billion metric tons of CO2 equivalent is about $68 billion -- a more than fivefold increase.

A winner for ozone

Every country in the world -- except the four-month-old nation of South Sudan -- has signed the Protocol. In 2006, a World Meteorological Organization report found that the Montreal Protocol was working, and that depletion of the ozone layer will begin to reverse in the next decade.

"It's the best environmental treaty ever created," said Durwood Zaelke, president and founder of the Institute for Governance and Sustainable Development, an environmental think tank. Its members "always make decisions and move ahead at every one of its meetings."

The effectiveness of the Montreal Protocol is due to three things, said Zaelke. It built up to its success slowly but surely, first mandating a reduction of CFCs by 50 percent in 12 years, then 75 percent, then 100 percent in 10 years.

The parties implemented a policy of "common but differential responsibility": While all parties share the burden for reducing emissions of CFCs, the cost and weight of that burden varies according to economic development. Countries have a 10-year grace period to comply.

"Developed and developing countries are acting at the same time, albeit in different ways," said Doniger. "That's a hump that been hard to get over in the climate talks."

Finally, unlike greenhouse gases, which come from a variety of different sources and sectors, the gases covered by the Montreal Protocol come from a very narrow family used in a limited number of economic sectors.

For the third year, two amendments to the Montreal Protocol have been submitted at the annual conference by the United States, Canada, Mexico and Micronesia. These amendments propose that HFCs disappear at the same time as the remaining HCFCs.

But many bigger, developing countries like China, India and Brazil -- countries with rising standards of living and greater demand for refrigeration -- say these replacements are expensive and poorly established.

A loophole in the Montreal Protocol also allows countries who make HCFC-22 -- which produces a byproduct with a global warming potential more than 11,000 times that of carbon dioxide -- to gain profits from the Clean Development Mechanism, a system under the Kyoto Protocol that funds low-carbon development. These lucrative deals make a phaseout of HCFCs and HFCs much less attractive.

Cost of alternatives isn't as cool

General Motors Co. recently agreed to begin production of a relatively benign alternative, with a global warming power only four times that of carbon dioxide. This is refrigerant is expensive, said Karim Amrane, vice president of regulatory affairs and research for the Air Conditioning, Heating and Refrigeration Institute. It is also more flammable than traditional coolants, and would be illegal to use in homes or buildings.

Even at a full production capacity, refrigerants with a low global warming potential are not likely to cost less than CFCs, HCFCs or HFCs.

"They will still be more expensive than what's existing," he said. "They're not going to be cheaper, that's for sure."

Nevertheless, he said, there is a willingness in the industry to explore cleaner alternatives. The institute has undertaken a study of 30 refrigerants with relatively low global warming potential, said Amrane, for use in air conditioners, heat pumps, dehumidifiers, chillers, water heaters, ice makers and refrigerators.

Doniger does not expect any official agreements to come out of Bali, but the meeting will serve as a springboard for next year.

"While we hope to make progress, we don't expect any decision to [be made]," he said. "But we do hope that we will be allowed to process information to be gathered and detailed [for] next year."