UNITED NATIONS -- There's growing momentum for amending the Montreal Protocol, the landmark treaty credited with rescuing the earth's ozone layer, for use in a global battle against climate change.

Widely regarded as the most successful environmental treaty of all time, the Montreal Protocol is credited with eliminating 97 percent of gases used in refrigerant and cooling systems that were eating away at the atmospheric layer that protects life from harmful ultraviolet radiation.

Now, some officials are confident the treaty can be employed to fight climate change, as well, by reducing the use of hydrofluorocarbons (HFCs). The move is controversial, as HFCs do not harm ozone and are widely used as a safer substitute for chlorofluorcarbons (CFCs), with the protocol mentioning HFCs as an attractive alternative coolant.

HFC use is already loosely regulated under existing climate-change conventions. Though much less of a contributor to global warming than carbon dioxide, HFCs are known to have a heat-trapping effect thousands of times more powerful than CO2, and their climate impact is expected to grow as developing nations turn to HFCs for air conditioning and refrigeration.

For the first time, last week in Geneva, nations debated a proposed amendment tabled by the island states of Micronesia and Mauritius that would see HFCs added to the list of controlled substances. The idea proved so compelling that six other nations joined in endorsing the amendment on the final day, even though debate on the issue has barely begun.

The effort is fast shaping up as an initiative by the 36 members of the Alliance of Small Island States, or AOSIS. U.S. officials say they are also keenly interested, though they have thus far avoided an official endorsement as the Obama administration works out its overall climate change negotiating posture.

"I think we're moving very quickly toward a policy position on this, but we don't yet have one," an Obama administration official said. "There's more and more demand for air conditioning and refrigeration in the world, just generally speaking, so you're going to see a big growth in HFCs if something isn't done."

Observers also note that, through using the Montreal Protocol, the small islands pushing for an amendment have a much greater chance of quickly bridging differences between the developed and developing world than climate negotiators have. Their proposal only calls for a "phase down" of HFC use, not a blanket elimination, a policy the United States has already said publicly that it favors and one likely to be endorsed by China, India and other emerging markets where HFC use is growing rapidly.

Action via the Montreal Protocol will also likely prove much swifter than a climate treaty, as well. Under the protocol, both developed and developing nations are bound to carry out the phaseout and destruction of ozone-depleting chemicals equally, though the developing world is given a 10-year grace period to act. And changes to the protocol have historically aroused little controversy. Several revisions have already been made, the latest in 2007, when nations agreed to accelerate the phaseout of hydrochlorofluorocarbons (HCFCs).

Should U.N. climate talks fail to achieve a concrete replacement to the Kyoto Protocol by the end of the year, it is possible the Montreal treaty could be altered before a new global-warming treaty is finalized and enters into force.

"Of paramount importance is the speed at which the Montreal Protocol can negotiate, agree to, and implement a phase down a high-GWP [global warming potential] HFCs," the governments of Micronesia and Mauritius say in their proposal. "Alternative approaches will be unable to create a governance structure within the necessary time period and may not have all of the advantages that have made the Montreal Protocol successful."

But the small-island proposal as it is currently drafted cannot win the full support of other important negotiating partners, most notably the United States, meaning its proponents will have to make some major concessions.

For one thing, the draft proposal only sees advanced industrialized countries carrying out mandatory cuts in HFC use, with no similar requirements on the developing world. Every past adjustment to the Montreal Protocol had both developing and developed countries acting equally, though poorer states were afforded more time and allowed to tap into a well-used trust fund to help finance CFC- and HCFC-destruction projects.

The timing of an HFC phase down is also quicker than what has been proposed in the past. Though many industries can readily shift to alternatives of HFCs available now, others cannot, and the chemical industry has yet to devise a substitute for HFCs in some industrial uses.

Many delegates discussing the proposal at the working group meeting in Geneva last week also raised concerns that using the Montreal agreement to regulate a gas that does not erode the ozone layer may be legally impossible. The protocol is explicitly designed to guard against ozone depletion and not climate change.

But Daniel Reifsnyder, deputy assistant secretary for environment at the U.S. State Department, says international legal experts have already looked at that question and see no problems with adding HFCs to the list of ozone-depleting substances.

"Our legal folks ... are confident that this can be done under the Vienna Convention and the Montreal Protocol as it exists," Reifsnyder said. But he acknowledged, "If we were to go this direction, we might need to have interpretive decisions under both the framework convention and the Montreal Protocol to make this work."

Monetary rewards under study

Efforts to control heat-trapping HFCs though the Montreal Protocol could prove successful in the near term, giving governments one quick win that they can point to. But such a move will do little to curb the overall climate change problem.

In a report published recently in Proceedings of the National Academy of Sciences, National Oceanographic and Atmospheric Administration officials admit that HFCs released into the atmosphere contribute less than 1 percent of the heat-forcing effect of all greenhouse gases.

But governments backing an amendment insist this proportion will increase rapidly if no action is taken, with HFC stockpiles emitting "6 billion tonnes of CO2-eq [carbon dioxide-equivalent] by 2015 -- offsetting and surpassing the 5 gigatonnes CO2-eq reduction sought during the initial commitment period of the Kyoto Protocol."

Proponents also insist they have no plans to keep adding gases to the Montreal Protocol in a way that gradually transforms it into a climate treaty. But negotiators and U.N. officials are also considering other proposals that take cues from the Kyoto Protocol to reduce not only HFCs but other gases that are actually harmful to the ozone layer.

In one example, the U.N. Development Programme has suggested tapping the global carbon markets or creating a similar system whereby credits with monetary value are awarded for the destruction of ozone-eating gases.

"The ODS [ozone depleting substance] Climate Facility is a concept that's still undergoing discussions," and the details have yet to be worked out, UNDP spokesman Stansilav Saling said. "UNDP is working with the Montreal Protocol bodies to help find a good solution for financing of climate benefits, which are currently not funded by the Montreal Protocol's existing financial mechanisms."