HFCs have since been identified as greenhouse gases with global warming potentials as much as 11,700 times greater than carbon dioxide. Short-term emissions reduction targets could quickly be met, however, if vehicle air-conditioning units and other HFC-emitting technologies were required to become more efficient or to use alternative chemicals.
The three North American countries are proposing that all countries reduce their HFC consumption and production, noting that industrialized nations would need to lead the effort.
'Phasing down consumption and production of HFCs will send an important signal about the need for alternatives that pose no problem either for the ozone layer or for the climate system,' a U.S. State Department statement said.
The proposal is identical to a suggestion that the island nations of Mauritius and the Federal States of Micronesia have submitted to the United Nations Framework Convention on Climate Change. The two countries propose that the Montreal Protocol, the international agreement developed to limit ozone depleting substances, be expanded to limit HFCs.
'With the joint proposal by the United States, Canada, and Mexico, we now have the muscle to move the Montreal Protocol amendment,' said Yosiwo George, the Micronesian ambassador to the United States, in a prepared statement.
The two proposals could generate policy changes as early as November, when governments meet in Port Ghalib, Egypt, to negotiate future requirements of the Montreal Protocol. Leaders will convene again in Copenhagen, Denmark, in December to form a successor agreement to the Kyoto Protocol, which limits greenhouse gas emissions.
As demand for air conditioning and refrigeration increases globally and as countries accelerate their efforts to phase out ozone-depleting substances, producers of cooling equipment will turn increasingly to HFCs unless suitable alternatives can be identified.
Scientists from the U.S. National Oceanic and Atmospheric Administration estimated earlier this year that by 2050, HFCs could contribute as much as 12 percent of the warming effect of greenhouse gas emissions. HFCs currently contribute less than 1 percent to climate change.
The ozone layer limits harmful solar radiation from entering the lower atmosphere-serving as a crucial safety net for life on Earth. Scientists discovered in the early 1980s that industrial chemicals, mainly CFC refrigerants and solvents, were being released into the atmosphere where they triggered a chemical reaction that consumed ozone, weakening the protective ozone layer.
The Montreal Protocol is considered one of the most successful multilateral environmental agreements to date. By December, it will have effectively retired nearly 100 ozone-depleting substances. The Antarctic ozone hole, which currently spans some 24 million square kilometers, is expected to be smaller in 2009 than last year, according to the World Meteorological Organization.
The Montreal Protocol also recently became the first environmental agreement to receive worldwide participation. Timor-Leste became the final signatory when Prime Minister Xanana Gusmão announced on Wednesday that his country would ratify the protocol.
Several world leaders greeted Timo-Leste's participation, which occurred on the International Day for the Preservation of the Ozone Layer, as a positive sign for reducing ozone-depleting substances and HFCs.
'I very much welcome the news that the Montreal Protocol has finally achieved the universal recognition it deserves,' said European Union Environment Commissioner Stavros Dimas, in a statement. 'The progress the protocol has achieved in protecting both the ozone layer and the global climate shows that worldwide consensus on exceptionally important environmental issues is achievable.'