The U.S., Canada and four other countries have formed a coalition aimed reducing powerful but relatively short-lived pollutants in an effort to bring about near-term results in the battle against climate change.

The plan targeting methane, hydrofluorbcarbons and black carbons is viewed as a strategy that could gain more ground, and do so more swiftly, than international climate negotiations. In announcing the program, officials were careful to portray it as yet another line of attack against climate change rather than a move to abandon earlier efforts.

"This project holds a lot of promise.... But we know, of course, this effort is not the answer to the climate crisis," the London Free Press quoted U.S. Secretary of State Hillary Clinton as saying this morning. "This is meant to complement, not supplant, the other actions we are and must be taking."

The new alliance includes Sweden, Mexico, Ghana and Bangladesh. Its work is to be administered by the United Nations Environment Program with initial funding of $15 million -- $12 million to come from the U.S. over the next two years and $3 million from Canada. Canadian Environment Minister Peter Kent joined Clinton in Washington, D.C. for the State Department news conference that was attended by diplomats from other coalition countries.

So-called short-lived pollutants, such as methane, HFC and black carbon, are responsible for about one-third of global warming and remain in the atmosphere for periods ranging a few days to a few years. In contrast, carbon dioxide lingers in the atmosphere for about 100 years, and the benefits from reducing CO2 emissions are realized over a long period of time.

Quick action to reduce short-lived pollutants has the potential to reduce the global warming expected by 2050 by as much as 0.5 Celsius degrees, the Secretary of State's Office noted.

In view of climate negotiators' goal to hold a rise in global temperature to no more than 2 degrees Celsius above pre-industrial levels to avert climate disaster, "actions that could reduce, slow global warming by half a degree, that'd be a big deal," a senior administration official said in a media briefing yesterday.

Doing so could prevent millions of premature deaths from the effects of  pollution and annual damage to more than 30 million tons of crops by 2030, the Secretary of State's Office said.

The Targeted Pollutants

• Methane

With a potency 20 times that of carbon dioxide, this greenhouse gas has a 12-year lifetime in the atmosphere. Activities involving humans are estimated to be responsible for more than half the global methane emissions, according to the U.S. Environmental Protection Agency. Anthropogenic sources of methane include fossil fuel production, raising of livestock, cultivation of rice, burning of biomass and solid waste landfills.

• Black Carbon

Black carbon is what makes soot black. It comes from natural sources and human activities, resulting from incomplete combustion of fossil fuels, biofuels and biomass.

In the air, black carbon absorbs sunlight and generates heat in the atmosphere. When deposited on snow, black carbon accelerates melting because the absorption of sunlight and heat generation warm the snow, as well as the air above it and the ice beneath it.