By Alister Doyle
OSLO (Reuters) - Cutting soot and other air pollutants could help "buy time" in the fight against climate change, a senior U.S. official said on Tuesday as seven nations joined a Washington-led plan.
Air pollution, from sources ranging from wood-fired cooking stoves in Africa to cars in Europe, may be responsible for up to six million deaths a year worldwide and is also contributing to global warming, the U.N. Environment Programme (UNEP) said.
Seven countries -- Britain, Denmark, Finland, France, Germany, Italy and Jordan -- formally joined the U.S.-led Climate and Clean Air Initiative, bringing the total of members to about 20 since the plan was launched in February.
"If we are able to do this we could really buy time in the context of the global problem to combat climate change," Jonathan Pershing, U.S. deputy special envoy for climate change, told a telephone news briefing from Paris.
Pershing said that time was "desperately" needed to slow global warming. Unlike other developed nations, the United States has not passed laws to cut greenhouse gas emissions despite proposed cuts by President Barack Obama.
Pershing said that Washington was in talks trying to attract more nations to the air pollution plan, including China and India which are the number one and three emitters of greenhouse gases respectively, with the United States in second.
The U.S.-led plan in Paris focuses on limiting soot, heat-trapping methane, ground level ozone and HFC gases. Soot, for instance, can speed the melt of Arctic ice when it lands as a dark dusting that soaks up more heat and thaws ice.
Soot can also cause respiratory diseases.
By contrast, U.N. plans for fighting climate change focus mainly on carbon dioxide, the main greenhouse gas released by burning fossil fuels that are blamed for causing more droughts, floods, wildfires and rising sea levels.
The U.N. Environment Programme, which is a partner with the U.S. initiative, said that success could reduce the projected rise in global temperatures from a build-up of greenhouse gases by 0.5 degree Celsius (0.9 Fahrenheit) by 2050.
By 2030, fast action could also prevent millions of premature deaths and avoid the annual loss of 30 million tons of crops, it said.
Pershing said that the small amount mobilized so far in pilot projects -- $13 million -- could catalyze wider change. And many projects paid for themselves in greater efficiency.
Karen Luken, of the C40 Partnership and the Clinton Climate Initiative, said that exploiting methane from trash decomposing in a landfill in Mexico City had reduced greenhouse gases and was providing energy for 35,000 homes.
"We will use that model in other places, such as Lagos."
(Editing by Mark Heinrich)