Carbon dioxide — from burning fossil fuels — plays the largest role in pushing up global temperatures, climate scientists say. But methane, soot and hydrofluorocarbons also contribute to global warming. Combined, those three pollutants are believed to account for 30 to 40 percent of the nearly one degree Celsius rise in global temperatures since the beginning of the 20th century.
If adopted globally, measures to reduce soot and methane emissions could slow global warming by about a half a degree Celsius by 2030, according to research published in January.
They can have a quick effect on global warming because these gases do not last in the atmosphere as long as carbon dioxide does.
“The science is quite clear that the only way to slow warming in the near term . . . is to reduce emissions of these so-called short-lived climate forcers,” said Erika Rosenthal of the advocacy group Earthjustice.
The new program, called the Climate and Clean Air Coalition to Reduce Short-Lived Climate Pollutants, will not set targets for reductions in pollutants. Rather, it will fund education projects and joint public-private efforts to reduce emissions, said three people briefed on the announcement. They said the new program is likely to encourage nations to reduce diesel exhaust, stem the burning of agricultural waste, and capture methane from landfills, coal mines and natural gas wells, among other policies.
While most of these policies are expected to pay for themselves in the long run, each requires some upfront investment, said Johan Kuylenstierna, scientific coordinator of two U.N. reports on the benefits of reducing methane and soot.
Getting governments and industry to pay those costs is “the big challenge,” he said.
A growing body of scientific work shows that reducing emissions of soot comes with a big side benefit: Millions of lives can be saved by reducing the incidence of lung disease.
Lena Ek, Sweden’s minister of the environment, said she has “very high hopes” that the program will reduce global warming and improve global health, especially for women and children in developing nations who rely on wood-burning stoves for cooking.
Ek said several additional countries are poised to join the coalition, which will hold its first meeting April 23 in Stockholm.
While describing the program as modest, advocates of slowing greenhouse gas emissions hailed the partnership as an important step.
“It shows there are multiple strategies for addressing different pieces of climate change,” said Durwood Zaelke, president of the Institute for Governance and Sustainable Development.
Brooks Yeager of the advocacy group Clean Air Cool Planet called it a “fast-action program.” He added, “It’s just a start. It needs to get bigger.”
Paul Bledsoe of the Bipartisan Policy Center noted that, in the United States, efforts to reduce methane and soot are far less politicized than efforts to reduce carbon dioxide. Even one of the most vehement congressional opponents of limiting carbon dioxide emissions, Sen. James M. Inhofe (R-Okla.), supports cutting soot emissions.
Said Bledsoe: “This isn’t a panacea, but it represents an opportunity for bipartisan progress and near-term results on the climate front.”