The following excerpt is from the U.S. State Department website:
Fact SheetOffice of the SpokespersonWashington, DC
February 16, 2012
THE PROBLEM
Pollutants that are short-lived in the atmosphere such as methane, black carbon and hydrofluorocarbons (HFCs) together account for approximately one-third of current global warming, have significant impacts on public health, the environment, and world food productivity.
THE POTENTIAL
Fast action to reduce short-lived climate pollutants can have a direct impact on global warming, with the potential to reduce the warming expected by 2050 by as much as 0.5 Celsius degrees. At the same time, by 2030, such action can prevent millions of premature deaths, while also avoiding the annual loss of more than 30 million tons of crops. Moreover, many of these benefits can be achieved at low cost and with significant energy savings.
THE RESPONSE
Secretary of State Hillary Rodham Clinton today announced the Climate and Clean Air Coalition to Reduce Short-Lived Climate Pollutants, a new global initiative to seize the opportunity of realizing concrete benefits on climate, health, food and energy resulting from reducing short-lived climate pollutants. The coalition will focus efforts on reducing black carbon, hydrofluorocarbons (HFCs), and methane. The founding coalition partners are Bangladesh, Canada, Ghana, Mexico, Sweden, and the United States, together with the UN Environment Programme.
The new coalition is the first effort to treat these pollutants together, as a collective challenge. It will catalyze new actions and highlight and bolster the work of existing efforts such as the Global Alliance for Clean Cookstoves, the Arctic Council, the Montreal Protocol, and the Global Methane Initiative (GMI). The Coalition’s work will augment, not replace, global action to reduce carbon dioxide (CO2).
The coalition will reduce short-lived climate pollutants by driving the development of national action plans and the adoption of policy priorities; building capacity among developing countries; mobilizing public and private funds for action; raising awareness globally; fostering regional and international cooperation, and; improving scientific understanding of the pollutant impacts and mitigation.
The United States is already actively engaged in efforts to reduce these pollutants on the national and international levels. Here at home, the U.S. Environment Protection Agency addresses these pollutants through robust programs that protect public health and the environment. Work on the international level is taking place through the Global Methane Initiative, the Montreal Protocol, the Arctic Council and the Global Alliance for Clean Cookstoves, which was launched by Secretary Clinton in 2010.
ABOUT SHORT-LIVED CLIMATE POLLUTANTS
The pollutants targeted by this initiative remain in the atmosphere for only a few days to a few years after they are emitted. This is very short when compared to CO2, which remains in the atmosphere for approximately a century. This “shorter” atmospheric lifetime means that actions to reduce emissions will quickly lower atmospheric concentrations of these pollutants, yielding a relatively rapid climate response. Of the pollutants that will be targeted by this initiative, methane and black carbon stand out for their significant contribution to climate change, while HFCs are a rapidly increasing climate threat.
Methane
Methane (CH4) is a greenhouse gas that is more than 20 times more potent than CO2, and has an atmospheric lifetime of about 12 years. It is produced through natural processes (i.e. the decomposition of plant and animal waste), but is also emitted from many man-made sources, including coal mines, natural gas and oil systems, and landfills.
In addition to the climate benefits, reducing methane emissions has other important public health and agricultural benefits. Reducing methane emissions can avoid the health effects and premature deaths associated with unhealthy ozone levels.
Methane also is the primary component of natural gas. Thus, capturing and utilizing methane as clean-burning natural gas can promote sustainable development and energy security.
Black Carbon
Black carbon, which is a part of a mixture called soot, is emitted from a wide variety of sources that burn but do not fully combust fossil or plant-based fuels. Common sources include diesel trucks and buses, agricultural burning, and inefficient cookstoves, among others. Of the three pollutant types, black carbon remains in the atmosphere for the shortest amount of time, depositing on the ground only days to weeks after it is emitted.
Reducing black carbon will have an important impact on air quality and public health. The World Health Organization (WHO) estimates that currently more than 3 million premature deaths each year can be attributed to the effects of urban outdoor air pollution and indoor air pollution. Fine particles, which include black carbon, contribute significantly to these adverse impacts. Widespread adoption of advanced cookstoves and clean fuels that reduce black carbon emissions, for example, has the potential to prevent millions of premature deaths.
Black carbon in the atmosphere also directly contributes to climate change by absorbing sunlight when it is emitted in the atmosphere. It also contributes once it is deposited on surfaces such as snow and ice, causing them to melt faster because of its black color. As a result, reducing black carbon is particularly important to address climate change in snow- and ice-covered regions such as the Arctic and the Himalayas.
Hydrofluorocarbons (HFCs)
HFCs are man-made greenhouse gases used in air conditioning, refrigeration, solvents, foam blowing agents, and aerosols. Many HFCs remain in the atmosphere for less than 15 years. Though they represent a small fraction of the current total greenhouse gases (less than one percent), their warming impact is particularly strong and, if left unchecked, HFCs could account for nearly 20 percent of climate pollution by 2050."
