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The Climate and Clean Air Coalition to Reduce Short-Lived Climate Pollutants (CCAC) was launched by the United Nations Environment Programme (UNEP) and six countries—Bangladesh, Canada, Ghana, Mexico, Sweden and the United States—on February 16, 2012. The CCAC aims to catalyze rapid reductions in short-lived climate pollutants to protect human health, agriculture and the environment. To date more than $47 million has been pledged to the Climate and Clean Air Coalition from Canada, Denmark, the European Commission, Germany, Japan, the Netherlands, Norway, Sweden, and the United States. The program is managed out of the United Nations Environmental Programme through a Secretariat in Paris, France. ==Short-lived climate pollutants== Short-lived climate pollutants (SLCPs) are agents that have relatively short lifetime in the atmosphere – a few days to a few decades – and a warming influence on climate. The main short-lived climate pollutants are black carbon, methane and tropospheric ozone, which are the most important contributors to the human enhancement of the global greenhouse effect after CO2. These short-lived climate pollutants are also dangerous air pollutants, with various detrimental impacts on human health, agriculture and ecosystems. Other short-lived climate pollutants include some hydrofluorocarbons (HFCs). While HFCs are currently present in small quantity in the atmosphere, their contribution to climate forcing is projected to climb to as much as 19% of global CO2 emissions by 2050. 〔Integrated Assessment of Black Carbon and Tropospheric Ozone, UNEP & WMO, 2011, "()"〕 〔Climate Change 2013: The Physical Science Basis, Working Group I Contribution to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, IPCC, 2013 "()"〕 Black carbon is a major component of soot and is produced by incomplete combustion of fossil fuel and biomass. It is emitted from various sources including diesel cars and trucks, ships, residential stoves, forest fires, agricultural open burning and some industrial facilities. It has a warming impact on climate 460-1500 times stronger than CO2. Its lifetime varies from a few days to a few weeks. When deposited on ice and snow, black carbon causes both atmospheric warming and an increase of melting rate. It also influences cloud formation and impacts regional circulation and rainfall patterns. In addition, black carbon impacts human health. It is a primary component of particulate matter in air pollution that is the major environmental cause of premature death globally. 〔 Methane (CH4) is a greenhouse gas that is over 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. Methane directly influences the climate system and also has indirect impacts on human health and ecosystems, in particular through its role as a precursor of tropospheric ozone.〔 〔 〔Near-term Climate Protection and Clean Air Benefits: Actions for Controlling Short-Lived Climate Forcers, UNEP, 2011, "()"〕 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. 〔HFCs a Critical Link in Protecting Climate and the Ozone Layer, UNEP, 2011, "()"〕 Tropospheric or ground-level ozone (O3) is the ozone present in the lowest portion of the atmosphere (up to 10–15 km above the ground). It is responsible for a large part of the human enhancement of the global greenhouse effect and has a lifetime of a few days to a few weeks. It is not directly emitted but formed by sunlight-driven oxidation of other agents, called ozone precursors, in particular methane (CH4) but also carbon monoxide (CO), non-methane volatile organic compounds (NMVOCs) and nitrogen oxides (NOX). Tropospheric ozone is a harmful pollutant that has detrimental impacts on human health and plants and is responsible for important reductions in crop yields. 〔 〔 〔 〔U.S. Envtl. Prot. Agency, Integrated Science Assessment for Ozone and Related Photochemical Oxidants, EPA, 2013 600/R-10/076F〕 Potential Results of SLCP Mitigation Potential Results of SLCP Mitigation Health. Action to reduce SLCPs has the potential to achieve multiple benefits. For example, each year, more than 6 million people die prematurely from indoor and outdoor air pollution. Short-lived climate pollutants are largely to blame. Fast actions on short-lived climate pollutants, such as the widespread adoption of advanced cookstoves and clean fuels, have the potential to prevent over 2 million of premature deaths each year. 〔 〔 〔 Agriculture. Reducing methane and black carbon could also prevent major crop losses. Present day global relative yield losses due to tropospheric ozone exposure range between 7-12 percent for wheat, 6-16 percent for soybean, 3-4 percent for rice, and 3-5 percent for maize . In addition, black carbon influences the formation of clouds that have a negative effect on the photosynthesis that impacts plant growth. Rapidly reducing short-lived climate pollutants, for instance through the collection of landfill gas or the recovery of methane from coal mines, has the potential to avoid the annual loss of more than 30 million tons of crops. 〔 〔 〔 〔 Climate. Reducing SLCPs could slow down the warming expected by 2050 by about 0.5°C, almost halving projected near-term warming. SLCP reduction is likely to have enhanced climate benefits in many vulnerable regions, such as elevated snow- and ice-covered regions, and is also likely to reduce regional disruption of traditional rainfall patterns. Though HFCs currently represent a small fraction of total greenhouse gases, their warming impact is particularly strong, and their emissions are projected to increase nearly twentyfold in the next three decades if their growth is not reduced. The most commonly used HFC is HFC-134a, which is 1,430 times more damaging to the climate system then carbon dioxide. HFC emissions could offset much of the climate benefits from the Montreal Protocol. They are projected to rise to about 3.5 to 8.8 Gt CO2eq in 2050, comparable to total current annual emissions from transport, estimated at around 6-7 Gt annually. There are options available that could avoid or replace high-GWP HFCs in many sectors and also ways to reduce emissions. 〔 〔 〔 〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Climate and Clean Air Coalition to Reduce Short-Lived Climate Pollutants」の詳細全文を読む スポンサード リンク
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