The projected rise in global temperatures could be cut in half in coming years if world governments focused on reducing emissions of two harmful pollutants - black carbon and ground-level ozone, including methane - rather than carbon dioxide alone, according to a UN study released Wednesday.
The study, "Integrated Assessment of Black Carbon and Tropospheric Ozone," by the UN Environment Programme, shows the impact that the two short-lived pollutants have on the environment, compared with carbon dioxide, which can stay in the atmosphere for decades.
"I think what this study does that hasn't been done before is look at contributions to global warming by gases with short lifetimes," said Steve Seidel, an analyst.
Black carbon, a component of soot, is a threat to human health and is known to hasten the melting of snow. Ground-level ozone kills farm crops and also adversely affects health. Reducing the two, the study said, would improve health outcomes.
The impact from reducing short-lived pollutants such as black carbon and ground-level ozone such as methane is more immediately felt. Carbon dioxide remains in the atmosphere for years, so the effects of reducing the emissions take longer to register.
Reducing black carbon and ground-level ozone reductions would delay global warming for another 20 years, until 2070, according to the study.
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