Beyond CO2 Reductions

Clean cookstoves can reduce emissions of black carbon. 

We can slow global warming quickly by cutting emissions of four other climate pollutants: black carbon, a component of soot; methane, the main component of natural gas; lower-level ozone, a main ingredient of urban smog; and hydrofluorocarbons, or HFCs, which are used as coolants. They account for as much as 40 percent of current warming.

Unlike carbon dioxide, these pollutants are short-lived in the atmosphere. If we stop emitting them, they will disappear in a matter of weeks to a few decades. We have technologies to do this, and, in many cases, laws and institutions to support these cuts. Moreover, President Obama has the executive authority to move ahead aggressively on these pollutants, as he did last year in ordering substantial reductions in auto and truck emissions. By doing so, he may persuade other countries to follow.

Such reductions, if they occurred worldwide, would have the potential to slash the rate of global warming by half by midcentury — equivalent to wiping out the warming we have experienced over the last 50 years. These reductions would also prevent an estimated two to four million deaths from air pollution and avoid billions of dollars of crop loss annually, according to a study commissioned by the United Nations Environment Program and the World Meteorological Organization.

Reducing short-lived climate pollutants is essential for slowing the pace of climate change in the near term. We can't forget about carbon dioxide. But this strategy would provide Mr. Obama the opportunity to show leadership at home.

 [NY Times]