Most of the discussion regarding the highly anticipated Senate energy
and climate change legislation, which Senators John Kerry (D-Mass.) and
Joseph Lieberman (I-Conn.) introduced last week following months of
negotiations, has focused on the bill’s provisions pertaining to
offshore oil and gas drilling, incentives for renewable
energy, and cap on carbon emissions for certain economic sectors.

Although the bill’s carbon dioxide (CO2) emissions reduction targets –
an 80 percent emissions cut by 2050 compared to 2005 levels – would
yield significant long-term climate benefits, the bill also addresses
manmade climate change in the shorter term.

A little-noticed portion of the bill concerns short-lived air
pollutants such as black carbon (otherwise known as soot) and
tropospheric ozone. These pollutants disrupt the climate on far shorter
timescales than CO2, which is the most important greenhouse gas and the
main villain in the climate change story.

Once emitted by the burning of fossil fuels, the use of solid fuel
cooking stoves or biomass burning, among other sources, black carbon
only stays aloft for days to a few weeks before being washed out of the
atmosphere by precipitation. This means that once black carbon emissions
are reduced, there would be almost immediate climate benefits.

The Kerry-Lieberman bill would direct the US EPA to use its existing
authority under the Clean Air Act to reduce black carbon emissions from
diesel engines, using devices called diesel particulate filters which
trap soot emissions before they escape via a vehicle’s tailpipe.