Yesterday, I wrote about the announcement, little noticed at the time, that G8 leaders had agreed to join the Climate and Clean Air Coalition to Reduce Short-lived Climate Pollutants during their May Camp David summit. The coalition is a U.S.-led effort to combat emissions of black carbon, methane, and hydrofluorocarbons (HFCs).
A few days after G8 leaders left Camp David for the NATO summit in Chicago, the California Air Resources Board (CARB) hosted a seminar where researchers presented recent findings on the regional and global impact of short-lived climate pollutants.
James Goldstene, the Executive Officer at CARB, set the scene (PDF). He presented statistics illustrating the divergent pathways of short-lived climate pollutants – largely on the decline in developed countries, but rising sharply in emerging economies and the developing world.
In California, for instance, CO2 accounts for a much bigger share of total greenhouse gas (GHG) emissions (76%) than the global average (56%). Conversely, short-lived climate pollutants generally claim a smaller share of the GHG profile in California (black carbon, 12%; methane, 6%; HFCs, 3%) than they do globally (black carbon, 23%; methane 13%; HFCs, 1%).
Regulators have waged a decades-long campaign against poor air quality in California, and emissions of black carbon, in particular, have fallen dramatically. Diesel engine controls, aggressive fuel efficiency standards for new cars, and burning restrictions have delivered impressive results.
Goldstene displayed a chart showing that black carbon emissions from transport in California are projected to decline 80% from 1990 levels by 2020. Agricultural burning has been reduced by 90% since 1990 in the Sacramento Valley and by 80% since 2002 in the San Joaquin Valley.
CARB is intent on reducing short-lived climate pollutants further. Goldstene noted that livestock emissions, the largest source of methane in the state, are addressed by a dairy digester offset protocol approved in 2011. CARB is also considering regulation in 2013 for methane emissions from the oil and gas industry.
Alan Lloyd, President, International Council on Clean Transportation and a former CARB Chairman, urged the agency (PDF) to review its authority under AB 32 to address short-lived climate pollutants. Lloyd recommended that CARB identify statewide GHG emissions targets for 2020 that include black carbon, methane, and HFCs and update the plan for achieving maximum technologically feasible and cost-effective reductions of short-lived climate pollutants.
Erika Sasser, Senior Policy Advisor, U.S. EPA, confirmed (PDF) that the trend seen in California – a marked decline in black carbon – is occurring nationally. By 2030, she said, U.S. black carbon emissions from mobile sources are projected to decline 86% from 2005 levels thanks to emissions standards for new diesel engines and retrofit programs for trucks already on the road.
Troubling trends globally
The campaign against short-lived climate pollutants is being won in the developed world. In Asia, Latin America, and Africa, however, the situation is much grimmer. Those regions account for 75% of global black carbon emissions, said Sasser.
Marc L. Fischer, Staff Scientist, Lawrence Berkeley National Laboratory, noted (PDF) that the increase in global methane emissions had slowed dramatically for about a decade (roughly from 1996-2006). No longer. From 2006, the trend line rockets upwards. The growth is disturbing not just because methane is the third-largest global warming agent but because, as Fischer said, over a 20-year period methane has a warming potential 70 times greater than CO2.
Durwood Zaelke, President, Institute for Governance and Sustainable Development, was equally concerned (PDF) about HFCs. These fluorinated gases might only account for 1% of global GHGs, but they are the fastest growing. Even in the United States, HFC emissions are projected to double by 2020. Globally, HFCs are growing by 10% to 15% annually.
Mark Jacobson, Professor Civil and Environmental Engineering, Stanford University, warned about the impact of soot (black carbon) on the Arctic. Soot is an especially pernicious planet-warming agent. Jacobson chronicled soot’s abundant trigger points in the climate system. It absorbs solar radiation, heats clouds, evaporates water as it warms, which increases warming more, and reduces the reflectivity of snow and ice.
“Controlling soot and methane may be the only methods of preventing loss of the Arctic sea ice and a tipping point to more rapid global warming,” said Jacobson.
Note: This is the second of two posts looking at short-lived climate pollutants. In part I, published on May 30, I reported on the G8 announcement that it was joining the Climate and Clean Air Coalition to Reduce Short-lived Climate Pollutants, a U.S.-led effort to curb black carbon, methane, and HFCs emissions.
