The California Air Resources Board (CARB) has posted a revised draft of California’s proposed Short-Lived Climate Pollutant (SLCP) Strategy. SLCPs are a category of pollutants which remain in the atmosphere for a relatively brief period, but have global warming potentials that are much higher than those of CO2. SLCPs may account for an estimated 40% of global warming, increasing the impacts of climate change.
SLCPs include black carbon (soot), methane and hydrofluorocarbons (HFCs)—the fastest-growing source of GHG emissions in California and globally—which are used as refrigerants, aerosol propellants and insulation.
Black carbon. California has already cut anthropogenic black carbon emissions by more than 90% since the 1960s, and existing measures are projected to cut mobile source emissions by 75% and total anthropogenic emissions by nearly 60% between 2000 and 2020.
These reductions have come from strong efforts to reduce on-road vehicle emissions, especially diesel particulate matter. Car and truck engines used to be the largest sources of anthropogenic black carbon emissions in California; the existing air quality policies will virtually eliminate black carbon emissions from on-road diesel engines within 10 years.
With the reduction in on-road black carbon, regulators are turning to focus on off-road mobile, fuel combustion in the industrial and power sectors, and woodstoves and fireplaces.
Although wildfire is the largest source of black carbon in California, the legislative direction and intent of SB 1383 is to include only non-forest sources of black carbon in the target. Therefore a target for forest-derived black carbon emission reductions is not included in the SLCP Strategy.
Methane. The major sources of methane in California are livestock (~30% of the state’s methane emissions), followed by landfills and oil and gas production. Methane is 72 times more efficient at trapping heat in the atmosphere than CO2, which is the most prevalent global warming gas. CO2 remains in the atmosphere for up to a century. Methane and the other SLCPs have much shorter lives, but do disproportionate damage.
New legislation (Senate Bill 1383, Lara) requires, among other things, that state agencies and affected stakeholders develop measures to reduce methane emissions from dairy and other livestock operations. The revised draft of the SLCP Strategy includes a more detailed look at how this might be accomplished through extensive collaboration with the industry and other stakeholders. The draft SLCP Strategy also takes into consideration public and stakeholder comments on other aspects of the revised strategy, as well as other legislative requirements.
The SLCP Strategy also establishes a goal of reducing fugitive methane emissions from oil and gas by 40% below current levels in 2025 and a minimum 45% in 2030, and from all other sources by 40% in 2030. This aligns with the federal government’s current goal of reducing methane emissions from oil and gas operations by 40–45% below 2012 levels by 2025.
The ARB is developing a regulation to reduce fugitive methane emissions from the oil and gas production, processing and storage sector, which will be among the most stringent such regulations in the country.
HFCs. More than three-quarters of HFC emissions in California come from the use of refrigerants in the commercial, industrial, residential, and transportation sectors.
The “Kigali Amendment” resulting from the annual Montreal Protocol Meeting of Parties in October 2016 in Kigali, Rwanda targets phasing down the production of HFCs globally. The agreement requires a reduction in the production and supply of HFCs for developed countries, including the US, as follows: 10% reduction in 2019; 40% in 2024, 70% in 2029, 80% in 2034, and 85% in 2036. Developing countries will not have to begin the phasedown until 2029, and will be allowed until 2045 to reach the 85% reductions in HFC consumption.
The ARB will sponsor a third-party assessment of the impact of the Kigali Amendment on HFC emissions and reductions in California, especially as they pertain to meeting the 40% emission reduction goal. The assessment will be completed in early 2017, and pending results of the assessment, specific HFC reduction measures may be revised accordingly.
In this SLCP Strategy, we outline SLCP emission reduction actions that provide a wide array of climate, health, and economic benefits throughout the State. The State’s organic waste should be put to beneficial use, such as for soil amendments/compost, electrical generation, transportation fuel, and pipeline-injected renewable natural gas. Organic wastes converted to biogas could supply enough renewable natural gas for about 2 million residential units. Practical solutions must be developed and implemented to overcome barriers to waste gas utilization for pipeline injection and grid interconnection. Additional data on SLCP sources must be collected in order to improve California’s SLCP emission inventory and better understand potential mitigation measures. Finally, the State should provide incentives to accelerate market transitions to cleaner technologies that foster significant system-wide solutions to cut emissions of SLCPs. Many of the sources and sectors responsible for SLCP emissions are concentrated in communities with high levels of pollution or unemployment, which could especially benefit from targeted investments to improve public health and boost economic growth.—“Revised Proposed Short-Lived Climate Pollutant Reduction Strategy”
CARB began publicly evaluating controls for SLCPs with the first AB 32 Scoping Plan in 2008. Since then Governor Brown signed SB 32 (Pavley), codifying a reductions target for statewide GHG emissions of 40 percent below 1990 emission levels by 2030. SLCP emission reductions will support achieving these targets. Also, Senate Bill 605 (Lara, 2014) requires ARB to develop a plan to reduce emissions of SLCPs, while SB 1383 requires the Board to complete and approve the plan by 1 January 2018. SB 1383 also sets targets for statewide reductions in SLCP emissions of 40% below 2013 levels by 2030 for methane and HFCs and 50% below 2013 levels by 2030 for human-caused black carbon, as well as provides specific direction for reductions from dairy and livestock operations and from landfills by diverting organic waste.
Research now shows that immediate action to cut super pollutants in California will reduce damage to forests and crops, lower background ozone and help clean the air in the state’s most polluted regions, including the Central Valley.
The SLCP Strategy is due to come before the Board for consideration in March 2017.