The California Air Resources Board ("CARB") has begun implementing its Short-Lived Climate Pollutant ("SLCP") Reduction Strategy ("SLCP Strategy"), which was approved by CARB in March 2017. The SLCP Strategy outlines a range of options, including regulations, incentives, and other market-supporting activities, to accelerate SLCP emission reduction measures in California, with a focus on anthropogenic black carbon (soot), methane, and hydrofluorocarbons ("HFCs").

CARB's SLCP Strategy was developed pursuant to SB 605 (2016) and SB 1383 (2016). SB 605 required CARB to develop a comprehensive strategy to reduce SLCP emissions in California, including completing an inventory of SLCPs in the state, identifying existing and new control measures to reduce emissions, and prioritizing the development of new measures for SLCPs that offer cobenefits. SB 1383 required CARB to approve and begin implementing the SLCP Strategy by January 1, 2018, and set targets for statewide reductions in SLCP emissions of 40 percent below 2013 levels by 2030 for methane and HFCs and 50 percent below 2013 levels by 2030 for anthropogenic black carbon.

The SLCP Strategy aims to reduce black carbon emissions by replacing old fireplaces and woodstoves with EPA certified wood-burning devices, electric, propane, or natural gas heaters. Residential wood combustion is forecast to be the largest individual anthropogenic source of black carbon in 2030, so a reduction of household wood combustion is anticipated to help set California on its path toward meeting SB 1383's 2030 target. Monetary incentives to aid the removal of old wood burning devices have been popular and the SLCP Strategy proposes to work with air districts to encourage the installation of nonwood burning centralized heating in new construction to avoid new residential wood combustion emissions.

Methane emissions are addressed in the SLCP Strategy in the context of agriculture, landfills, and oil and gas industrial activities, which combined account for nearly all of California's methane emissions. Agriculture emission reduction measures include dairy manure management practices, such as switching from flush water lagoon systems to anaerobic digesters or solid manure management practices, and new feeding and dietary practices to reduce methane emissions from dairy and livestock digestive processes. Landfill and wastewater treatment measures include the development of CalRecycle regulations to reduce disposal of organic waste by 50 percent of 2014 levels by 2020 and 75 percent by 2025 and the use of financial incentives and/or regulatory actions to ensure that new and existing wastewater treatment plants implement methane capture systems and maximize digestion of regional organic materials. Oil and gas emission reduction measures include a CARB greenhouse gas emission regulatory standard for crude oil and natural gas facilities, enhanced monitoring of underground gas storage facilities for methane emissions, and efforts to minimize natural gas leaks from state regulated transmission and distribution gas pipelines and facilities.

HFC emissions are tackled by focusing on refrigeration and air conditioning system fugitive refrigerant emissions, which make up the majority of HFC emissions in California. HFC emission reduction measures include an incentive program to encourage the use of low-global warming potential ("GWP") refrigerants, a prohibition on the sale or distribution of refrigerants with 100-year GWP values of 2500 or greater, and a prohibition on the use of high-GWP refrigerants in new commercial, industrial, and residential stationary refrigeration and air conditioning equipment.

HFC emissions are tackled by focusing on refrigeration and air conditioning system fugitive refrigerant emissions, which make up the majority of HFC emissions in California. HFC emission reduction measures include an incentive program to encourage the use of low-global warming potential ("GWP") refrigerants, a prohibition on the sale or distribution of refrigerants with 100-year GWP values of 2500 or greater, and a prohibition on the use of high-GWP refrigerants in new commercial, industrial, and residential stationary refrigeration and air conditioning equipment.

The SLCP Strategy will be integrated into CARB's 2017 Climate Change Scoping Plan Update, which sets forth a comprehensive plan for achieving SB 32's statewide 2030 GHG limit of 40 percent below 1990 levels. Other concurrent planning efforts in California are expected to identify additional activities to reduce SLCP emissions, such as the California Energy Commission's Integrated Energy Policy Report, the Healthy Soils Initiative, and the Forest Carbon Plan.