This page last reviewed April 6, 2017

Reducing Short-Lived Climate Pollutants in California

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What's New

  • The Final Proposed Short-Lived Climate Pollutant (SLCP) Reduction Strategy and relevant appendices have been released.

SLCP Documents

Final Proposed SLCP Reduction Strategy Final Proposed SLCP Reduction Strategy (posted March 14, 2017)

Response to Comments Received on Revised Draft Environmental Analysis

Public Hearing Notice 

What are Short-Lived Climate Pollutants?

Short-lived climate pollutants are powerful climate forcers that remain in the atmosphere for a much shorter period of time than longer-lived climate pollutants, such as carbon dioxide (CO2). Their relative potency, when measured in terms of how they heat the atmosphere, can be tens, hundreds, or even thousands of times greater than that of CO2. The impacts of short-lived climate pollutants are especially strong over the short term.  Reducing these emissions can make an immediate beneficial impact on climate change.

Short-Lived Climate Pollutants include three main components:

  • Black carbon is a component of fine particulate matter, which has been identified as a leading environmental risk factor for premature death. It is produced from the incomplete combustion of fossil fuels and biomass burning, particularly from older diesel engines and forest fires. Black carbon warms the atmosphere by absorbing solar radiation, influences cloud formation, and darkens the surface of snow and ice, which accelerates heat absorption and melting. Diesel particulate matter emissions are a major source of black carbon and are also toxic air contaminants that have been regulated and controlled in California for several decades in order to protect public health. 
  • Fluorinated gases (F-gases) are the fastest growing source of greenhouse gas emissions in California and globally. They include ozone-depleting substances that are being phased out globally under the Montreal Protocol, and their primary substitute, hydrofluorocarbons (HFCs). Most F-gas emissions come from leaks of these gases in refrigeration and air-conditioning systems. Emissions also come from aerosol propellants, fire suppressants, and foam-expansion agents. 
  • Methane (CH4) is the principal component of natural gas. Its emissions contribute to background ozone in the lower atmosphere (troposphere), which itself is a powerful greenhouse gas and contributes to ground level air pollution. The atmospheric concentration of methane is growing as a result of human activities in the agricultural, waste treatment, and oil and gas sectors. Capturing methane from these sources can improve pipeline safety, and provide fuel for vehicles and industrial operations that displaces fossil natural gas use.

The Short-Lived Climate Pollutant Reduction Strategy

SB 605 (Lara, Chapter 523, Statutes of 2014) directed ARB to develop a comprehensive short-lived climate pollutant strategy, in coordination with other state agencies and local air quality management and air pollution control districts to reduce emissions of SLCPs. SB 1383 (Lara, Chapter 395, Statutes of 2016) directed the Board to approve and begin implementing the plan by January 1, 2018. The Final Proposed SLCP Reduction Strategy was approved by the Board in March 2017.

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Climate Change