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Southern California Association of Governments

Welcome to SCAG

SCAG is the nation's largest metropolitan planning organization, representing six counties, 191 cities and more than 18 million residents. SCAG undertakes a variety of planning and policy initiatives to encourage a more sustainable Southern California now and in the future. More About SCAG >
Southern California Association of Governments

Greenhouse Gases

Greenhouse gases (GHG) are gases that trap heat in the atmosphere including carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), and fluorinated gases.  The effect of each gas on climate change depends on how much of the gas is in the atmosphere, how long the gas stays in the atmosphere, and how strongly the gas impacts global temperature.  Read more.

Legal Requirements on GHG Emission Reduction

  • The Global Warming Solutions Act of 2006 (AB 32) , passed by California Legislature and signed into law by Governor Schwarzenegger in 2006, set the 2020 statewide limit of greenhouse gas (GHG) emissions for California.  AB 32 directed the California Air Resources Board (ARB) to prepare and adopt a scoping plan   for achieving the maximum technologically feasible and cost-effective reductions in GHG emissions from sources or categories of sources of GHG by 2020.  ARB is also required to adopt a cap-and-trade program   that establishes a system of market-based declining annual aggregate emission limits for sources or categories of sources that emit GHG emissions, applicable from January 1, 2012, to December 31, 2020.  Read more.
  • To enhance California’s ability to reach the AB 32 goals, Sustainable Communities and Climate Protection Act of 2008 (SB 375)   was enacted to reduce GHG emissions from automobiles and light trucks through integrated transportation, land use, housing and environmental planning. Under the law, SCAG is tasked with developing a Sustainable Communities Strategy (SCS), a newly required element of the 2012 Regional Transportation Plan (RTP) that provides a plan for meeting emissions reduction targets set forth by the California Air Resources Board (ARB).  On September 23, 2010, ARB issued a regional 8% per capita reduction target for the planning year 2020, and a conditional target of 13% for 2035.  Read more 

Inventories of GHG Emissions and Sinks

  • The annual report of U.S. GHG emissions and sinks inventory is developed by the U.S. Environmental Protection Agency (EPA) to tracks total annual U.S. emissions and removals by source, economic sector, and greenhouse gas going back to 1990.  EPA released the most recent 1990-2013 inventory report  in April 2015.  Read more.