In 2007, the transportation sector accounted for 29 percent of the total greenhouse gas emissions in the United States – with nearly 60 percent of these emissions resulting from gasoline consumption from personal vehicle use (US EPA, April 2009). However, the transportation sector in many states such as California, Washington and Oregon accounts for a greater portion of the GHG inventory due to clean infrastructure in the electricity sector.
The Western Climate Initiative (WCI) is a collaboration of governors to address the issues of climate change. WCI has set an overall regional goal of reducing aggregate emissions to 15% below 2005 levels by year 2020. The WCI is also designing a market-based mechanism for achieving these reductions and has completed a draft design of a regional cap-and-trade program (July 2008). The partners of WCI are: Arizona, British Columbia, California, Manitoba, Montana, New Mexico, Ontario, Oregon, Quebec, Utah, and Washington.
The Pew Center on Global Climate Change provides a comprehensive list of actions taken at the state and regional level to address greenhouse gas reduction. The following list includes US states that have set greenhouse gas reduction targets within the Western Climate Initiative:
- Arizona – GHG reduction to 2000 levels by 2020; 50% below 2000 levels by 2040 (Executive Order 2006-13, 2006)
- California – GHG reduction to 1990 levels by 2020; 80% below 1990 GHG levels by 2050 (AB 32, 2006; Executive Order S-3-05, 2005)
- Montana – GHG reduction to 1990 levels by 2020 (Western Climate Initiative, 2007)
- New Mexico – 10% GHG reduction below 2000 levels by 2020; 75% below 2000 emissions levels by 2050 (Executive Order 2005-033, 2005)
- Oregon –10% GHG reduction below 1990 levels by 2020; 75% below 1990 levels by 2050 (HB 3542, 2007)
- Utah – GHG reduction to 2005 levels by 2020 (State Department of Environmental Quality, 2008)
- Washington – 25% GHG reduction below 1990 levels by 2035; 50% below 1990 levels by year 2050 (Executive Order 07-02, 2007; HB 2815, 2008); 18% VMT/capita reduction below business-as-usual projections by 2020; 30% by 2035; 50% by 2050 (HB 2815, 2008)