United States mitigation efforts

Nationwide efforts in the United States to incorporate a price on greenhouse gas emissions have had limited legislative success to date. In 2009 the U.S. House of Representatives passed the American Clean Energy and Security Act—a cap-and-trade approach that sought to reduce emissions by 83 percent, relative to 2005, by 2050. However, the Senate did not pass the bill and so the bill expired at the end of the legislative session.

State and regional approaches within the United States to price greenhouse gas emissions have begun, however. For example, a collection of northeastern states (currently nine) have formed the subnational scale Regional Greenhouse Gas Initiative (RGGI)—a cap- and-trade system to reduce carbon emissions from power plants within those participating states. The initial emissions targets used by RGGI beginning in 2009 proved to be too high due to larger-than-expected emissions reductions associated with fuel switching (from coal to natural gas) and the economic recession. In 2014 the cap under RGGI was reduced to account for these developments and additional declines of 2.5 percent per year through 2020 were included.

California has also initiated a number of policies to reduce emissions. The centerpiece of these efforts is a cap and trade approach with a goal to reduce emissions to 1990 levels by 2020. Additional legislative efforts in California seek to increase the use of renewable energy for electric power generation (i.e., a renewable portfolio standard), to reduce vehicle emissions, and to enhance carbon sequestration in forests.

In 2007 the U.S. Supreme Court found that the 1990 Clean Air Act requires the U.S. Environmental Protection Agency (EPA) to consider regulating carbon dioxide, the primary manmade greenhouse gas. EPA found in 2009 that greenhouse gas emissions endanger human health and well-being which requires EPA to regulate emissions without further congressional action.

In 2013, EPA proposed new standards to limit carbon emissions from new power plants. In 2014, EPA established a plan to reduce greenhouse gas emissions from existing power plants. The approach requires a roughly 30 percent reduction in carbon emissions by 2030, relative to 2005 emissions. EPA’s approach was upheld by the Supreme Court when challenged.

Nevertheless, President Obama and many members of Congress have stated a preference for addressing climate change through new legislation. Indeed, some legislation under active consideration would block EPA’s authority to regulate carbon dioxide under the Clean Air Act.

The Energy Independence and Security Act of 2007 raised fuel efficiency standards for vehicles. The implications of this for greenhouse gas emissions are hard to assess because increasing efficiency without increasing prices actually encourages emitting activities, as described above.                                             

Coordinated international efforts to reduce greenhouse gas emissions date back to the 1992 United Nations Framework Convention on Climate Change (UNFCCC), which President George H. W. Bush negotiated and Congress ratified. The UNFCC requires the United States and other nations to “avoid dangerous anthropogenic interference with the climate system.” This led to the Kyoto Protocol in 1997, which attempted to establish mandatory cuts for developed countries through a negotiated treaty. Contentious political issues among and within countries have limited participation and success of the Kyoto Protocol and subsequent efforts to adopt binding emission targets internationally.

In 2009 the Copenhagen Accord signaled a shift in the current international approach toward reducing greenhouse gas emissions through voluntary emission targets and actions taken by individual nations with the idea that these voluntary efforts may encourage similar efforts by other nations and thereby create a positive feedback cycle for emissions reductions.