Any major reduction in US greenhouse gas emissions must come from electricity generation, transportation, and industry.

In May, the Senate debated for 30 hours and rejected the Boxer-Warner-Lieberman bill that would have, maybe, reduced US emissions of CO2-equivalent gases enough to bring them back down to 2008 levels by 2025 after letting them rise in the near term. In order to avoid a runaway atmospheric greenhouse effect, the Union of Concerned Scientists has estimated (as have others) that the United States and other industrialized nations must reduce by 2050 their emissions by 80 percent versus 2000 levels. The International Energy Agency has suggested that a 50 percent reduction below 2005 levels might be sufficient to avoid that calamity.

I am posting here the EPA's 2006 inventory (at ES-16) of CO2-equivalent gases to show which industries and activities would need to be most dramatically affected if substantial reductions are to occur.

Electricity generation (mostly coal)    34%

Transportation (mostly oil)                  28%

Industrial                                              19%

Agriculture                                             8%

Commercial                                            6%

Residential                                              5%

Update on Wednesday, July 23, 2008 at 03:05PM by Skeptic

The Kyoto Protocol, which was strongly opposed by the US Senate and never submitted for ratification and from which President Bush formally withdrew in 2001, would have required the US to reduce emissions in the 2008-2012 time frame to 7% below 1990 levels.  This was estimated to require a 20-30% reduction from projected business-as-usual emissions in 2008-12.  Unresolved issues about counting CO2 sinks and purchasing credits from foreign sources made the exact obligation murky.  Source:  Library of Congress-Congressional Research Service via PolicyArchive.