Congress and the Obama administration are advancing policies directly aimed -- for the first time -- at cutting emissions from burning carbon fuels. The Environmental Protection Agency plans to regulate greenhouse-gas emissions, which scientists link to global warming. The House recently passed a comprehensive energy bill that would institute a "cap-and-trade" system imposing an increasingly tight cap on carbon emissions by requiring polluters such as electric-power companies to buy emission permits or switch to cleaner energy sources. The legislation is backed by most major energy and environmental groups. Some critics say the bill is fatally flawed, however, partly because the trading market in which big carbon-emitting companies may buy unused pollution permits will make carbon-fuel prices too unpredictable and open to manipulation. It's also unclear whether public support for regulating carbon will continue if the effort significantly raises prices for electric power and manufactured goods.

Marcia Clemmitt is a veteran social-policy reporter who joined CQ Researcher after serving as editor in chief of Medicine and Health, a Washington-based industry newsletter, and staff writer for The Scientist. She has also been a high school math and physics teacher. She holds a bachelor's degree in arts and sciences from St. Johns College, Annapolis, and a masters degree in English from Georgetown University.