U.S. policymakers at the federal, regional and state level are discussing market-based policies
to reduce carbon dioxide (CO2) and other greenhouse gas (GHG) emissions. Below are answers to
commonly asked questions about the scope of such legislation and the costs and benefits for business.
World Greenhouse Gas Emissions in 2005 is a comprehensive view of global, anthropogenic greenhouse gas (GHG) emissions. The chart in this working paper is an updated version of the original chart, which appeared in Navigating the Numbers: Greenhouse Gas Data and International Climate Policy (WRI, 2005).