The paper is an overview of the current understanding of methane (CH4) emissions from landfills that contribute to global climate change. The factors affecting landfill emissions are described and the uncertainties are identified. There appears to be a consensus in the international community that there are large uncertainties in the current estimates of CH4 emissions. The work that is planned by the U.S. EPA to improve the understanding of global emissions from landfills is described in the paper. The work is planned in coordination with efforts in the U.S., the United Kingdom, Germany, India, and other countries who are interested in working to improve the understanding of the emissions from landfills and how these emissions can be prevented or mitigated. CH4 is responsible for almost 20% of current increases in commitment to global warming. Major anthropogenic sources of CH4 include landfills, coal mining, and the production and distribution of natural gas.