From the St. Michaels Workshop, these proceedings contain a timely discussion on ethical, environmental, societal, and economic consequences of the use of biotechnology generally and of greenhouse gas mitigation specifically. Greenhouse gas emissions warm the lower layers of the atmosphere and may, consequently, alter the climate of the earth. Even with optimistic assumptions of technological progress, annual carbon emissions could reach 20 billion tonnes by the end of this century. Technical solutions that diminish fossil fuel use (the primary source of carbon dioxide), that increase energy use efficiency, and that capture and sequester carbon emissions are needed to stabilize atmospheric carbon dioxide at levels that will not interfere with the climate system. The St. Michaels Workshop was organized to explore whether and how biotechnology can contribute solutions to the problem of greenhouse gas emissions. The workshop was sponsored by the Office of Science, U.S. Department of Energy, and by the Electric Power Research Institute.