Climate change threatens the United States and all nations. To help address this threat, the United States is taking significant new steps to reduce greenhouse gas emissions. During the past year, President Clinton launched initiatives on bioenergy, wind and solar energy, and Federal energy efficiency. In addition, a growing number of state and local governments and private companies are stepping forward to address climate change with prudent, creative, cost-effective strategies to reduce greenhouse gas emissions. At the same time, the United States continues to invest more than $1 billion per year in research and development on technologies that will help reduce greenhouse gas emissions. In short, from city council chambers to corporate board-rooms, the United States is mobilizing against global warming--the greatest environmental challenge of the 21st century.