This book looks at the concerns over climate change, often termed "global warming," which have emerged both in the U.S. and internationally as major policy issues. Reports in 2007 by the United Nations Intergovernmental Panel on Climate Change (IPCC) provided scientific underpinnings for these concerns, and the number of proposals and international meetings devoted to these issues has grown. This book also discusses the major challenges that the United Nations is facing regarding global warming, including finding an agreement on the nature of legally binding commitments, if any, that would prove acceptable to all major players including current parties and developing countries that are major emitters, as well as to the United States. This clash of perspectives is likely to ensure that costs remain a pivotal issue, along with scientific uncertainty, as the climate change policy debate continues.