Climate change is the premier environmental challenge of the 21st century. The United States is committed to meeting this challenge, both through domestic actions to reduce greenhouse gas emissions and by helping shape an environmentally sound, cost-effective response under the United Nations Framework Convention on Climate Change (UNFCCC) and its 1997 Kyoto Protocol. Simply put: the United States is committed to completing work on the Kyoto Protocol and to its ratification and entry into force as soon as possible.