The conference was organized in 2005 as a forum for the nation's mayors to promote local leadership on global warming issues.

This summit comes on the heels of a summer in which much of the U.S. coped with record-breaking heat and devastating floods. It also follows a May report by the Intergovernmental Panel on Climate Change (IPCC), which reaffirmed the urgency of taking steps to combat global warming - including energy-efficiency improvements and investment in clean-burning fuel technologies.

"Over the past three years, the Sundance Summit has been enormously successful in bringing together top climate scientists, public policy experts and over one hundred mayors from throughout the United States to effectively combat global warming," Anderson said in a statement. "At a time when the federal government has abrogated its responsibility to act, municipal leaders have provided tremendous leadership in demonstrating how we can significantly reduce greenhouse gas emissions through energy efficiencies and utilization of clean, renewable sources of energy."

The Summit opened on Sunday. Organizers say it will help translate the IPCC's recommendations into action, providing mayors with an overview of the latest climate science, and offering practical ideas and tools to adopt solutions in their cities, such as purchasing renewable energy, advancing energy efficiency and establishing green building codes.

Another goal, organizers say, is to foster a deeper mayoral understanding and engagement on the issue of emission caps, which are currently under debate at the federal level. Boosting the mayors' voices in state and federal policymaking circles can advance municipal needs and gain traction in federal policymaking.

Redford's Sundance Preserve and Local Governments for Sustainability are co-hosting the event, along with Anderson.