President Barack Obama smiles upon arrival for the Summit on Climate Change at the United Nations Tuesday, Sept. 22, 2009.
Secretary of State Hillary Rodham Clinton waves upon arrival for the Summit on Climate Change at the United Nations Tuesday, Sept. 22, 2009.
Former Vice President Al Gore enters a press conference during a climate change summit, Tuesday, Sept. 22, 2009, at the United Nations headquarters.
Oscar-nominated actor Djimon Hounsou speaks during a news conference, Tuesday, Sept. 22, 2009, at United Nations headquarters.
French President Nicolas Sarkozy speaks at the summit on climate change at the United Nations headquarters in New York Tuesday, Sept. 22, 2009.
U.N. Secretary General Ban Ki-moon, above, applauds as Japanese Prime Minister Yukio Hatoyama addresses the summit on climate change at the United Nations, Tuesday, Sept. 22, 2009.
Australian Prime Minister Kevin Rudd, left, and South Korean President Lee Myung-Bak chair a discussion on climate change during a climate change summit, Tuesday, Sept. 22, 2009, at the United Nations headquarters.
Finland President Tarja Halonen, left, and Kuwaiti Prime Minister Sheikh Nasser Mohammed Al-Ahmed Al-Sabeh chair a discussion on climate change during a climate change summit, Tuesday, Sept. 22, 2009, at the United Nations headquarters.
Former Vice President Al Gore speaks during a press conference, Tuesday, Sept. 22, 2009, at United Nations headquarters.
Former Vice President Al Gore, left, listens as Prime Minister of Denmark Lars Lokke Rasmussen speaks during a press conference, Tuesday, Sept. 22, 2009, at United Nations headquarters.
Chinese President Hu Jintao addresses the summit on climate change at the United Nations headquarters Tuesday, Sept. 22, 2009.
Secretary of State Hillary Rodham Clinton, left, and United States Ambassador to the U.N. Susan Rice wait for President Barack Obama's address during the Summit on Climate Change, Tuesday, Sept. 22, 2009, at the United Nations.
President Barack Obama approaches the podium to address the Summit on Climate Change at the United Nations, Tuesday, Sept. 22, 2009.
President Barack Obama speaks at the summit on climate change at the United Nations in New York on Tuesday, Sept. 22, 2009.
President Barack Obama, below, shakes hands with U.N. Scretary General Ban Ki-moon after he addressed the summit on climate change at the United Nations, Tuesday, Sept. 22, 2009.