"Doubt it," Bush said on Monday when asked by a member of the audience during remarks in Chicago. "An Inconvenient Truth," the movie by Gore, who lost to Bush in the 2000 presidential election, opens in U.S. theaters this week.

Bush has this year been emphasising a need to wean America off imported oil and devote more resources to developing alternative fuels, but environmentalists have slammed his performance during most of his six years in the White House.