(CNSNews.com) - Global warming is one of the greatest threats to U.S. national security and the world, according to a panel of well-known environmentalists who spoke Tuesday at the self-described "progressive" Take Back America conference in Washington, D.C.

In their discussion, "Global Warming: Meeting a Real and Present Danger," the panelists warned that, despite a rising movement to debunk the theory of global warming as a myth, climate change threatens America's security. Two panelists also claimed that no matter the outcome of November elections, U.S. environmental policy will improve.

John Podesta, president/CEO of the liberal America Center of Progress and former chief of staff to President Bill Clinton, called global warming a "severe national security problem" and noted that President Bush, who has made national security a top priority, has nonetheless nearly ignored the problem of climate change.