The document predicts that abrupt climate change could bring the planet to the edge of anarchy as countries develop a nuclear threat to defend and secure dwindling food, water and energy supplies. The threat to global stability vastly eclipses that of terrorism, say the few experts privy to its contents. 'Disruption and conflict will be endemic features of life,' concludes the Pentagon analysis. 'Once again, warfare would define human life.'

The findings will prove humiliating to the Bush administration, which has repeatedly denied that climate change even exists. Experts said that they will also make unsettling reading for a President who has insisted national defence is a priority.

Climate change 'should be elevated beyond a scientific debate to a US national security concern', say the authors, Peter Schwartz, CIA consultant and former head of planning at Royal Dutch/Shell Group, and Doug Randall of the California-based Global Business Network. An imminent scenario of catastrophic climate change is 'plausible and would challenge United States national security in ways that should be considered immediately', they conclude. As early as next year widespread flooding by a rise in sea levels will create major upheaval for millions.

Last week the Bush administration came under heavy fire from a large body of respected scientists who claimed that it cherry-picked science to suit its policy agenda and suppressed studies that it did not like. Jeremy Symons, a former whistleblower at the Environmental Protection Agency (EPA), said that suppression of the report for four months was a further example of the White House trying to bury the threat of climate change.

Bob Watson, chief scientist for the World Bank and former chair of the Intergovernmental Panel on Climate Change, added that the Pentagon's dire warnings could no longer be ignored. 'Can Bush ignore the Pentagon? It's going be hard to blow off this sort of document. Its hugely embarrassing. After all, Bush's single highest priority is national defence. The Pentagon is no wacko, liberal group, generally speaking it is conservative. If climate change is a threat to national security and the economy, then he has to act. There are two groups the Bush Administration tend to listen to, the oil lobby and the Pentagon,' added Watson.

Already, according to Randall and Schwartz, the planet is carrying a higher population than it can sustain. By 2020 'catastrophic' shortages of water and energy supply will become increasingly harder to overcome, plunging the planet into war. Randall told The Observer that the potential ramifications of rapid climate change would create global chaos. 'This is depressing stuff,' he said. 'It is a national security threat that is unique because there is no enemy to point your guns at and we have no control over the threat.' Randall added that it was already possibly too late to prevent a disaster happening.