Climate change over the next 20 years could result in a global catastrophe costing millions of lives in wars and natural disasters.

Key findings of the Pentagon Report · Future wars will be fought over the issue of survival rather than religion, ideology or national honor.

• By 2007 violent storms smash coastal barriers rendering large parts of the Netherlands inhabitable. Cities like The Hague are abandoned. In California the delta island levees in the Sacramento river area are breached, disrupting the aqueduct system transporting water from north to south. 
• Between 2010 and 2020 Europe is hardest hit by climatic change with an average annual temperature drop of 6F. Climate in Britain becomes colder and drier as weather patterns begin to resemble Siberia. 
• Deaths from war and famine run into the millions until the planet's population is reduced by such an extent the Earth can cope. 
• Riots and internal conflict tear apart India, South Africa and Indonesia. 
• Access to water becomes a major battleground. The Nile, Danube and Amazon are all mentioned as being high risk. 
• A 'significant drop' in the planet's ability to sustain its present population will become apparent over the next 20 years. 
• Rich areas like the US and Europe would become 'virtual fortresses' to prevent millions of migrants from entering after being forced from land drowned by sea-level rise or no longer able to grow crops. Waves of boatpeople pose significant problems. 
• Nuclear arms proliferation is inevitable. Japan, South Korea, and Germany develop nuclear-weapons capabilities, as do Iran, Egypt and North Korea. Israel, China, India and Pakistan also are poised to use the bomb. 
• By 2010 the US and Europe will experience a third more days with peak temperatures above 90F. Climate becomes an 'economic nuisance' as storms, droughts and hot spells create havoc for farmers. 
• More than 400m people in subtropical regions at grave risk. 
• Europe will face huge internal struggles as it copes with massive numbers of migrants washing up on its shores. Immigrants from Scandinavia seek warmer climes to the south. Southern Europe is beleaguered by refugees from hard-hit countries in Africa. 
• Mega-droughts affect the world's major breadbaskets, including America's Midwest, where strong winds bring soil loss. 
• China's huge population and food demand make it particularly vulnerable. Bangladesh becomes nearly uninhabitable because of a rising sea level, which contaminates the inland water supplies. 

A secret report, suppressed by US defense chiefs and obtained by The Observer, warns that major European cities will be sunk beneath rising seas as Britain is plunged into a 'Siberian' climate by 2020. Nuclear conflict, mega-droughts, famine and widespread rioting will erupt across the world.

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 defense is a priority.

The report was commissioned by influential Pentagon defense adviser Andrew Marshall, who has held considerable sway on US military thinking over the past three decades. He was the man behind a sweeping recent review aimed at transforming the American military under Defense Secretary Donald Rumsfeld.

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.

Senior climatologists, however, believe that their verdicts could prove the catalyst in forcing Bush to accept climate change as a real and happening phenomenon. They also hope it will convince the United States to sign up to global treaties to reduce the rate of climatic change.

A group of eminent UK scientists recently visited the White House to voice their fears over global warming, part of an intensifying drive to get the US to treat the issue seriously. Sources have told The Observer that American officials appeared extremely sensitive about the issue when faced with complaints that America's public stance appeared increasingly out of touch.

One even alleged that the White House had written to complain about some of the comments attributed to Professor Sir David King, Tony Blair's chief scientific adviser, after he branded the President's position on the issue as indefensible.

Among those scientists present at the White House talks were Professor John Schellnhuber, former chief environmental adviser to the German government and head of the UK's leading group of climate scientists at the Tyndall Center for Climate Change Research. He said that the Pentagon's internal fears should prove the 'tipping point' in persuading Bush to accept climatic change.

Sir John Houghton, former chief executive of the Meteorological Office - and the first senior figure to liken the threat of climate change to that of terrorism - said: 'If the Pentagon is sending out that sort of message, then this is an important document indeed.'

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 defense 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.

'You've got a President who says global warming is a hoax, and across the Potomac river you've got a Pentagon preparing for climate wars. It's pretty scary when Bush starts to ignore his own government on this issue,' said Rob Gueterbock of Greenpeace.

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. They warn that 8,200 years ago climatic conditions brought widespread crop failure, famine, disease and mass migration of populations that could soon be repeated.

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. 'We don't know exactly where we are in the process. It could start tomorrow and we would not know for another five years,' he said.

'The consequences for some nations of the climate change are unbelievable. It seems obvious that cutting the use of fossil fuels would be worthwhile.'

So dramatic are the report's scenarios, Watson said, that they may prove vital in the US elections. Democratic frontrunner John Kerry is known to accept climate change as a real problem. Scientists disillusioned with Bush's stance are threatening to make sure Kerry uses the Pentagon report in his campaign.

The fact that Marshall is behind its scathing findings will aid Kerry's cause. Marshall, 82, is a Pentagon legend who heads a secretive think-tank dedicated to weighing risks to national security called the Office of Net Assessment. Dubbed 'Yoda' by Pentagon insiders who respect his vast experience, he is credited with being behind the Department of Defense's push on ballistic-missile defense

Symons, who left the EPA in protest at political interference, said that the suppression of the report was a further instance of the White House trying to bury evidence of climate change. 'It is yet another example of why this government should stop burying its head in the sand on this issue.'

Symons said the Bush administration's close links to high-powered energy and oil companies was vital in understanding why climate change was received skeptically in the Oval Office. 'This administration is ignoring the evidence in order to placate a handful of large energy and oil companies,' he added.

Within twenty to thirty years, the United States will invade Canada to control water for drinking and hydro-electric generation. Dams will be constructed in Canada against the will of the Canadian people.

Within thirty years, a major war will break out in Antarctica over control of Antarctic resources. The last great unexploited continent on Earth will be ravaged.

Within thirty years, after three decades of oil wars, oil production will be approaching exhaustion despite the invasion of every known oil deposit on Earth. Human population numbers which grew because of the availability of oil will crash because alternative energy resources will not be able to handle nine billion people.

Within thirty years, most of the world's temperate and boreal forests will be lost to fires caused by global warming.

Within thirty years, there will no longer be a commercial fishing industry in any of the world's oceans. The fish will be gone, victims of over-fishing, pollution, and global warming.

Over the next three decades, viruses will jump from disappearing species to humanity causing major pandemics. This has already started with SAR's, West Nile Fever, Ebola, Hanta virus, and AIDS. Tuberculosis and malaria will continue to be the major plagues of the under-developed world.

By 2030, the Earth will begin to feel the consequences of what Canadian environmental writer Robert Hunter calls Thermageddon - the consequences of global warming.