US global dominance 'set to wane'
US global dominance 'set to wane' The US navy is likely to have more company in the years to come
US economic, military and political dominance is likely to decline over the next two decades, according to American intelligence agencies.
US clout will weaken as China and India grow more powerful, the National Intelligence Council (NIC) predicts in its latest report on global trends.
The US dollar will no longer be the world's major currency and food and water scarcities will fuel conflict.
The NIC report comes as President-elect Barack Obama prepares to take office.
It will make sombre reading for Mr Obama, says the BBC's Jonathan Beale in Washington, as it paints a bleak picture of the future of US influence and power.
"The next 20 years of transition to a new system are fraught with risks," says Global Trends 2025, the latest of the reports that the NIC prepares every four years in time for the next presidential term.
Nuclear weapons use
The NIC's 2004 study painted a rosier picture of America's global position, with US dominance expected to continue.
But the latest report says that rising economies such as China, India and Brazil will offer the US more competition at the top of a multipolar international system.
There will be greater potential for conflict in the future, the NIC says
A world with more power centres will be less stable than one with one or two superpowers, it says, offering more potential for conflict.
Global warming will have had a greater impact by 2025, triggering food and water scarcities that could fuel conflict around the globe.
And the use of nuclear weapons will grow increasingly likely, says the report, as rogue states and terrorist groups gain greater access to such weapons.
But the NIC does give some scope for leaders to take action to prevent such scenarios.
"It is not beyond the mind of human beings, or political systems, [or] in some cases [the] working of market mechanisms to address and alleviate if not solve these problems," said Thomas Fingar, chairman of the NIC.
And, adds our correspondent, it is worth noting that American intelligence has been wrong before.