WASHINGTON — The risks of a nuclear weapon being used and wars being fought over dwindling resources will grow during the next 20 years as diminishing U.S. power, a shift of wealth from West to East, the rise of India and China and climate change reshape the world, a new U.S. intelligence study warned Thursday.

"The international system — as constructed following the Second World War — will be almost unrecognizable by 2025 owing to the rise of emerging powers, a globalizing economy, an historic transfer of relative wealth and economic power from West to East, and the growing influence of non-state actors," the report said.

The U.S. "will remain the single most important actor but will be less dominant," in part due to its military power and also because many nations will continue looking to U.S. leadership on issues such as climate change and non-proliferation, the report said.

The current economic upheaval could hasten those trends, but it's unlikely to trigger "a complete breakdown" in the international financial and political order, said the report, entitled "Global Trends 2025: A World Transformed."

"However, the next 20 years of transition toward a new international system are fraught with risks," said the study. "The rapidly changing international order at a time of growing geopolitical challenges increases the likelihood of discontinuities, shocks and surprises. No single outcome seems pre-ordained."

"History tells us that rapid change brings many dangers," it said.