Get ready for a new economic order. In the world 15 years from now, the U.S. will be far less dominant, several emerging markets will catapult into prominence, and some of the largest European economies will be slipping behind.  
That's according to the U.S. Department of Agriculture's latest macroeconomic projections that go out to 2030, displayed in the chart below. The U.S. will just barely remain the global leader, with $24.8 trillion in annual output. The gray bar represents the $16.8 trillion gross domestic product projected for 2015, and the green bar shows how much bigger the economy is expected to be 15 years from now. The country, worth 25 percent of the world economy in 2006 and 23 percent in 2015, will see its share decline to 20 percent. 
China's GDP will grow to more than twice its size today, helping the Asian powerhouse to almost entirely close its gap with the U.S. 
World's 20 Largest Economies in 2030
India, ranked eighth for 2015, will climb past Brazil, the United Kingdom, France, Germany and Japan to take third place. The International Monetary Fund calls India "the bright spot in the global landscape." The country will have the largest workforce in the world within the next 15 years, the IMF notes, and among the youngest.
Other nations won't be so lucky, particularly among developed economies. Japan will see very little growth, pushing it down a spot in the rankings. France will slide three spots, while Italy drops two. 
In the overall ranking, Jamaica will surrender the most ground, bumping down 13 places to 136. Countries with the biggest advances -- like Uganda, which will climb 18 spots to rank 91 -- are concentrated in Africa, Asia and the Middle East. 
The USDA is not the only -- and hardly the most widely-followed -- ranking of global economic growth, though it does offer the advantage of particularly long-term outlooks. The International Monetary Fund's economic outlook only projects out two years. Look out for it later this month. 
And if 15 years is too far out for you, take a look at the fastest-growing economies just for this year. 

For more on the global economy, check out Benchmark: