NEW YORK - February 25, 2011 - The world is going to become richer and richer as developing economies play catch up over the coming years, according to Willem Buiter, chief economist at Citigroup.

"We expect strong growth in the world economy until 2050, with average real GDP growth rates of 4.6% per annum until 2030 and 3.8% per annum between 2030 and 2050," Buiter wrote in a market research. "As a result, world GDP should rise from $72 trillion in 2010 to $380 trillion dollars in 2050," he wrote.

As the world watches oil prices rise sharply amid unrest in the Middle East, Buiter's analysis of the world's long-term prospects offer some hope that better times are ahead but if he is correct, power will shift from the West to the East very quickly.

"China should overtake the U.S. to become the largest economy in the world by 2020, then be overtaken by India by 2050," he predicted.