Warren Buffett isn’t worried about China surpassing the United States, staying optimistic about America’s future despite other nations rising in power.

"We had four million people here in 1790. We’re not more intelligent than people in China, which then had 290 million people, or Europe, which had 50 million. We didn’t work harder, we didn’t have a better climate, and we didn’t have better resources. But we definitely had a system that unleashes potential," Buffett told Vanity Fair.

"This system works. Since then, we’ve been through at least 15 recessions, a civil war, a Great Depression …. All of these things happen. But this country has optimized human potential, and it’s not over yet," the chief executive of Berkshire Hathaway said.

By 2050, China's economy will be larger than that of the United States, but not by much, HSBC reports.

The financial institution says that China's economy will grow to $24.6 trillion, with the U.S. very close on its heels at $22.3 trillion, according to The Telegraph.

India will trail in third place at $8.2 trillion.

Meanwhile, the Buffett-backed, China-based automaker BYD Co. said its sales fell 15 percent to 51,300 vehicles in December amid rising competition from overseas rivals including General Motors Co. in China, the world’s biggest vehicle market.

The automaker sold 519,806 cars last year, 16 percent more than a year earlier, BYD said in a statement. The figure is 13 percent short of the 600,000 unit target set in August by Shenzhen, southern China-based BYD, which didn’t give a reason for missing the goal.

Chinese automakers such as BYD and Zhejiang Geely Holding Group Co. face a sales challenge from car companies including GM and Volkswagen AG as rising incomes prompt shoppers to buy more expensive foreign models. GM and Tokyo-based Honda Motor Co. are also adding new, lower priced brands to take on local rivals in China.