The debt taken on by the U.S. government and the unprecedented amount of money printed by the Federal Reserve are the biggest risks for 2021, said Jim Rogers, the investor who co-founded the Quantum Fund with George Soros.

Rogers, who is chairman at Rogers Holdings and Beeland Interests in Singapore, told the Reuters Global Markets Forum he expected the next decade to be the most difficult for markets in his lifetime because of the levels of global debt.

"We had a horrible time in 2008 because of too much debt, and since 2008, the debt everywhere has skyrocketed. We can't even count how much the debt is up," Rogers said at the Reuters Global Investment Outlook Summit 2020.

Rogers said he expected the U.S. central bank to continue printing and spending more money under the Democratic administration led by President-elect Joe Biden. Biden is expected to nominate former Federal Reserve Chair Janet Yellen as U.S. Treasury secretary.

"If Janet Yellen is the next Secretary of the Treasury, she loves to print and spend money," Rogers said.

Taking a contrarian view, Rogers said he was not bearish on the U.S. dollar after its correction and on its safe haven appeal.

"There are many bears right now, which usually leads to a rally; so, I'm not bearish on the U.S. dollar," he said.

Bets against the U.S. dollar were expected to linger or even increase in the aftermath of the Nov. 3 presidential election, a Reuters poll found.

Rogers said he was not buying gold or silver at current prices, but was looking at declines in both precious metals to add to his portfolio. He was one of the earliest investors to predict the boom in commodities in the early-2000s.

"Silver is much cheaper than gold on a historical basis. I will buy both (silver and gold), but I will buy more silver."