Global investors should be more concerned about the fallout from anti-government protests in Hong Kong than the U.S.-China trade war, CNBC's Jim Cramer said Monday, hours after the city's main airport canceled all flights do to demonstrations.

"I just don't think the Chinese communists can avoid it anymore," Cramer said. "The Chinese government is more worried about Hong Kong than they're worried about trade. Because Hong Kong is something that's very visible in Europe."

"This is more serious than the trade talks," he added. "If you want to know what could tip you into a worldwide recession, it is just a shutdown of Hong Kong," a major financial hub in Asia.

Protesters in Hong Kong have been rallying since June, at first in opposition of a proposal that would have allowed extradition to mainland China, a measure critics argue would threaten judicial protections. They want Hong Kong leader Carrie Lam to officially withdraw the extradition bill from future consideration instead of just saying that the measure is "dead."