Alarms are going off in the Taiwan Strait again. The Wall Street Journal reports that China is resuming its military drills in the region following the surprise arrival of a new delegation of U.S. lawmakers.

The drills appear aimed at demonstrating Beijing’s ability to mount a blockade of Taiwan, raising new questions about the impact that a broader and more sustained military action would have on global business.

Experts say a Chinese blockade of Taiwan would cripple global supply chains and raise freight prices in Asia and potentially beyond, because of the outsize role that the island of roughly 23 million people plays in global business.

It would also close off one of the world’s busiest routes, cutting shipping capacity as vessels sail on longer voyages around the region. That would drive up shipping rates, which spiked when tensions arose a couple of weeks ago.