Opinion | The Panama Canal Has a Big Problem, but Its Not China or Trump

In 2023, on a research trip to Panama, I booked a day tour of the Panama Canal.I expected to hear the usual story about the canal’s epic construction, importance in world trade and successful expansion to allow for larger modern ships.

What I did not expect was the overwhelming sense of concern, even panic, among people who depend on the canal for their livelihoods.It was July, the middle of Panama’s rainy season.But the rains had been sparse, and water levels in the canal had sunk to troubling lows.

Without freshwater from rain, our guide explained, the locks on the canal could not operate.I remembered that visit after President-elect Donald Trump said recently that the Chinese were threatening America’s interests at the canal, and he engaged in some saber rattling by suggesting that the United States could take back control of the passage, which was returned to Panama exactly 25 years ago Tuesday.The handover treaties were a signature achievement of President Jimmy Carter, who died on Sunday; Mr.

Trump’s comments were in keeping with longstanding criticism that the move was a strategic mistake.But Mr.Trump misunderstands the true threat to U.S.

commerce through Panama.If the goal is securing affordable access to the transit point over the long term, it is climate change, not Chinese influence, that U.S.

policymakers should worry about.Here’s why.Sending a single ship through the canal’s locks can use around 50 million gallons of water, mainly freshwater collected from Lake Gatún.

Though the canal is, for the moment, operating at full capacity, a drier climate and greater demand for drinking water have in recent years reduced the volume of available water.That has forced the state-run Panama Canal Authority at times to limit the number of daily passages through the canal, at one point by as much as 40 percent.With less rain, the reservoirs fill up more slowly, which means less water available to operate the locks, which means fewer ships can pas...