Maybe it’s a favorite sweater or the device you’re using—something you’ve recently worn, held, or eaten very likely passed through the Panama Canal. The roughly 82-kilometer-long channel connecting the Pacific Ocean and the Caribbean Sea (and, ultimately, the Atlantic Ocean) has been an important artery of global shipping since it opened in 1914. This year, the canal’s relevance has been thrust into the political spotlight as President Donald Trump and Secretary of State Marco Rubio have expressed a desire for the United States to reclaim ownership of it.In recent years the operation of the Panama Canal has been increasingly affected by changes in rainfall, and some data suggest that more shifts are on the way. Delays and reductions in traffic caused by these events portend a more volatile future for the shipping route should climate change alter periodic weather patterns.
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The Panama Canal is built around a system of locks. Ships, ranging from privately owned yachts to gigantic Neopanamax vessels capable of transporting more than 13,000 standard cargo containers, traverse three locks to gain roughly 25 meters in elevation and three locks to drop back down on the other side. That process, which takes 8–10 hours, confers enormous savings in both time and fuel: Ships traveling from the Pacific Ocean to the Atlantic Ocean or vice versa would otherwise take a route around the southern tip of South America.
“Five percent of shipping globally traverses the Panama Canal.”“Five percent of shipping globally traverses the Panama Canal,” said Mark Russo, the chief science officer at Everstream Analytics, a supply chain risk analytics company in Elmhurst, Ill. “It’s a critical artery for global trade.”
Precipitation is key to ensuring that Gatun Lake, the artificial lake that makes up a major part of the canal, remains full enough for Neopanamax ships to safely navigate without running aground. The lake loses water not only to evaporation and deliberate pumping—it supplies some of the region’s drinking water—but also to the very operation of the canal: Each day, about 7 billion liters of water are extracted to supply the locks.
Panama fortunately tends to receive a lot of rainfall: on average, more than 2,000 millimeters each year. “Panama is an incredibly wet country,” said Steve Paton, the director of the Physical Monitoring Program at the Smithsonian Tropical Research Institute in Panama City. But the past 3 decades have included three relatively dry years in the canal’s watershed. In water years 1998, 2016, and 2024 rainfall dipped below 1,750 millimeters. (Water years span the 12-month period between 1 October and 30 September.)
Water-scarce years tend to occur about once every 2 decades, said Patton, and the relatively tight clustering of dry years is unprecedented in the watershed’s 144-year precipitation record, he added