This story originally appeared on The Guardian and is part of the Climate Desk collaboration.

The climate crisis is coming for some of the world’s greatest surf breaks, submerging some as sea level rises and wiping out others as classic breaks get crushed against coastal developments.

Analysis of dozens of famous waves in World Surfing Reserves (WSR) found that more than three-quarters were at high risk because of changing tide levels, hardened shorelines, and shifting sands.

The impacts matter not only to the surfers catching the waves but also to the communities that depend on the multibillion-dollar surf economy, often located in places with little else.

The waves rated at most risk in the study include the “bombing barrels” of Croyde Beach in North Devon, UK; the point breaks at Noosa in Australia and Oriente Salvaje, El Salvador; and Santa Cruz reefs of California such as Sewer Peak and Wind and Sea.

The best surfing waves are created by intricate combinations of seafloor shape, swell direction, and tide. “Surf breaks are incredibly unique oceanographic phenomena—a confluence of all these factors that fit together just right to make the wave happen—and so those processes are really sensitive,” said Dan Reineman, an associate professor at California State University Channel Islands and a coauthor of the study.

Global heating is pushing up sea level and changing rainfall patterns that affect sediment movement, which can upset the delicate balance and destroy the wave. However, the researchers said the expert local knowledge of surfers could be tapped to help protect the waves.

Trent Hodges, a coauthor of the study and a senior programs manager at Save the Waves Coalition, which launched the WSR program in 2009, said: “Climate change will impact surf breaks all over the world in different ways, depending on their unique geographies. We learned directly from the local surfers how they are seeing their waves change. It’s a canary in the coal mine too—when a wave changes, that often means the beach is changing, and everybody enjoys the beach.”

The study, published in the journal Climatic Change, concludes: “Climate change and coastal management both have significant negative implications for the future viability of multiple surf breaks of global significance and, therefore, the myriad distinct local communities, cultures and economies they support.”

Almost 200 local experts analyzed 57 surf breaks in all but two of the 13 WSRs, spread across eight countries. The researchers said thousands of other surf waves around the world faced similar peril.

A key finding was that where coastlines were more natural, they could adapt better to the changes brought by the climate crisis, by shifting inland and relocating sediments. Development such as sea walls, jetties, and groynes made the beaches and waves less resilient, Reineman said.

Adam Hall, a cofounder of the North Devon WSR, was one of the local surfers who contributed to the study. He said: “North Devon is so special. We have Saunton Sands, a world-renowned longboarding wave with really long, mellow rides, and the UK’s best beach break at Croyde. We’ve got left- and right-hand point breaks and a sheltered spot for when it gets too windy and too big. Whatever you want to do, we’ve got it.”

He said surfing was very important for the local economy, and not just in summer. “Surfers will come throughout the year. They fill up the pubs, restaurants, and car parks when the swells are good in January, February, and March, where if you go to any other tourist destination that doesn’t have surf, they’re dead on their knees.”