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Tourists looking for sun and sand in Mexican resorts like Cancun, Playa del Carmen and Tulum have been disgusted by foul-smelling mounds of sargassum — a seaweed-like algae — piling up on beaches and turning turquoise waters brown, and experts are warning that it may be the new normal.

Mexico's Riviera Maya Caribbean coast provides half the country's tourism revenues and very little sargassum reached it prior to 2014. But a possible combination of climate change, pollution from fertilizers and ocean flows and currents carrying the algae mats to the Caribbean has caused the problem to explode.

Some officials say the vast mats of sargassum filling the Caribbean could be one of the more visible climate-change events because of the sheer number of people who visit the region's beaches.