Planting trees along coastlines with human-made shore defenses, such as dikes, could protect more than 140,000 people from flooding and save up to $800 million from flood damage globally each year, a new study finds.

Places that have mangroves, such as parts of Florida, are better able to withstand the ravages of storms and their powerful waves. But although there is a push to restore mangroves around the world, there are several challenges.

In 2022, Hurricane Ian slammed into southwest Florida. Storm-powered waves reached up to 18 feet (5.5 meters) and devastated coastal communities and infrastructure. The hurricane killed 158 people and generated $110 billion in damage in the state. Authorities say the storm surge, which is when the storm pushes water ashore, was the main cause of deaths.

But places in Florida with mangroves saw 30% less damage than areas without mangroves, saving about $13 billion. “Mangroves act as a sponge to incoming waves,” Daniel Friess, an environmental scientist at Tulane University, told Live Science. “Their dense tangle of aboveground roots are great at soaking up incoming wave energy.”

Mangroves are forests that exist in the intertidal zone between the ocean and land. Their trees can live in the salty water, and they are found in tropical and subtropical coastal zones. Climate change is expected to make hurricanes more frequent, and rising sea levels will drive higher storm surges. Mangroves protect communities and infrastructure from these surges.

They could also help to combat climate change. A 2025 study found that restoring 1.1 million hectares (2.7 million acres) of mangroves globally would remove about 0.93 gigatons of carbon dioxide from the atmosphere. That’s almost triple the emissions from cars in the U.S. It would cost about $10.73 billion to restore those mangroves, according to the study.

Despite their importance, the world’s mangroves are in danger. More than half of Earth’s mangrove ecosystems are at risk of collapse by 2050, according to a 2024 assessment by the International Union for Conservation of Nature. They are being replaced by agriculture and aquaculture.