After decades of decline, one of the planet's most valuable ecosystems is making a comeback. A new global study published in Science finds that the world now has more mangrove forest than it did at the turn of the century — and the forests that remain are growing denser, older and better at storing carbon.
The research, led by scientists at Tulane University with co-authors from across Asia, the Americas and Europe, used four decades of satellite data to track changes in mangrove cover from the 1980s through 2023. The team found that net loss has nearly stopped, with gains now outpacing losses for the first time on record. Over the full 40-year period, the world ended up with only about a 1% net decline — far smaller than earlier estimates suggested.
"What we're seeing now is a real shift," said Daniel Friess, the Cochran Family Professor of Earth and Environmental Sciences at Tulane and director of The Mangrove Lab. "Mangroves are now showing a net increase globally, and the rate of degradation is slowing. While some mangroves are still being lost, this could make them a rare conservation success story and an important source of optimism for climate action."
Why mangroves matter so much
Mangroves are tropical trees and shrubs that grow along coastlines in salty, tidal water. Their tangled prop roots filter pollutants, trap sediment and shelter the juvenile fish, crabs and shrimp that feed both wildlife and people. Scientists estimate they absorb up to five times more carbon per acre than land-based forests, locking much of it away in waterlogged soils for centuries.
They are also nature's seawall. Communities behind intact mangroves consistently suffer less damage from storm surges and tsunamis — a lesson driven home by the 2004 Indian Ocean tsunami, after which side-by-side comparisons of cleared and forested coastlines convinced many governments to start protecting what was left.
Denser, older, stronger
Beyond simply gaining area, the study highlights another encouraging trend. So-called closed-canopy mangroves — older, dense forests that store far more carbon than young or patchy stands — have expanded globally over the past 40 years. Rates of degradation have dropped sharply since the 1980s, which the authors attribute to a growing patchwork of conservation policies, restoration projects and community-led protection efforts.
That denser canopy matters for the climate. If healthy mangroves are expanding, they are likely capturing more carbon than previous global estimates assumed — making coastal forests an even more attractive piece of the climate puzzle.
From cautionary tale to comeback
The turnaround did not happen by accident. National laws limiting coastal clearing, large-scale replanting efforts in countries like Indonesia, Bangladesh and the United Arab Emirates, and a wave of corporate carbon-credit projects have all helped tip the balance. Local fishing communities, who depend on mangroves for their livelihoods, have also become some of the strongest advocates for keeping the forests standing.
"The story of mangroves is starting to flip," lead author Dr. Zhen Zhang told the BBC, pointing to islands in Indonesia where stands have visibly thickened in recent years. The research also confirms that recovering mangroves can repopulate quickly once pressure is eased, sending out seedlings that drift on tides and take root in mudflats.
Challenges remain: rising seas, aquaculture and coastal development still threaten mangroves in parts of West Africa, the Americas and Southeast Asia. But for the first time in modern history, the global trend line is pointing the right way — and the world's muddiest, most underrated forests are quietly leading one of the most important environmental comebacks of the decade.
