Per hectare, mangrove forests store up to 1,000 tonnes of carbon, three to five times more than an equivalent area of tropical rainforest. For decades this was considered irrelevant because the forests were shrinking. Shrimp farming and coastal development, particularly in Southeast Asia, were clearing mangrove stands. A study published June 4, 2026, in Science with 40 years of satellite data now shows that this trend has reversed for roughly 16 years. The net loss over the entire observation period amounts to only one percent.
What mangroves are and why they matter
Mangrove forests grow in the tidal zone of tropical and subtropical coasts, where freshwater meets saltwater. Their distinctive aerial roots emerge from the water and stabilize coastlines against erosion and storm surge. Within these root networks, fish, shrimp, and crustaceans spawn; the forests serve as nurseries for a large portion of commercially important seafood species in the tropics.
But their most significant contribution is to the global carbon cycle. According to the Blue Carbon Initiative, mangrove forests store roughly 1,000 tonnes of carbon per hectare, three to five times more than equally large tropical rainforests. The difference lies in the soil. While tropical rainforests bind most of their carbon in above-ground biomass, mangroves bury approximately 75 percent in oxygen-poor sediments beneath their roots, where it accumulates over millennia. Destroyed mangroves therefore release not only currently sequestered carbon but also centuries-old carbon reserves.
This made the decline of recent decades so consequential. Aquaculture facilities for shrimp farming, agricultural conversion, and coastal development cleared mangrove forests, particularly in Southeast Asia and Latin America.
Four decades of loss, sixteen years of recovery
The study, lead-authored by Zhen Zhang, a postdoctoral researcher at Tulane University School of Science and Engineering, analyzed four decades of Landsat satellite imagery from NASA's Earth Observation Program, the most comprehensive dataset for such global analysis. Co-authors include Thomas Worthington, director of the Global Coastal Wetlands Lab at the University of Cambridge, and Tulane Professor Daniel Friess, who leads the Mangrove Lab at the university.
The study's core findings, published in Science (DOI: 10.1126/science.aec9773): Between the late 1980s and 2010, approximately 2,900 square kilometers of mangrove forest were lost globally. Then the trend reversed. For roughly 16 years, beginning around 2010, gains from natural regeneration and active restoration projects have exceeded losses from clearing. Over the entire 40-year period, net loss amounts to roughly one percent of the original area.
Zhang called the result a global turning point for mangroves in a Tulane press release, pointing to their potential as nature-based solutions for climate action and coastal protection. Daniel Friess added that mangroves now showed net global growth and that the degradation rate was slowing.
In comparison: What other ecosystems show
The mangrove recovery does not stand alone. Two other ecosystems demonstrate how policy measures can reverse loss trends and where the limits lie.
Costa Rica offers the clearest example of a successful reversal in forest coverage. By the late 1980s, intensive clearing for cattle ranching had reduced the country's forest cover to 21 percent. The government then established a national Payment for Ecosystem Services program that compensated landowners for forest conservation. Today, forest cover exceeds 60 percent. Over roughly 50 years, the forest base has tripled. The mangrove pattern follows similar logic. Where political protection and economic incentives combine, the trend reverses.
Coral reefs demonstrate the limits of such recovery. According to an IPCC interim report, global coral reefs have lost roughly half their living reef structure since the 1950s. Recovery rates lag far behind loss rates. The difference from mangroves lies in climate dependence. Corals respond directly to rising ocean temperatures with bleaching events. Mangrove forests are more temperature-tolerant and regenerate much faster after local disturbances. This makes them more accessible restoration targets.
What threatens success: Coastal development and climate extremes
The recovery is real but not assured. Three risks confront progress.
First, coastal development. Despite the positive global trend, mangroves continue to be cleared locally for aquaculture, tourism, and settlement. In some regions of Southeast Asia and West Africa, losses and restoration occur simultaneously, with regionally varying net outcomes.
Second, climate extremes. The study cites the Mississippi River Delta and Texas, where mangrove forests had expanded northward in recent decades until an extreme freeze event in 2021 devastated the Texas stands. With increasing frequency of extreme weather, the stability of newly colonized mangrove areas becomes harder to predict.
Third, the lack of uniform global monitoring. The Landsat study provides the most complete picture to date, but only now is there a methodologically consistent baseline. Thomas Worthington of the University of Cambridge recommended in the study that the most direct protection focus on ending deforestation. The most effective way to protect mangroves is to stop cutting them down. Active restoration can supplement but cannot replace this effect.