GLOBAL TROPICAL AND SUBTROPICAL COASTLINES — Global mangrove forest area has increased more than it has decreased annually since 2010, according to a recent study utilizing 40 years of satellite data. This increase marks a reversal after decades of net loss.
Between the 1980s and 2010, over 12,000 square kilometers of mangroves were cleared across Asia, Africa, and the Americas. The total net reduction in global mangrove coverage since the 1980s is approximately 849 square kilometers, representing a 1 percent decline. Researchers applied machine learning algorithms to satellite imagery to produce annual mangrove distribution records from 1984 to 2023.
The global proportion of dense, closed-canopy mangroves has increased by nearly 20 percent since the 1980s. Dr. Zhen Zhang, a research lead at Tulane University, stated, "After decades of loss, we are finally seeing a global turning point for mangroves. This highlights their strong resilience and their potential as a powerful nature-based solution for climate mitigation and coastal protection."
Mangrove coverage in Indonesia stabilized after reduced clearing for aquaculture and increased coastal protection initiatives. Following Cyclone Nargis in 2008 and a national logging prohibition in 2016, mangrove coverage in Myanmar expanded. Warming temperatures have allowed mangroves to expand into higher latitudes along the U.S. Gulf Coast, with measurable area increases in Louisiana and the Mississippi River Delta since 2012.
Daniel Friess, a professor, said, "We may have underestimated the state of the world's mangroves, as there is evidence that the forests are naturally regenerating and expanding. It means that if we can halt continuing loss through conservation, then we may see an even bigger gain in the world's mangroves." Friess added, "Ground fieldwork is extremely valuable, but it is often costly, and does not allow this large-scale perspective. Satellite observations allow us to fill these gaps and detect long-term changes in places where field measurements are sparse or unavailable."
Despite these overall increases, West and Central Africa continue to experience net mangrove deforestation. Oil extraction infrastructure and pipeline leaks have degraded mangrove habitats in the Niger Delta. Tropical cyclones have also caused measurable annual declines in mangrove coverage in regions such as Australia and the Caribbean. New mangrove growth in some Brazilian coastal areas coincides with increased sediment nutrient runoff from upstream agricultural and mining operations.
A University of Exeter computational model projects that sustained sea-level rise will decrease total mangrove carbon storage capacity over the next century. Luisa Fernanda Gómez Vargas, a researcher, said, "Sea level rise and increased inundation can push the forests beyond their limits, and they will not be able to tolerate this. Mortality and erosion of carbon-rich soils can turn mangroves from a carbon sink into a source that releases stored carbon."