Global mangrove estimates show recent gains, but regional losses continue
The story at a glance
Global Mangrove Watch (GMW) reports a net increase of about 477 km² in mangrove extent between 1985 and 2025, equivalent to approximately 0.3% over the period. The trend is uneven: gains in some countries coexist with substantial long-term losses elsewhere.25
A separate peer-reviewed study also finds a shift towards net gains around 2010, but estimates that mangrove extent in 2023 was still 0.5% below its 1980s level, with uncertainty of ±1.4%. The estimates use different datasets and periods and should not be treated as directly equivalent.4
The story in brief
What you need to know
- GMW’s reported global increase is modest: about 477 km², or 0.3%, across four decades. A positive net balance does not mean that losses have ended, or that every region is recovering.25
- The gains and losses are geographically uneven. GMW figures reported by Wetlands International identify gains in India, Australia, the Philippines, Pakistan and Senegal, alongside significant long-term losses in Indonesia, Myanmar, Malaysia and Nigeria.51
- The Science study, based on Landsat data covering 1984–2023, finds that the balance shifted from net loss to net gain around 2010. Across the full period, however, its estimate is a marginal 0.5% decline, with uncertainty of ±1.4%.4
- The datasets do not give the same cumulative estimate. GMW reports a gain for 1985–2025, whereas the Science study estimates a small decline through 2023. Their differing methods and end dates mean the figures should be presented separately, not as a direct contradiction.234
- The reported increases cannot be attributed solely to restoration or stronger protections. Sources also identify natural expansion and regrowth, and potentially changes in river and sediment flows associated with upstream deforestation or mining, as contributors in some places.154
Conservation context
Why this matters
A global net gain can obscure ongoing losses in particular countries. Reading the headline trend alongside regional figures and the separate study’s estimate gives a more qualified picture of how mangrove extent has changed.45
The developing story
What happens next
Further comparisons could clarify how much of the measured increase represents mature, ecologically functional forest and how different drivers contribute in individual countries. The supplied reporting also leaves open whether recent gains will persist amid continuing local pressures.145
Established evidence
What we know
- GMW version 4.1 maps 41 annual epochs from 1985 to 2025 using satellite data.3
- JAXA describes the 1985–2025 time-series raster as having 30-metre pixel spacing. GMW-related material also describes new baseline maps at 10-metre resolution; that does not mean the full time series is uniformly mapped at that resolution.351
- The monitoring sources describe a broad recent improvement in the global balance, while also reporting continuing long-term losses in several countries.125
Open questions
What we don't know
- The supplied sources do not establish how much of the net gain is mature, ecologically functional forest rather than newly established or sparse cover.15
- They do not quantify the relative contributions of natural expansion, restoration, protection and changes to land use or sediment flows in individual countries.145
- A direct comparison of the GMW and Science-study estimates using harmonised definitions, baselines and time periods remains an open question.234
- The reporting does not establish whether recent gains will persist as mangroves face local pressures including clearing, pollution, storms and erosion.15
Source coverage
