Study Warns Rising Sea Levels Could Turn Mangrove Forests From Carbon Sinks to Carbon Sources
A new computer model developed by University of Exeter researchers finds that rising sea levels are likely to reduce the overall carbon storage capacity of mangrove forests over the next century, potentially turning them into net carbon emitters. Mangroves cover less than 1% of Earth's surface but store roughly 15% of all carbon held in ocean ecosystems, making them critical to climate mitigation efforts. The findings complicate earlier field-based studies that suggested sea-level rise could boost mangrove carbon storage, revealing that local gains may mask broader landscape-scale losses.
Researchers led by the University of Exeter, in collaboration with partners in Colombia and the United States, developed an integrated model linking water flow, sediment transport, mangrove growth and dieback, and carbon storage to assess how sea-level rise affects mangrove ecosystems at a landscape scale. Their model showed that while rising waters can initially increase carbon accumulation at specific locations — consistent with existing field observations — the net effect across entire mangrove forests is a decline in carbon sequestration capacity. As flooding duration exceeds the tolerance of mangrove plants, trees die back and carbon-rich soils erode, converting these ecosystems from carbon sinks into carbon sources. The team tested multiple IPCC sea-level rise scenarios and found that greater rises produced increasingly severe losses in carbon storage. Published in the journal Earth's Future, the study underscores that local-scale measurements can be misleading and that understanding coastal systems as interconnected wholes is essential for accurate climate projections. Separately, a study published in Science based on 40 years of satellite data found that mangrove forests globally have shown unexpected resilience, with gains over the past 16 years outpacing losses and a net area decline of only about 1% since the 1980s — a more optimistic picture than prior estimates. Beyond carbon storage, mangroves provide coastal storm protection, wildlife habitat, and livelihoods for coastal communities, amplifying the stakes of their potential decline.
Limitations & open questions
The modeling study uses a simplified tidal embayment rather than real-world mangrove sites, and the authors themselves note that new assessment approaches are needed to better understand future vulnerabilities. The interaction between the carbon-loss findings and the satellite-based rebound data — specifically whether recovering mangrove area offsets projected carbon losses — is not addressed across any of the sources. Additionally, the role of human interventions such as mangrove restoration programs in altering these trajectories is not discussed.
How coverage differed
Science Daily and Eos both focus exclusively on the carbon storage threat from sea-level rise, emphasizing risk and landscape-scale loss. Live Science introduces a contrasting note of cautious optimism by leading with satellite evidence of global mangrove rebound, framing the ecosystem as more resilient than previously thought before acknowledging the drowning risk.
What different sources said
- Science DailyCenter
Rising seas could drown mangroves and release vast stores of carbon
- Eos (AGU)Center
Mangroves May Be Losing Their Grip on Carbon Storage as Sea Levels Rise
- Live ScienceCenter
Satellite images reveals mangroves rebounding worldwide — but here's why they could still 'drown'
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