Rising Seas Could Turn Mangroves From Carbon Sinks Into Carbon Sources, New Research Shows

New research from the University of Exeter shows that rising sea levels could weaken mangrove forests as carbon sinks. Mangroves cover less than 1% of Earth's surface but store about 15% of ocean carbon. The study found that while some areas may temporarily store more carbon as seas rise, the overall effect across entire forests is a decline in carbon storage over the next century. Drowning trees and eroding soils can flip mangroves from storing carbon to releasing it. The researchers built a new model that links water flow, sediment transport, mangrove growth, and carbon storage across whole forests. They tested IPCC sea level rise scenarios and found that larger increases cause stronger negative effects on carbon storage. This matters for carbon markets and climate policy because mangrove protection and restoration are often used as nature based solutions. If sea level rise turns these ecosystems into carbon sources, the value of mangrove carbon credits could drop and project developers may need to adjust their assumptions.