Ocean warming projected to stall expected mangrove recovery

Increasing ocean temperatures will erase mangrove restoration gains expected to occur due to economic development and conservation, according to a new study from researchers at UC San Diego’s Scripps Institution of Oceanography.

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The study, published in Environmental Research: Climate, projects that by 2100 the world would lose out on some 150,000 hectares (370,000 acres) of mangroves and associated ecosystem services worth $28 billion annually, with Asia bearing nearly two-thirds of these losses. The findings bolster the economic case for reducing greenhouse gas emissions and suggest that conservation targets for mangroves may need to become even more aggressive to outpace climate change, said the authors.

Mangroves are salt-tolerant trees with intricate, exposed roots that grow in intertidal zones in tropical and subtropical regions. The coastal wetlands they form protect coastal human communities from storm surges and tsunamis, create habitat for fish and other wildlife, store carbon and improve water quality.

After decades of heavy losses, mangrove forest destruction has slowed due to increased recognition of their importance as well as economic development.

“As a country gets richer you tend to see an initial increase in environmental destruction, but once a place achieves a certain level of economic development the environment degradation starts to diminish,” said Katharine Ricke, a climate scientist at Scripps and coauthor of the study.

Climate change, however, is warming the world’s oceans, and in some parts of the world, these increasing temperatures can exceed the limits of what mangroves can tolerate.