By 2100, the global area of mangroves could be reduced by about 150,000 hectares due to warming oceans if greenhouse gas emissions are not urgently reduced.
The degradation of these ecosystems will be accompanied by the loss of around 23 billion euros per year in the services they provide, such as flood control, protection against coastal erosion, protection of fish stocks, and carbon sequestration.
In an article published in the journal Environmental Research: Climate, scientists from the United States, Mexico, and Germany warn that the rising temperature of the oceans, caused by climate change, will undo, by the end of the century, decades of mangrove restoration. Asia will be the region of the planet most affected, with approximately two-thirds of the foreseen losses.
Mangroves are peculiar coastal ecosystems that occur in zones of contact between sea and land. They are formed by salt-tolerant trees whose roots lie above the soil, creating intricate networks that serve as shelter for many species of animals and as nurseries, since the young animals are protected from larger predators that cannot navigate the root labyrinth.
Moreover, they are important carbon sinks, with an absorption ten times greater than many tropical forests. Some estimates point to a storage capacity of about one thousand tonnes of carbon per hectare.
This investigation relied on the analysis of satellite images of mangrove cover between 1996 and 2020, combining them with data on sea surface temperature and global economic indicators.
The scientists say that although projections point to a reduction in mangrove destruction and an increase in efforts aimed at their conservation and restoration, marine warming will be stronger in a future scenario of high emissions, fully offsetting these gains.
Katharine Ricke, from the Scripps Institution of Oceanography, University of California, San Diego, and co-author of the study, explains that “the socioeconomic and political forces are currently strong enough to cancel the climate damages to mangroves, resulting in stability rather than decline.”
However, the researcher says this will not happen unless there are significant reductions in global greenhouse gas emissions.
“We must continue to protect these ecosystems, because they help us both to combat climate change and to adapt to its impacts,” emphasizes Ricke.
