Conservation of blue carbon ecosystems for climate change mitigation and adaptation

Emission of greenhouse gases, including carbon dioxide (CO₂), has been the main cause of climate change and global warming since the mid-20th century. Blue carbon (BC) ecosystems, which include tidal marshes, mangroves, and seagrass meadows, play a key role in climate change mitigation and adaptation. Despite occupying only 0.2% of the ocean surface, they contribute 50% of carbon burial in marine sediments, equivalent to the sequestration of 1%-2% of current global CO₂ emissions from fossil fuel combustion. Conversely, damage to these ecosystems risks the release of that carbon back to the atmosphere. Conserving and restoring BC ecosystems not only maintains CO₂ sequestration capacity but also services essential for climate change adaptation along coasts, including prevention of shoreline erosion. However, BC ecosystems rank among the most threatened ecosystems on earth. Urgent action is needed to prevent further degradation, to avoid additional greenhouse emissions, as well as restoring degraded habitats to recover their climate change mitigation potential.