Climate benefits from establishing marine protected areas targeted at blue carbon solutions

Marine protected areas (MPAs) are recognized as highly effective tools for marine conservation.
They may also play an important role in mitigating climate change. A variety
of climate change solutions are rooted in the ocean, centered primarily around “blue
carbon” and the capacity of marine life to sequester carbon dioxide (CO2) with some
potential to reduce emissions. However, the global potential of these solutions remains
misunderstood and untapped. Here, we analyze the potential impact on carbon removal
and emissions reduction of adopting six ocean-based solutions in MPAs: coastal wetlands
protection, coastal wetlands restoration, macroalgae protection, macroalgae restoration,
seafloor protection, and seaweed farming. The carbon removal and avoided
emissions achieved by implementing these solutions globally through 2060 were estimated
using meta-analysis of existing studies. Applying all six ocean solutions under
global implementation scenarios yields total emissions reduction by 2060 of 16.2 ±
1.82 gigatonnes of carbon dioxide equivalent (GtCO2-eq) for the plausible scenario and
24.8 ± 2.46 GtCO2-eq for the ambitious scenario. That equates to around 2% of the
total carbon mitigation needed to meet the Paris Agreement goals of limiting global
warming to 2 °C by 2050. Around 70% of this reduction is attributable to carbon
removal and 30% to avoided emissions. Enhancing MPAs’ blue carbon potential could
be a key contributor to drawing down carbon and could provide many additional benefits
to the marine environment and human society, such as rebuilding biodiversity and
sustaining food production. However, more regional-scale studies are needed to inform
the best strategies for preserving and enhancing carbon removal in ocean sinks.