Protecting coastal ecosystems, the world’s blue carbon sink


Coastal ecosystems, or coastal wetlands, are one of the world’s most important ecological carbon sinks, storing roughly 50% of all carbon buried in the ocean. They act as “carbon stores… known as ‘blue carbon’ because they are located in places where the land meets the sea.” Simply put, coastal wetlands are the world’s blue carbon sink, and protecting them contributes to climate change mitigation and adaptation worldwide.

A healthy wetland is one that “can keep carbon stored away for millennia.”  When coastal ecosystems are increasingly threatened by climate change effects and are being destroyed, they release approximately 450 million metric tons of carbon dioxide worldwide. Carbon dioxide, nitrous oxide, and methane are all greenhouse gases (GHG). Salt marshes, mangrove forests, and sea grasses provide locations for diverse habitat, offer feeding grounds for numerous species, and act as sponges that retain millions of gallons of floodwater.

The protection of coastal ecosystems has ecological and cultural benefits. As the breeding ground for fish habitat, coastal wetlands are important food sources. Coastal wetlands are also areas of environmental significance and cultural and spiritual heritage for Indigenous peoples, from the Seychelle Islands to the Arctic shoreline. Indigenous Peoples’ knowledge and stewardship are crucial to the successful management of coastal wetlands.

Coastal wetlands can act as buffers that improve the resilience of coastlines during severe storms. Furthermore, ongoing climate change effects such as sea level rise and soil erosion are damaging coastal ecosystems. However, uncontrolled coastal land development, conversion of wetlands into agricultural use, and greenhouse gas emissions from cars, shed more light on human-made impacts on coastline destruction.

The protection of coastal wetlands has been recognized by the United Nations Framework Convention on Climate Change (UNFCC) as a key contributor to climate change mitigation and adaptation. As signatories of the Paris Agreement, countries can take actions to reduce, if not to eliminate, harmful greenhouse gas emissions and to facilitate restoration of the coastal wetlands and other natural areas to meet climate mitigation and adaptation targets. Canada’s 2021 updated Nationally Determined Contribution (NDC) under the Paris Agreement “is to reduce emissions by 40-45% below 2005 levels by 2030” and to “[reduce] its emissions to net-zero by 2050.” However, specific action plans for curbing emissions, which should include restoring natural areas, must be supported, and implemented. Indigenous climate leadership is addressed in Canada’s revised NDCs, noting support for “Indigenous-led and delivered solutions, equipping Indigenous Peoples with equitable resources, and ensuring appropriate and timely access to funding to implement self-determined climate action.”

Protecting coastal wetlands, the blue carbon sinks of the planet will require ongoing research, policy, and government action worldwide. The World Water Forum in 2022 will be held in Dakar and offers an opportunity for countries to review sustainable development goals (SDGs) and the 2030 Agenda of Sustainable Development, including addressing the lack of access to safe drinking water among First Nations communities, eliminating chemical pollution of watersheds, and upholding human rights to clean water and sanitation.

By Leela Viswanathan


(Image Credit: James Park, Unsplash)