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Blu Carbon California: Incorporating Blue Carbon Science into Climate Policy Solutions

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California is home to a diversity of coastal ecosystems like tidal marshes, seagrass beds, and estuaries. These ecosystems provide flood and storm protection, healthy habitats for fish and birds, and recreational spaces. They may also play an important role in addressing climate change.

A new COS and Natural Capital Project study in Global Environmental Change investigates the carbon sequestration potential of habitats along the California coast and details pathways incorporating carbon-capturing habitats into climate change policy.

“Coastal habitats play a critical role in mitigating the drivers of, and impacts from, a changing climate.” —Eric Hartge, COS Research Development Manager

In November 2020, the United States temporarily withdrew from the International Paris Agreement. This action indicated the increasing importance for state and local governments to uphold their commitment to reducing carbon emissions.

California has a goal to reach net zero greenhouse gas emissions by 2045, a commitment that will require the state to take advantage of negative emissions opportunities.

 "Blue carbon" ecosystems, coastal and marine habitats that capture and store high amounts of carbon in soil and plant matter, could contribute to win-win solutions that benefit the environment and people.

What are blue carbon ecosystems?

Coastal blue carbon habitats include salt marshes, seagrass beds, and mangroves. In the past, carbon sequestration potential has mainly been considered in forest ecosystems, while blue carbon habitats have been overlooked. Yet, these habitats can store over ten times more carbon than terrestrial ecosystems like forests, making them a valuable asset in achieving carbon sequestration goals. Once the carbon enters the soil, it may stay there for decades or even millennia.

The research team used the InVEST Coastal Blue Carbon Model developed by the Natural Capital Project to estimate potential carbon sequestration and the monetary value of that sequestration in three study locations — Humboldt Bay, Elkhorn Slough, and the Tijuana River Estuary. The study areas represented a range of coastal habitats in California and are all sites managed by the federal government.

“As carbon markets become more prevalent and demands on the coastline intensify, the mapping and valuation of blue carbon habitats can help managers to prioritize carbon sequestration hot spots for coastal conservation or restoration.” — Lisa Wedding, former COS research associate

At one site, Elkhorn Slough, the carbon sequestration services of the tidal marsh habitat were projected to be worth $4.8 million to $9.7 million in California's carbon market value by 2100. These estimates contributed to policy recommendations about how California might better include blue carbon habitats in climate policy and land use planning.

In addition to the Global Environmental Change study, the research team developed a policy brief to highlight key points for policymakers in California.

As California and other states take action to meet their climate goals, blue carbon habitats can provide an important pathway toward solutions. Studies that map and place value on these ecosystems can be directly incorporated into policy frameworks and inform ecosystem monitoring and management.

"Amplifying the sequestration role of coastal vegetation can provide a pathway for financial investment into helping these ecosystems thrive — along with the services they provide to people and nature." — Eric Hartge

Read the Full Global Environmental Change Study

Read the Policy Research Brief


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