New Report: Restored Estuaries Provide Climate Benefits

Scientists have known that healthy tidal marshes can capture and store carbon from the atmosphere, whereas draining wetlands for agriculture and other uses releases carbon, contributing to climate change.

Now a new report proves marshes can capture carbon in very beneficial amounts.

Arrowhead Marsh_RickLewis
Arrowhead Marsh, Rick Lewis

Restore America’s Estuaries reports that wetlands studied in Washington State’s Puget Sound serve as significant “carbon sinks”.  Restoring just 3,200 acres in the Snohomish Estuary would sequester 2.5 million tons of carbon dioxide over the next 100 years, and scientists say the findings are applicable to other coastal estuaries in Western North America.

This is exciting news for the Bay Area, and another compelling reason for our region to act quickly to restore tidal marsh habitat around San Francisco Bay. The study found that not only can healthy restored tidal marshes store more carbon than previously documented, but they can also adapt to expected rates of sea level rise through the accumulation of soil. So restoring the Bay’s tidal marshes can help with climate mitigation and adaptation.

Check out the full report: Coastal Blue Carbon Opportunity Assessment for Snohomish Estuary: The Climate Benefits of Estuary Restoration.  Blue Carbon is the emerging science of wetland carbon sequestration, while Green Carbon describes the more familiar carbon sequestration in forests.

Scientists agree that the Bay needs 100,000 acres of restored tidal marsh to be healthy. Currently there are 45,000 acres of restored and historic tidal marsh, and 31,000 acres of salt ponds and shoreline parcels in public hands awaiting restoration. The estimated cost of restoring those acres over the next 50 years is $1.4 billion. More than $370 million has already been invested. A reliable source of local funding is needed to leverage state and federal funds, and complete all of this the restoration.  That’s why we’re building support for the work of the Bay Restoration Authority, which is charged with raising and allocating funds for Bay restoration.

The potential benefits to the region are immense. We’ve always known that healthy tidal marshes improve water quality by filtering out pollutants and trash; provide habitat for hundreds of species of wildlife; offer residents a chance to experience the shoreline and its wildlife; provide a buffer against storms and flooding; and create jobs in tourism, shipping, fishing, and recreation. Now this Blue Carbon report adds climate adaptation and mitigation as reasons that restored Bay marshes are crucial to both our economy and quality of life.