Briefing heldDecember 2020 CCST Expert Briefing Series A Carbon Neutral California One For more details Pager about this briefing: Blue Carbon Sequestration along California’s Coast ccst.us/expert-briefings

Select Experts The following experts can advise on Blue Carbon pathways:

Joanna Nelson, PhD Founder and Principal LandSea Science [email protected] http://landseascience.com/

Expertise: salt marsh ecology, coastal ecosystem conservation and resilience

Lisa Schile-Beers, PhD Senior Associate Silvestrum Climate Associates Figure: Carbon cycles in coastal (blue carbon) habitats (The Watershed Company) Research Associate Smithsonian Environmental Background Research Center • Anthropogenic carbon emissions are a • Blue Carbon refers to carbon stored by [email protected] leading cause of climate change. coastal ecosystems including wetlands, salt Office: (415) 378-2903 marshes, seagrass meadows, and kelp forests. Expertise: wetland and marsh ecology, • California has set an ambitious goal of being carbon cycling, and sea level rise carbon neutral by 2045. • Restoring coastal habitats can increase blue • A combined approach of reducing emissions carbon sequestration and contribute to Melissa Ward, PhD and sequestering carbon – physically state goals. Post-doctoral Researcher removing CO2 from the atmosphere and San Diego State University [email protected] storing it long-term – can help California • Restored coastal habitats also provide many https://melissa-ward.weebly.com reach its goals. other co-benefits. Expertise: carbon storage in seagrass, SEQUESTERING Blue Carbon marsh, and kelp ecosystems in California’s Coastal Ecosystems Lisamarie Per unit area, coastal wetlands, marshes, and Benefits of Blue Carbon Habitats Windham-Myers, PhD eelgrass meadows capture more carbon than 1. Reduced atmospheric CO2 levels Research Ecologist terrestrial habitats such as forests. However, 2. Protect captured CO2 in the ground USGS Water Mission Area these blue carbon habitats are rapidly being lost from being released to atmosphere [email protected] Office: (650) 329-4447 worldwide, as well as in the U.S., which results in 3. Improved water quality released carbon emissions to the atmosphere 4. Improved biodiversity and fish habitat Expertise: wetland ecology, carbon and reduced carbon sequestration. sequestration, and other greenhouse 5. Improved sea level rise buffer gas cycling If restored and protected, blue carbon 6. Improved resilience to climate change along the coast habitats accomplish two goals with respect CCST Contact: to greenhouse-gas emissions: 1) avoiding Restoring and protecting California’s coastal Sarah Brady, PhD Deputy Director added emissions to the atmosphere from the habitats would have a measurable contribution [email protected] destruction of these habitats’ large carbon to California’s negative carbon emission goals. reservoirs, and 2) contributing to continued Blue carbon habitats also provide additional carbon trapping and sequestration in co-benefits, including biodiversity, coastal perpetuity and therefore further supporting protection from storm surge, essential fish Download this Document the achievement of carbon neutrality goals in habitat, and recreation and tourism value for geographies such as California. people. ccst.us/expert-briefings BLUE Carbon Sequestration in Coastal Habitats 1 2

Photo: Tomales Bay at low tide (Melissa Ward) Photo: Subtidal eelgrass in Mission Bay, San Diego (Melissa Ward) Blue Carbon Cycles Seagrass Meadows Coastal habitats remove carbon from the atmosphere A comprehensive carbon stock accounting for the state through photosynthesis as plants grow and build biomass that includes seagrass habitats has not been done. Work and soil. Carbon can be stored in above-ground biomass is currently underway to quantify sediment carbon stocks for decades and in sediments for thousands of years. in seagrass meadows in several sites in California. Acres of habitat in California: Measuring carbon stocks that have already been captured 14,800 acres (60 km2) of seagrass habitat (CDFW) by coastal habitats – and the rate at which more carbon is sequestered – is the first step in understanding their Annual Sequestration rate: blue carbon potential in California. Researchers use a 1.58 - 14.2 g c/m2/yr (Poppe & Rybczyk 2018) combination of field measurements and modeling methods Estimated total annual sequestration potential in CA*: to quantify carbon stocks and sequestration rates. Equivalent to removing ~ 500 cars from the road

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Photo: Kelp Forest, Channel Islands National Park (NPS) Photo: Tidal marsh (Melissa Ward) Kelp Forests Wetlands and Marshes There is scientific uncertainty as to whether kelp can play Statewide, there is relatively good carbon and net GHG a significant role in blue carbon sequestration. Kelp attach accounting in salt marsh habitats across the state based to rocky substrates and do not contribute to soil-building on a series of field studies, including projects from the processes. The extent to which kelp settles to the deep CDFW Wetlands and Watersheds GGRF program. ocean bottom where it would be sequestered for millennia Acres of habitat in California: is an active area of research. 296,500 acres (1,200 km2) of tidal marsh (source CDFW) Acres of habitat in California: Annual Sequestration rate: 17,800 acres (72 km2) of kelp forest (source CDFW) 200 g c/m2/yr (Wedding et al, in press) Sequestration rate: Estimated total annual sequestration potential in CA*: Currently uncertain, active area of research. Equivalent to removing ~133,800 cars from the road

* Based on an average annual emissions of ~ 4.6 metric tons of CO2 per car

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