New bill could require ‘blue carbon’ to offset coastal development
SAN DIEGO — Public developments on the California coast would be required to capture carbon in wetlands or other natural systems under an Assembly bill that calls for projects to add “blue carbon” measures to their mitigation plans.
Blue carbon refers to coastal habitat such as wetlands, marshes, kelp forests and eelgrass beds that capture and store carbon in soil, plant matter and the sea floor.
AB 2593, authored by Assemblywoman Tasha Boerner Horvath, D-Encinitas, would require projects on public lands to compensate for greenhouse gas emissions by building or contributing to blue carbon projects.
“It’s a way to develop our coastline, while protecting some of California’s remaining unique important areas,” Boerner Horvath said. “Instead of damaging them, we can double down and reinforce the things that are really valuable — seagrass, flora and fauna.”
If the bill passes, it would add blue carbon mitigation to the suite of factors that the California Coastal Commission considers when it approves coastal permits.
Under California law, any project that affects coastal resources must take measures to avoid or minimize its negative impact. If it can’t avoid that entirely, developers must offset the effects of the project with mitigation measures that replace or restore the resources it will damage.
For projects that affect tidal or ocean habitat, that may include planting new eelgrass beds or restoring marshland. For instance, efforts to widen Interstate 5 along the San Diego County coast have been accompanied by improvements to San Elijo Lagoon and other wetlands it crosses.
Now such mitigation plans focus on improving habitat for native plants and wildlife, along with building amenities such as trails and bike lanes. Under Boerner Horvath’s bill, blue carbon would become another factor the Coastal Commission would evaluate.
“Her bill would add the carbon sequestration impact to the consideration of what mitigation we would require,” said Coastal Commission Legislative Director Sarah Christie, who noted that the commission has not taken a position on the bill.
The new rules would apply to any projects on public land, which might include marine projects such as offshore wind, offshore oil and gas platform decommissioning, underwater pipelines, cables, marinas, ports and docks, Christie said. Dredging, aquaculture operations and coastal bridge and roadwork could also fall under its provisions.
Officials with the San Diego Association of Governments, a regional planning agency, declined to comment, saying they were not familiar enough with the bill to say how it might affect ongoing transportation plans or other public works projects. Boerner Horvath and Christie said there isn’t an estimate now on how many projects the bill could affect or what the costs would be.
Boerner Horvath said the bill was inspired by the coastal geography of her district, as well as recent revelations about the role coastal habitat plays in the planet’s carbon balance.
“I’ve always been interested in blue carbon,” she said, “I think it’s a function of the district, which has so many lagoons.”
Boerner Horvath said as she learned about carbon sequestration she realized the opportunities in her own backyard.
“I learned that salt marshes sequester more carbon than trees,” she said. “I’m an environmentalist, I’m a mother, and I want to make sure there’s a healthy planet for my kids.”
Tidal marshes such as those found along the lagoons on San Diego County’s coast sequester carbon in deep layers of soil. These ecosystems capture carbon at a rate two to four times greater than tropical forests, according to the Blue Carbon Initiative, a coalition of international scientific and educational organizations. Seagrasses are submerged, deep-rooted meadows found on shorelines, which store twice as much carbon as terrestrial forests.