State Assembly bill could add ‘blue carbon’ step to development process in La Jolla

Kendall-Frost Mission Bay Marsh Reserve
Sites such as the Kendall-Frost Mission Bay Marsh Reserve on the northern edge of Mission Bay contain habitats such as salt marshes that sequester carbon from the atmosphere.
(Nelvin C. Cepeda / The San Diego Union-Tribune)

Some applicants would have to build or contribute to a project that supports coastal plants that sequester carbon from the atmosphere.


A new state Assembly bill making its way through the legislative chain could affect development on La Jolla’s coast by adding a new requirement to the permitting process.

AB 45, introduced in December by Assemblywoman Tasha Boerner Horvath (D-Encinitas), whose District 77 includes La Jolla, would require an applicant with a project that affects coastal wetland, subtidal, intertidal or marine habitats or ecosystems to build or contribute to a “blue carbon” project as part of the permitting process.

Boerner Horvath’s field representative Mariah Kallhoff told the Bird Rock Community Council during its Feb. 7 meeting that more details will be available in coming months about how that plan would be executed.

Blue carbon “is basically photosynthesis underwater,” Kallhoff said. “It is the carbon sequestration process that trees do above water. ... That is going to help us get to our carbon net zero goals that the state has, through the protection of blue carbon plants. Most of the time it is kelp, but [also] other species of plants that emit blue carbon, and we are trying to expand the blue carbon projects we have across the coast with this bill.”

The bill also would amend a section of the California Public Resources Code relating to coastal resources and require that “new development in the coastal zone comply with specified requirements, including, among other things, [those] intended to minimize energy consumption and vehicle miles traveled and, where appropriate, protect special communities and neighborhoods that, because of their unique characteristics, are popular visitor destination points for recreational uses. This bill would additionally require that new development minimize greenhouse gas emissions.”

In 2020, Gov. Gavin Newsom signed an executive order directing the California Natural Resources Agency, in consultation with other state agencies, to develop a Natural and Working Lands Climate Smart Strategy to serve as a framework to advance the state’s carbon neutrality goal and build climate resilience.

The order also set a goal to conserve at least 30 percent of state land and coastal waters by 2030. According to the Natural Resources Agency, a conservation area defined under the “30x30” plan is “land and coastal water ... durably protected and managed to sustain functional ecosystems, both intact and restored, and the diversity of life that they support.”

A recent Natural Resources Agency report on implementation cited a need to restore degraded coastal habitats to help capture carbon and mitigate climate change.

AB 45 is intended to help meet those goals, Kallhoff said.

Matthew Costa, a postdoctoral scholar at the Scripps Institution of Oceanography in La Jolla, said California has coastal “blue carbon ecosystems” with plants that sequester carbon from the atmosphere, such as seagrass beds and salt marshes, that are in need of protecting.

“The plants in those ecosystems take in carbon dioxide and turn it into organic carbon,” he said. “Some of that gets trapped in the sediment of those ecosystems and other organic matter that drifts in and … keeps it from going back into the atmosphere. It’s like a sink in that more carbon goes in than comes out.”

He said kelp beds — such as the ones off La Jolla — “probably contribute, but it is more complicated because the kelp produces a lot of organic matter but it goes somewhere else.”

“It doesn’t help us to move too slowly in this regard, so supporting these projects is a good thing,” Costa said.

However, he said, “the No. 1 thing we can do is keep what we can in the ground and restore beyond what we have. There is this idea that … if we disrupt a wetland somewhere and replace it elsewhere that we are creating parity, but that idea is flawed. You can’t get back what you lost. A coastal wetland builds up carbon slowly over time, a millimeter [a year] or so. So if you dig up a meter, that’s 1,000 years of carbon storage. If even half of that gets released … it could take hundreds of years to get the sequestration back.”

According to the bill, a blue carbon demonstration project that restores habitats or ecosystems that can take up and sequester carbon is limited to:

  • Ecologically appropriate locations where the habitat or ecosystem had historically occurred and subsequently became degraded or removed
  • The restoration of the habitat or ecosystem to its historical state, to the extent feasible
  • The use of diverse native species

The bill is being circulated to appropriate committees for review and edits. ◆