Creating 700 Acres of New Marshland Key to City’s Climate Action Plan

Salt marsh habitat removes carbon from the air, fights sea level rise by acting as coastal sponge.

This David Garrick-penned story originally appeared in the San Diego Union-Tribune on Aug. 23, 2022. It is reproduced here for the convenience of ReWild Mission Bay supporters and advocates.

The revised and more aggressive climate action plan San Diego adopted in Aug. 2022 commits officials to creating 700 acres of marshland across the city, more than triple the 220 acres of new marshland Mayor Todd Gloria had previously promised in northeastern Mission Bay.

The revised climate action plan prioritizes new marsh areas — sometimes called wetlands — because they serve the dual purpose of removing greenhouse gases like carbon dioxide from the air and fighting sea-level rise by acting as a coastal sponge.

Other elements of the revised plan, such as banning natural gas in new homes and getting more people to commute by transit and bicycle, would soften a negative impact on the climate by reducing carbon output.

In contrast, creating wetlands goes beyond softening a negative impact and makes a positive impact by taking carbon dioxide out of the air.

“The city emphasized a lot of the other components of the climate action plan that are noteworthy, but habitats are the only thing that goes carbon-negative — not just lowering our emissions but sucking up more emissions than they release — and tidal wetland habitats are one of the most efficient habitats in the world at sequestering carbon,” said Andrew Meyer of the Audubon Society.

Adding 700 acres of marshland will change the look and feel of San Diego in several places, particularly Mission Bay, which was entirely marshland until dredging after World War II transformed it into what city officials call the world’s largest aquatic park.

The revised climate action plan doesn’t specify where the 700 acres of new marshland would be created but commits the city to creating that amount of marshland. Mayor Gloria has committed to unveiling a full implementation plan by Feb. 2023.

Earlier in 2022, the mayor unveiled a plan to transform the abandoned De Anza mobile home park and some nearby land in the northeastern corner of Mission Bay into 221 acres of marshland. It will connect to the 40-acre Kendall Frost Marsh near Crown Point, the area’s last remaining natural marsh

The revised climate action plan would go beyond that to create 350 total acres of marshland by 2030 and 700 total acres by 2035.

Meyer said likely locations for additional new marshland include the Los Peñasquitos Lagoon in the Torrey Pines Natural Reserve and several other areas of Mission Bay: Tecolote Creek, Cudahy Creek and parts of Fiesta Island.

Other potential areas for new marshland are along San Diego Bay, which is controlled by the Port of San Diego. The port has previously restored marshland near where the Otay River enters San Diego Bay.

Creating marshland wasn’t included as a strategy in the city’s initial climate action plan approved in 2015 because scientific understanding of marshland hadn’t progressed far enough.

“The information on how much carbon wetlands store is pretty new,” Meyer said. “It wasn’t in the plan seven years ago because the science hadn’t gotten that far.”

Nicole Capretz, the lead author of the city’s 2015 plan and the executive director of the non-profit Climate Action Campaign, praised San Diego for embracing a new approach to fighting climate change that serves a dual purpose.

“Adding natural solutions to the climate action plan update is fantastic,” Capretz said. “We need to deploy solutions from every corner of our community, and wetlands will play a key role in both storing carbon and minimizing dangerous flooding.”

Marshland fights sea-level rise by acting as a sponge for excessive water during unusually high tides and storm surges, Meyer said. Having marshland along the coast also makes more sense than housing, which is much more costly to replace, he said. “Wetlands both mitigate climate change by sequestering carbon and help us adapt to climate change by helping with sea-level rise.”

Meyer added that local environmental advocates will need to continually lobby the city to stay committed to the 700-acre marshland goal.

“Seven hundred is a big number,” he said. “It will take some effort to push the city.”

The proposed marshland restoration would cost many millions, but city officials said they expect to obtain significant federal and state funding devoted to climate change and infrastructure.

Read the original story in the San Diego Union-Tribune.

Photos courtesy of Greg Hoxsie