American Canyon wetlands talk highlights ecosystem's role in sequestering carbon, slowing sea level rise

AMERICAN CANYON — The Bay Area’s remaining wetlands in American Canyon and across the region are critical not only as a hot spot for ecological diversity and human well-being, but also as a complex ecosystem that can be adapted to address the myriad threats of climate change.

That is the message that an audience at the American Canyon Library received in a two-part presentation, hosted by local chapters of the Audubon Society and the Sierra Club, on Jan. 14.

The presentation highlighted both the role that the dizzying array of wetlands bird life plays in sustaining the Bay Area’s unique ecology, and how these wetlands can address the threat of sea level rise in the Bay Area.

“These wild places give us relaxation,” said Mark Stephenson, the president of the Napa-Solano Audubon Society, who hosted the first half the evening’s visual presentation. “They reduce our stress; it’s important for our souls.”

Stephenson entertained the audience with slides of his own photographs of the rich variety of birds, from the northern flicker (part of the woodpecker family) to the snowy egret, which can be found in American Canyon’s low-lying mudflats and tidal and seasonal wetlands.

Aside from their beguiling plumage and overall beauty, birds in the wetlands are a keystone species, holding the habitat together by keeping pests in check and distributing seeds that promote the ecosystem’s plant growth.

The Napa wetlands’ bird predators, to the surprise of the audience, also help the wine industry, according to Stephenson.

Ground-dwelling voles, Stephenson explained, destroy the roots of grapevines. So winemakers put in owl boxes to attract barn owls, which keep the vole populations in check.

“A pair of barn owls can eat 2,000 voles during the nesting season,” Stephenson said.

American Canyon’s wetlands feature diverse fauna beyond birds. Coyotes, foxes, deer and various rodent species, including the endemic salt marsh harvest mouse, are found in these habitats.

Yet American Canyon’s wetlands, according to Stephenson, face a persistent foe: unchecked development.

“One of the reasons that we are here tonight is because there are vineyards at the north end of the wetlands that they are planning to develop into warehouses,” he said.

While he insisted that he was not against all development, Stephenson emphasized that unregulated growth poses an existential threat to the few remaining wetland ecosystems in the Bay Area, which are critical habitat for wildlife but also essential for combating a growing threat to the region – sea level rise.

“They’re building right up to the edge of the grassland and sometimes into the marsh, and it’s not right because of sea level rise,” he said. “In a few years, they’re going to be in trouble.”

“It’s already happening in American Canyon; it’s happening in the Bay Area, and all over the world,” said Scott Thomason, who spoke about the threats of sea level rise in the Bay Area and the importance role that wetlands play in mitigating it.

Thomason, who is the treasurer of the Napa Sierra Group subgroup of the Sierra Club Redwood Chapter, was joined by Paulina Viera Zambrano, a student at Napa Valley College and a former Sierra Club intern.

Thomason explained that, while sea level rise has been occurring naturally since the end of the earth’s most recent ice age, human activity has accelerated it. The burning of fossil fuels releases greenhouse gases, which trap heat in the atmosphere and warm the planet. As a result, ice sheets and glaciers are melting at a historically rapid rate.

“When enough ice and glaciers melt, that raises the level of the ocean significantly,” said Thomason. “Our bay ecosystems are on the front lines of sea level rise, and are at risk.”

In addition to threatening ecosystems, sea level rise also threatens the public health of communities in industrialized areas.

“The San Francisco Bay has a strong history of industrial activity on the shore, which has left us with contaminants on the shoreline,” Thomason said. “As sea levels rise and inundate these sites, floodwaters can also transport toxins up to three miles from their source, which poses a great risk to overall community health.”

Groundwater can also pose a threat to the Bay Area as a result of rising sea levels, Thomason said. That is because when saltwater moves inland and underground, it pushes the freshwater up and into surface infrastructure.

Addressing threats of sea level rise to critical infrastructure, public health and the ecological health of the Bay Area requires a complex, multitiered approach.

Plan Bay Area 2050+ is the region’s ambitious plan to address climate change and sea level rise through sound transportation, housing, economic and environmental policies.

Part of this broader effort is the Regional Shoreline Adaptation Plan, which requires local governments in the Bay Area to develop their own local adaptation plans to address multiple sea level rise scenarios.

According to the Metropolitan Transportation Commission, the Bay Area’s transportation planning agency, the cost to adapt hundreds of miles of regional shoreline to protect against rising sea levels will run to about $96 billion.

RSAP plans range from nature-based solutions focused on adapting existing buffer ecosystems like beaches, reefs, and marshlands to hybrid natural and engineered efforts like undulating levees planted with native vegetation, which the East Bay city of Hayward has proposed.

Yet the RSAPs will not have to be submitted for approval until January 2034, which both audience members and the event’s organizers fear is too late.

More reason, Thomason said, for what’s left of the Bay Area’s wetlands to be front and center for the region’s resiliency plans. Not only do wetlands serve as buffers for rising sea levels, but they also play a role in addressing the root accelerators of climate change.

Wetlands are a marvel of natural eco-engineering; they sequester more carbon than even the rainforests of the Amazon. Carbon sequestration occurs when atmospheric carbon dioxide is captured and stored in soil and plant life. Because they are oxygen-poor and waterlogged, wetlands can dramatically slow down the decomposition of organic matter, storing carbon for thousands of years in the form of peat and soils rich in organic material.

During the evening’s Q&A session, both audience members and organizers noted that those in attendance were mostly older, and therefore not likely to live through the worst effects of climate change this century.

“People figure, ‘If it’s going to happen 20 or 40 years from now, what do I care?’” said Angie Brooks, a Vallejo resident who attended the presentation and spoke to the Napa Valley Register. “Nobody cares, and they don’t want to care. They don’t want to do anything about it, and they figure they can’t do anything about it.”

That’s a cause for concern for Viera Zambrano, the NVC student and the sea level rise talk’s co-speaker.

“It’s scary to think that I am going to have to live through that,” she said in a conversation with the Register. “My children – if I do decide to have children – are going to have to live through that.”

“Right now, we are at the 20-year window where sea level rise is slow, but then it’s going to come fast,” she said.

Viera Zambrano said it is often challenging to get both her friends and peers to take the threat of climate change seriously. “I do see a lot of indifference and a bit of ignorance,” she acknowledged.

Many of her peers, she noted, express a resigned fatalism in the face of climate change, believing that there is little to be done and that older generations who will not live through the consequences continue to hijack systemic change to address it.

Nonetheless, Viera Zambrano has participated in educational campaigns in public schools and has noted that younger students, particularly elementary school-aged children, are more receptive to taking climate action.

“Little kids are so receptive to this because they are naturally very curious,” she said. “And what draws them in is that curiosity.”

As a Sierra Club intern, Viera Zambrano has used the vulnerability and resilience of endangered species like the monarch butterfly as an accessible analogy for youth to learn about the broader issue of climate change.

“My own love for the environment, nature and wildlife started when I was a little girl,” she said. “So why not work with the younger generation?”

The Napa Sierra Club runs a mentor-guided student internship program, which empowers high school students to work on a multitude of local environmental projects to help address climate change through community and public education.