San Francisco Bay wetlands may face losing battle against sea level rise

Elaine Bible in PhysOrg: San Francisco Bay's tidal marshes may face a grave threat from sea level rise in the next century, according to a new study published by a group of scientists, including Professor of Biology Tom Parker.

Tidal salt marshes form on the fringes of the Bay. Tall, reed-like cordgrass grows in lower marshes, inundated by the tide twice a day, while salt-resistant succulents are the signature plants of higher marshes, which only get wet during extreme high tides and storms.
These ecosystems are a critical natural resource. They sustain migrating birds and other wildlife, protect coastlines against flooding, provide nursery areas for commercial fisheries and filter pollutants from seawater and the atmosphere.

But the survival of these wetlands depends on a delicate equilibrium between the water level and how quickly sediment is deposited by the seawater. That balance is likely to be thrown off course by climate change over the next century, the researchers found, as accelerated sea level rise outpaces the marshes' ability to build up layers of organic matter, mud and minerals.

The researchers found that in the worst case scenario, 93 percent of the Bay’s tidal marsh could be lost in the next 50-100 years if no significant marsh restoration efforts are undertaken. This dire prediction was based on a sea level rise of 5.4 feet and low sediment availability.

"So far, wetlands in San Francisco Bay have been able to keep up with low rates of sea level rise of about 1 millimeter per year, which have increased to 2-3 millimeters per year in the last decade," Parker said. "But the sea level rise predicted for the next century is far greater and the bottom line is that there won't be many wetlands left."...

A salt marsh near Hayward Shoreline Interpretive Center building, adjacent to highway 92, Hayward, California, shot by Mercurywoodrose, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Bleak future for Bay area tidal marshes?

Terra Daily via SPX: A new study, led by PRBO Conservation Science (PRBO), projects a bleak future for San Francisco Bay's tidal marshes under high-end sea-level rise scenarios that are increasingly likely. PRBO and colleagues found that in the worst case scenario 93% of San Francisco Bay's tidal marsh could be lost in the next 50-100 years [with 5.4 feet or 1.65 meters of sea-level rise, low sediment availability and no significant restoration].

PRBO's study indicates, however, that not all marshes will be lost and that society's actions today, including restoration currently underway, can keep more marshes intact as sea levels rise.

This first-of-its-kind study assesses how sea-level rise, suspended sediment availability, salinity and other factors might impact San Francisco Bay's tidal marshes. The study, which considered multiple scenarios to project possible future outcomes, was authored by researchers from PRBO as well as ESA PWA, University of San Francisco, UC Berkeley, and San Francisco State University.

Tidal marshes are vital to migratory birds, commercial fisheries, other wildlife and people. Marshes act like giant sponges, protecting highways, businesses, homes and other structures by reducing flood impacts in large storm events and as sea levels rise. Tidal marshes also filter out pollutants and sequester carbon.

"Tidal marshes are incredibly resilient to changes in sea level, depending on how fast seas rise and how much sediment is available. Unfortunately, marshes cannot keep up with the high-end sea-level rise predictions on their own. They will need our help." said Diana Stralberg, the study lead author of PRBO and the University of Alberta...

Shortly after dawn at Charleston Slough, Palo Alto Baylands, California, shot by Ingrid Taylar, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license

Climate change effect on San Francisco Bay and Delta detailed in new study

Mike Taugher in the San Jose Mercury News via the Contra Costa Times: California's water problems and the ecological pressure on the West Coast's largest estuary will intensify in a warming world, according to a first-of-its-kind scientific study.

San Francisco Bay and the Delta will get warmer, saltier and clearer if global warming continues over the next several decades. That will increase the risk of extinction for some kinds of fish and could help unwanted species, including a toxic algae, flourish Flooding is likely to be more common upstream and along the coast, and water supplies will be stretched due to a shrinking snowpack, the researchers found.

In the Delta, already seeing a broad ecological decline, the probability of further ecological surprises will increase. "We're going to enter a new era of environmental conditions," said James Cloern, the study's lead author and a phytoplankton ecologist at the U.S. Geological Survey in Menlo Park.

Cloern said the seven-year study was the most complex research project he's undertaken in 36 years at the USGS. The researchers said their paper appears to be the first multifaceted assessment of how the estuary could respond to climate change.

...The researchers took two climate change scenarios they considered reasonably likely and projected what would happen to the estuary given the way it is managed now for wildlife and water supplies. In the first scenario, greenhouse gas emissions would be curbed in the coming decades, and the climate would turn out to be only moderately sensitive to the gases. In the second, bleaker, scenario, greenhouse gas emissions would continue to increase, and climate would react strongly to them....

NASA image of San Francisco Bay

Bay Area adopts historic climate-change rules

John Upton in the Bay Citizen (San Francisco) has more on the new coastal development regulations in the Bay area: New developments on the shores of San Francisco Bay won't be approved unless they offer economic or environmental benefits that outweigh the cost of protecting against rising seas, under rules adopted Thursday by regional leaders.

The new rules, written to reduce the risk of flooding as the climate changes, are the most advanced and detailed of their kind in the nation. “What we’re doing today goes beyond the Bay Area,” San Francisco Bay Conservation and Development Commission Chairman Sean Randolph said before joining in a unanimous vote to approve the guidelines. “It has national significance.”

But the guidelines are significantly less ambitious than a proposal to discourage all waterfront construction that the commission, which has jurisdiction over the shoreline, initially planned.

...“We believe that the version adopted today removed the impediments to proactive collaboration on sea-level rise,” DMB Associates Vice President David Smith said. “Our concerns with the earlier versions of the amendments were that they established prohibitions and presumptions that would have thwarted solutions.” Smith says the Redwood City project could benefit its neighbors by encouraging the development of a levee system to protect the area from flooding, for example.

...“These policies discourage projects that would develop in dumb places, and it encourages tidal marsh restoration in undeveloped areas,” said David Lewis, executive director of the nonprofit Save the Bay. “That’s what the original draft of the policies was calling for.”...

San Francisco at night, shot from Treasure Island by Bsteckler, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

San Francisco Bay conservation board approves sea level development plan

J.K. Dineen in the San Francisco Business Times: The San Francisco Bay Conservation and Development Commission has unanimously adopted new land-use guidelines for development projects in low-lying areas, making the Bay Area the first region in California to lay out a plan for sea level rise.

In a 24-0 vote the BCDC amended its guiding Bay Plan document with new language on climate change in the Bay Area. The new plan requires public agencies or private developers to do a cost-benefit analysis of building in low-lying areas and to submit a plan to cope with sea level rise and other climate change eventualities. While the BCDC has jurisdiction over permitting of development projects within 100 feet of the Bay shoreline, the new Bay Plan amendment guidelines are meant to influence decision-making affecting a much larger area—180,000 acres potentially vulnerable to predicted sea level rise by mid-century.

The final plan came after two years of contentious debate between environmentalist groups fighting to protect wetlands by restricting development in low-lying areas and builders who fought against overly restrictive guidelines that they said would kill much of the region’s transit oriented, infill development. In the end the a plan was reached that was supported by developers, trades unions and environmentalists...

Belvedere around the San Francisco Yacht Club, shot by Mbz1, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Developers withdraw opposition to Bay Area planning document that takes sea level rise into account

Julia Scott in the Bay Area News (San Francisco): The Bay Area's most powerful developers, trades councils and chambers of commerce have withdrawn their opposition to a planning document that makes sea level rise part of the approval process for new development at the edges of San Francisco Bay.

The Bay Conservation and Development Commission will discuss the draft Bay Plan Amendment concerning climate change -- the region's first effort to codify the long-term threat of sea level rise as a factor in the development of low-lying areas that surround the bay -- at its meeting Sept. 1.

Despite the announcement that groups like the Bay Planning Coalition and the Bay Area Council are withdrawing opposition, several city officials still have problems with the fact that the BCDC, which normally just regulates public access, is taking on the role of land use arbiter. San Jose Mayor Chuck Reed sent in a letter of objection, and officials in Martinez, Fairfield and Suisun City continue to oppose the amendment.

….BCDC Executive Officer Will Travis said his agency's goals and jurisdiction have been "deeply misunderstood." The commission only has power to deny projects within a 100-foot shoreline band around the bay, and it cannot deny a proposalvbased on whether it adequately addresses the impacts of sea level rise or flooding.

"The logic has been, 'We can't afford to deal with the problem and, therefore, the problem can't exist.' We realize it takes a long time to get an awareness of why these changes are necessary. We're in the first stages of that," said Travis. The Bay Plan Amendment requires projects to submit a risk assessment that takes into account both flood risk and sea level rise, and have a plan to cope with all eventualities…

The Golden Gate Bridge shot by Mila Zinkova, who photographs more than polar scenes. Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Environmentalists, developers clash over how to deal with San Francisco's rising tide

Alastair Bland in the San Francisco Examiner: As weather patterns take unprecedented turns and polar bears step through soft spots in the sea ice, the subject of climate change continues to generate quarrels. At the federal level, hot air howls among lawmakers, who bicker over emission-reduction goals of the distant future, while a few media pundits still reject the notion that the world is changing.

But in the Bay Area, officials are already preparing for global warming by rewriting local building policies in anticipation of rising sea levels. The San Francisco Bay Conservation and Development Commission, a 27-member state agency that regulates activities that affect the waters and shoreline of San Francisco Bay, is in the process of crafting regulatory guidelines that could restrict new development projects in parts of the Bay Area threatened by rising waters.

While environmentalists see these measures as wise, some developers contend that the BCDC is being overly precautionary and will unnecessarily stifle employment opportunities for contractors and builders.

The BCDC’s proposed guideline suggests “that state agencies should generally not plan, develop, or build any new significant structure in a place where that structure will require significant protection from sea-level rise.” If one prediction — produced by the United Nations — of a 55-inch rise in sea level by 2100 proves true, the BCDC’s advisory could apply to 332 square miles of Bay Area real estate. This 213,000-acre region is home now to 270,000 people, and state officials believe that figure should grow no larger.

...But critics of the BCDC’s process have argued that the commission is basing policy-making on faulty maps that show ominous future high-tide lines drawn without regard to existing flood protections. These maps, critics argue, could drive down property values and scare away insurers from real estate where the waters may never reach...

San Francisco coast in 1982, shot from Communi core by S.Fujioka, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Planning for sea-level rise in San Francisco Bay raises eyebrows

Jeff Quackenbush in the North Bay Business Journal (California): A regional agency tasked with managing environmental restoration and the built environment along the San Francisco Bay shoreline plans to adopt an updated sea-level-rise forecast this fall, but some agriculture and construction groups are concerned those predictions jeopardize major tourism and commerce thoroughfares as well as their properties.

With relatively little public notice, four Bay Area regional bureaucracies, the Association of Bay Area Governments, the Metropolitan Transportation Commission, the Bay Area Air Quality Management District and the Bay Conservation and Development Commission have come together under the Orwellian sounding OneBayArea.org. [read more]

The San Francisco Bay Conservation and Development Commission, a state body made up of representatives from county governments ringing the Bay, in early 2009 floated an amendment to the San Francisco Bay Plan that would update two-decade-old sea-level predictions to account for estimates of ice cap and glacier melting blamed on human activities.

The Bay is forecast to rise 11 to 18 inches by 2050 and 23 to 55 inches by 2100, according to commission staff. In early May, a group called San Francisco Planning and Urban Research Association, or SPUR, released recommendations for government agencies to deal with what the group calls unavoidable sea-level rise from climate change. Based on new BCDC sea-level rise forecast maps, the group estimated 99 miles of major Bay Area roads and highways could be flooded from a 16-inch rise, and 186 miles from a 55-inch rise. Affected could be interstates 680 and 880 plus highways 12, 37 and 101. SPUR said Highway 37 should be rerouted via Highway 121.

… Some winery owners in the Carneros region straddling Highway 121 between Sonoma and Napa counties also are concerned. Ceja Vineyards President Amelia Ceja said that many of the visitors to the property historically have come north through from San Francisco via highways 101, 37 and 121. Napa Valley Vintners is preparing a comment on the amendment, according to Rex Stults, industry relations director….

San Francisco Bay salt ponds, shot by Grombo, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Report offers strategies for San Francisco Bay to adapt

Kelly Zito in the San Francisco Chronicle: The Bay Area must start prepping for the whens, not the ifs, of climate change - like building cooling centers for use during heat waves, propping up homes on stilts in flood-prone areas and even abandoning roadways vulnerable to sea-level rise, according to an influential urban policy organization.

In a dramatic new tack that emphasizes adaptation over prevention, the San Francisco Planning and Urban Research Association is recommending in a report to be released today that officials in the nine-county region begin making concrete plans for the economic, environmental and public health impacts of increasing temperatures, more volatile weather, scarcer freshwater, rising seas and poorer air quality over the next 100 years.

…Today's 21-page report, titled "Climate Change Hits Home," states that reducing greenhouse gas emissions remains crucial. But with something like 45 billion tons of carbon dioxide still spewing into the global atmosphere each year, even the worst-case forecasts for changing climate patterns look optimistic. Against that backdrop, the planning group outlined 30 different strategies for dealing with impacts on public health, transportation, ecosystems, energy, water and sea-level rise in the Bay Area.

Some of the tactics are relatively uncomplicated - like setting up fans and misters at community centers during hot spells or installing light-colored concrete in public structures rather than heat-absorbing black. But others pose tricky logistical, financial and political questions. The problems associated with sea-level rise along San Francisco Bay's 1,000 miles of shoreline are among the thorniest.

Protecting coast-side homes, businesses, critical infrastructure and natural resources will clearly warrant multibillion-dollar investments in levees, coastal armoring or elaborate retrofitting with stilts or other equipment, Metcalf said. But in certain instances, it may be more cost-effective to simply cede man-made structures to the elements. One example mentioned is Highway 37, a 21-mile thoroughfare perched at the northern edge of San Pablo Bay. If sea levels do indeed rise by the projected 55-inch maximum over the next 90 years, transit authorities might consider abandoning the route and shifting traffic to Highway 121 to the north, the paper argued….

Highway 37 at sunset, very low to the water, shot by Aztecrosales, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Warming threatens state's coast, scientists say

David Perlman in the San Francisco Chronicle: Northern California's two great marine sanctuaries and nearby coastal regions will be severely threatened by the planet's changing climate over the next several decades as the sea level rises, the ocean water warms, marine animals migrate and coastal storms and erosion intensify, a panel of scientists warned Thursday.

The scientists, who have been studying the issue for the past two years, said in a report that sea level at the mouth of San Francisco Bay has already risen nearly 8 inches in the past century and noted that the most recent estimates of global warming's impact on the ocean off the California coast indicate a sea level rise of 29 inches in the next 40 years and 75 inches by the end of the century.

"The effects of this rise will play out everywhere," said John Largier, a UC Davis oceanographer and chairman of a scientific advisory council that prepared the report for the Gulf of the Farallones and Cordell Bank national marine sanctuaries.

Some ocean species are already adapting to warming waters off the coast by moving northward, the scientists found. For example, gray whales, which normally give birth in the warm lagoons of Baja California, are beginning to move calving grounds northward. Some whales have been observed giving birth as far north as the waters off Monterey County, the scientists noted.

"There is more and more evidence of rapid adaption by marine life to changes in the climate so far," Largier said, "but as changes grow greater, adaptation will end, and how much we will lose along the way we can't predict precisely."….

3-D perspective image of the San Francisco Bay Area from NASA's Shuttle Radar Topography Mission (SRTM)