Sea levels are already rising along the San Francisco Bay and local creeks, and officials can't waste time in finding a fix, experts said at a June 19 conference to address the issue.
Sea-level changes caused by global warming could affect an estimated 270,000 people in the Bay Area and destroy $62 billion in shoreline development, said conference panelists at NASA Ames Research Center.
But many cities aren't on board with armoring their shorelines, they said. Because sea-level rise is perceived as a slow process, some agency and government officials think they have time to implement innovative tactics.
Not so, the experts said. And cities will need to spend millions of dollars on developing plans that won't exacerbate the situation.
The conference, which drew about 250 attendees, came three days after the release of a Santa Clara County civil grand jury report on sea-level rise. The report found that current flood-control systems are inadequate, and cities and the county are not on the same page in addressing sea-level rise.
The City of Palo Alto was not aware of projects in Mountain View and Sunnyvale to compensate for the hazards of a rising sea level, for example, and Milpitas is not addressing the issue at all, the grand jury noted.
California Assemblyman Rich Gordon and U.S. Rep. Anna Eshoo joined with NASA to present the conference.
"There has been an 8-inch rise over the last century, and there is an expected 3- to 4-foot rise over the next century," Eshoo said, referring to findings by the International Intergovernmental Panel on Climate Change (IPCC).
Gordon, who has led state-level efforts as chair of the Select Committee on Sea Level Rise and the California Economy, has authored legislation for a state-held repository of sea-level rise planning documents. He also helped secure funding last year for municipal planning.
Keynote speaker Gary Griggs, director of the University of California at Santa Cruz Institute of Marine Sciences, said carbon dioxide -- a primary culprit of rising temperatures, melting ice caps and sea-level rise -- is the highest in 400 million years, according to climate records taken from ice cores.
A study of temperatures over the last 130 years shows that carbon dioxide and temperature rise mirror each other, and sea levels also track the temperature elevations, Griggs said. About two-thirds of sea-level rise is from ice melt, he added.
If all of the ice in Greenland melts, sea levels would rise 25 feet; if all of Antarctica's ice melts, seas would rise 200 feet, he said.
Locally, sea levels by 2030 are predicted to rise between 6 inches to one foot; by 2050, the mid-projection is up to 2 feet. By 2100, the average expected is 3 feet and up to 5 1/2 feet, according to a 2012 study ("Surging Seas") by the nonprofit organization Climate Central, Griggs said.
"SFO starts to go under water with a 16-inch rise," he said.
NASA Ames Director Eugene Tu used the 200-acre NASA Center as an example of what can be expected. With a 4- to 5-foot average sea-level rise, roughly half of the property would be under water.
NASA Ames has already experienced flooding as a result of sea-level rise and storms. Areas of the property were flooded during the 1998 El Niño event, researchers said.
The real concern with sea-level rise would come with short-term events such as tsunamis, storm surges, and, along the San Francisco Bay and local creeks, king tides. A 37-inch sea-level rise by the end of the 21st century could result in a 14.8-foot water height during a 100-year flood, researchers said. About half of NASA's runway would be under water in a 100-year storm, for example, hampering rescue and relief efforts.
And much more than infrastructure is at risk. These assessments don't consider the health effects of sea-level rise and flooding, which could increase certain diseases, said Susan Stuart, health planner for Santa Clara County's Center for Chronic Disease and Injury Prevention.
Severe psychosocial stress and mental-health issues took years for people to get over after Hurricane Katrina, she said.
Sea-level rise will especially affect vulnerable populations such as the elderly, chronically ill, homeless and renters, she said. And current damage estimates also don't account for the health effects of flooding at contaminated hazardous-waste sites and wastewater-treatment plants in the Bay Area, she added.
Despite the grim picture that was painted at the conference, there are potential solutions to avert potential consequences.
Current shorelines will need higher levees and other shoreline protections, said Cristina Milesi, NASA-ECOCAST research scientist. NASA alone would need to raise its horizontal levees by 3 feet over 20 to 22 acres of wetlands.
Using sediments could help control the problem by expanding or raising marshes, which would help offset some of the water. Combined with current rates of natural sedimentation, additional sediments from other sources, such as bay dredging, could help build higher horizontal levees, researchers said.
But any approach must be regional to avoid disastrous conditions in another community, Larry Goldzband, executive director of San Francisco Bay Conservation and Development Commission (BCDC), said during a panel discussion on challenges and options in Santa Clara County and the region.
"Everything is networked. You can't get to BART or the airport if (U.S. Highway) 101 is under water," he said.
Goldzband estimated it would take $15 million over four years to develop a regional plan.
The process is complicated by the sheer complexity of organizing the 150 agencies with use of land along the bay and getting buy-in from multiple agencies, he said.
For example, marshes will change when seas rise, and that causes complications when trying to comply with the Endangered Species Act (ESA). A project that attempts to create habitat rather than maintaining existing habitat runs into barriers because the ESA says it can't be changed, said Len Materman, executive director of the San Francisquito Creek Joint Powers Authority.
But some cities and agencies are already taking on their own projects, including Mountain View, which has created a Shoreline Sea Level Rise study for the area bounded by U.S. Highway 101, the San Francisco Bay, Stevens Creek and San Antonio Road.
The city has developed 12 capital-improvement projects, including restoring wetland habitat and strengthening levees, said Lisa Au, city principal civil engineer.
Estimated costs are $40 million to $60 million, with about $20 million to $23 million being the city's responsibility and the remainder to be covered by regional agencies, Au said.
Mountain View's North Bayshore Precise Plan includes a 11.3-foot base flood elevation for construction and levee protection, she added.
Materman said his agency has developed the SAFER Bay Project. It is the largest multi-county sea-level rise project in the state. SAFER Bay will design and conduct environmental review of levees and new flood-mitigation facilities for Palo Alto, Menlo Park and East Palo Alto to protect the cities from a 100-year bay tide with 3 feet of sea-level rise. The San Francisquito Creek Joint Powers Authority is spearheading the $37 million San Francisquito Creek flood-control project.
Earlier this month Caltrans began construction on part of the San Francisquito Creek project, addressing bridging across U.S. Highway 101.
Palo Alto Councilman Greg Scharff said the conference has convinced him that the city needs to take another look at its shoreline plans while it looks to update its pending Sustainability and Climate Action Plan.
"There seems to be so much more we can do in light of what was said today," he said.