Sea-level rise could worsen current San Francisco Bay Space inequities — ScienceDaily

Rather than waiting for certainty in projections of sea level rise, policymakers can now plan for future coastal flooding by addressing existing inequalities among the most vulnerable communities in floodplains, according to Stanford research.

Using a methodology that includes socio-economic data on neighborhood groups of approximately 1,500 people, scientists found that several coastal communities in San Mateo County, California – including half of households in East Palo Alto – are at risk of financial instability or flooding due to existing social factors expected by 2060. Even with flood insurance coverage, these residents would not be able to pay for any damage caused by flooding, which could lead to homelessness or bankruptcy of people, which are essential to the diversity and economic functioning of urban areas. The paper was published in Earth’s Future magazine on July 12th.

“These are workers who run a city, they are the heart and soul of an urban corporation. If you move a significant majority too far outside of the urban area, the functionality of that city crumbles,” said senior co-author Jenny Suckale, assistant professor in geophysics from the Stanford School of Earth, Energy & Environmental Sciences (Stanford Earth). “How can we ensure that we provide these communities with a future that is not linked to their decline?”

Estimates of flood damage are usually calculated by civil engineers in the form of monetary damage to structures. With their new model called the Stanford Urban Risk Framework (SURF), the researchers are taking a people-centered approach to risk assessment that focuses on those residents who are most likely to lose their livelihood when water floods their homes. While every household in the planned floodplain will be burdened by flood damage, the socio-economic context determines how damaging the costs will be. In several San Mateo County’s coastal communities, more than 50 percent of households will face financial instability.

“If you just look at the dollar amount, you are missing a major component of the problem,” Suckale said. “What could be a nuisance in some churches changes life in other churches – it’s really about being close to a turning point.”

Researchers identified which communities are near a fiscal tipping point by calculating their social risk or financial instability, a metric intended to complement existing assessments of monetary risk through hazard. They overlaid coastal flood maps and building footprints with structural information, took into account projected annual damage from sea level rise and estimated household incomes based on labor and economic data to calculate losses based on census block groups – geographic units used by the U.S. Census Bureau publishes demographic Estimates.

“It was surprising to see in the data how many more households with lower incomes relative to their incomes were affected and how unsustainable it is for these types of households to bear these costs,” said lead author of the study, Avery Bick, a PhD student at the Norwegian Institute for Natural Research who worked on the project as a PhD student at Stanford.

Despite the uncertainty about the extent of future climate change, researchers agree that rising sea levels will exacerbate coastal flooding – a threat that residents from Foster City to East Palo Alto have faced for decades. Many of the highest social risk neighborhoods are made up of single parent households and are more racially diverse than the San Mateo County’s average, according to the study.

“Climate change doesn’t just mean it’s getting hotter or sea levels are rising – it will literally change the fabric of society, especially if we continue to ignore it,” Bick said. “It gave me a sense of how vulnerable the social fabric is to change and how we need to be proactive. Otherwise, it will change in favor of those with more resources.”

Researchers worked with local stakeholders to develop an equitable approach to planning to adjust sea level rise. Through conversations with organizations such as the San Mateo County Office of Sustainability and the US Army Corps of Engineers, as well as community-based groups such as Climate Resilient Communities, El Concilio, and the North Fair Oaks Community Alliance, they learned that what the climate lacks in the discourse was framing the dollar amount of damage in relation to what people can pay for. The team’s approach has involved a shift in awareness, from the amount of money you lose to the value of goods and services you can no longer buy due to the disaster, said Derek Ouyang, co-author of the study, a lecturer in geophysics at Stanford Earth.

“Any investment now can be directly tied to the resilience that prepares communities for future climate threats, whatever they are,” Ouyang said.

Because San Mateo County’s population is both very affluent and low-income, the average cost of flooding versus incomes at the county level “makes it look like you don’t have a big problem,” Suckale said. However, by assessing the impact on a smaller scale, the researchers were able to highlight the problem areas in a way that is more directly useful to policy makers.

The co-authors hope that this new quantitative method can be used to assess social risk on a scale of census blocks in other coastal flood-prone regions or to understand various climate threats from an equitable perspective.

“I think it’s useful to have a social risk metric that makes the actual risk completely independent because then we can simply improve the household’s ability to absorb the disorder, no matter what it is,” Suckale said.

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Materials provided by Stanford University. Originally written by Danielle Torrent Tucker. Note: The content can be edited in terms of style and length.