News In Numbers: Mapping Tools Let You Visualize Future Flooding In San Diego
For this week’s look into public data, we thought we’d post some interesting tools created by the scientists and mapmakers at Climate Central, an independent, nonprofit research organization. With their maps you can choose a location and dial up the sea level rise to see what might be submerged. This hasn’t been available before.
There is a lot here and you won’t exhaust it in 5 minutes. The group’s first foray was the Risk Zone map. There you can choose so many feet or meters of sea level rise, and see the resulting number of residents expected to be flooded, plus their income and other demographics.
Next Climate Central produced the Risk Finder. This lets you tally the value of property at risk and generate reports based on legislative, U.S. congressional district or even county supervisor district. An elected representative could see, for example, what part of a district would be underwater if sea level rose 3 feet. You can check out the ZIP code with the most people exposed to a rising sea. In San Diego that’s 92109, Mission Beach and Pacific Beach, with 2,608 people living below 3 feet elevation.
More sophisticated users can choose which data sits behind the map: National Research Council, National Climate Assessment, IPCC and others.
Dan Cayan, a researcher at Scripps Institution of Oceanography, calls the maps useful. But he also cautions they are bathtub models, when the ocean is not really a bathtub. Storms and king tides are usually what bring the highest seas.
The most recent tools Climate Central has released are Mapping Choices and Seeing Choices. These are intended to drive home the point that the fuel we burn and the methane we release today will have their largest effect long after the present adult generations are gone. The map at the top of this story was made with Mapping Choices. It shows divergent futures – both more than seven generations from now – one based on dramatic changes in how we travel and get our energy, and one with business as usual. Carbon we emit now will stay in the oceans for hundreds of years.
The local picture
For more than two decades sea levels in Southern California were stagnant, Cayan said. “But Southern California sea levels rose significantly,” about 2-12 inches, during the the exceptionally warm water associated with the recent el niño. “The La Jolla tide gauge station recorded its highest-ever sea level” in November 2015 when a moderate storm coincided with an astronomical high tide. Though el niño has faded, and sea levels with it, Cayan said, they are still running above tide predictions.
San Diego can expect to see many more such incidents of extreme high sea level, research says. One California model in the National Research Council 2012 paper on West Coast sea level rise estimates that extreme high sea conditions that occur on average 9 hours per decade now could rise to 250 hours per decade by mid-century.
Almost five years ago experts took a look at how homes, roadways, sewers and ecosystems along San Diego Bay would fare with higher sea levels. Few assets were seriously at risk in the early climate change years, which includes the present. But that risk compounded between 2050 and 2100 as sea levels rise possibly 4 or 5 feet and climate changes “move outside the ranges of past human experiences,” as the National Research Council put it.
And if the massive ice now held on western Antarctica breaks up and slides into the ocean faster rather than slower, which scientists have observed recently, then dramatic sea level rise could come much sooner.
For a different perspective on flooding in the region, we’re also posting the flood maps of the Federal Emergency Management Agency. Areas in purple are those where property owners are required to carry flood insurance.