Size (of sea level rise) matters


Text by Sarah Phelan.

The San Francisco Bay Conservation and Development Commission has released detailed color maps that show the low-lying areas around the Bay in danger of flooding from global-warming related sea level rise. And while the maps look awfully pretty, the impacts likely won’t be.

Using U.S. Geological Survey data, the maps show the extent of inundation on each section of shoreline and
and can be enlarged to show a pretty high-rez image.

You can see the impacts of a predicted 16-inch rise, (predicted in 40 yeas) on say, the Central Bay here, a 55-inch rise (predicted in 90 years,) and, perhaps most revealing of all, a composite of the two.

First used in a BCDC draft report, Living with a Rising Bay: Vulnerability and Adaptation in San Francisco Bay and on the Shoreline, released earlier this month, the maps show that 180,000 acres of shoreline are in danger of flooding by 2050, increasing to 213,000 acres by 2100.

“This means that 84 percent of the area that will be flooded in 90 years will already be under water in 40 years,” said BCDC’s executive director Will Travis in a press release. “Most of this area is low-lying flat land that was created when shallow parts of the Bay were reclaimed by land fill projects in the 19th and 20th centuries.”

Or as Leslie Lacko, the principal author of the BCDC sea level rise report on sea level rise, put it, “The areas that will be flooded by high tides at mid-century are already within the 100-year floodplain, where currently there’s a one percent chance of flooding every year. By 2050, the chance of flooding in the same area will be 100 percent every year.”