The City and County of San Francisco’s Approach to Sea Level Rise Science and Adaptation Planning: Creating Infrastructure Resilience from Information Chaos

Mr. David H Behar, San Francisco Public Utilities Commission and Practitioner Exchange for Effective Response to Sea Level Rise (PEERS), San Francisco, United States, W Tad Pfeffer, University of Colorado at Boulder, Boulder, CO, United States, Kris May, AECOM, Oakland, CA, United States, Philip Mote, Oregon State University, Corvallis, OR, United States and Daniel R Cayan, University of California San Diego, Scripps Institution of Oceanography, La Jolla, CA, United States
Abstract:
During one 17 month period ending October 2013, three major reports on sea level rise from three highly respected science providers produced three differing, in some cases wildly divergent, estimates of sea level rise through the year 2100. These reports, by the National Research Council, the IPCC, and the National Climate Assessment, collectively flummoxed the lay reader seeking direction on sea level rise projections to incorporate into adaptation planning. Guidance documents soon emerged from state entities, including regulatory agencies, which caused further confusion.

The City and County of San Francisco, surrounded by water on three sides, began developing City-wide sea level rise guidance in 2013. A Sea Level Rise Committee featuring representatives of key infrastructure managers met over a nine month period, and their work included an in-depth review of the science of sea level rise. To convert divergent scientific reports into “actionable science” required not only a close reading of each but extensive expert elicitation to tease out the meaning behind each of the numbers and the associated uncertainties. In the end, sufficient consistency between the differing projections, fortified by political exigencies, allowed a “scientific consensus” with actionable science value for the City to surface. The resulting document, “Guidance for Incorporating Sea Level Rise into Capital Planning in San Francisco,” begins by providing a scientific underpinning for planning, guidelines for incorporating uncertainty – particularly for accommodating multiple projections for any particular time slice – and outlines a four step process for assessment and adaptation. It also relies on new state-of-the-art inundation maps produced as part of the SFPUC’s capital improvement program. Together, the Guidance and associated tools provide a road map for successful assessment and adaptation to sea level rise. We will also draw lessons from the experience that may be of value to science leaders seeking to make contributions in the decision making domain.

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