T67 Sea-Level Changes from Minutes to Millennia

Sunday, 19 October 2014
1:00 PM - 5:00 PM
306

TOWARD A MORE AQUATIC FUTURE: RISING SEAS AND COASTAL STORMS IN NEW YORK CITY

Paper number: T67-5
Program: Technical Sessions
Time: 1:50 PM – 2:05 PM

Authors

  • Vivien Gornitz Presenting Author
    Columbia University/NASA Goddard Institute for Space Studies, New York, NY
  • Radley Horton
    Columbia University/ NASA Goddard Institute for Space Studies, New York, NY
  • D.a. Bader
    Columbia University, New York, NY
  • C. Little
    Princeton University, Princeton, NJ
  • Cynthia Rosenzweig
    Columbia University/NASA Goddard Institute for Space Studies, New York, NY

Abstract

Following Hurricane Sandy (October 2012), New York City launched the Special Initiative for Rebuilding and Resiliency (SIRR) program to protect against current and future climate hazards. In support of this work, the New York City Panel on Climate Change (NPCC) developed a new methodology for projecting future sea level rise tailored to localized conditions, up to the year 2100, in order to provide decision-makers with updated climate risk information to safeguard coastal residents and critical infrastructure.

Sea level rise (SLR) components include global thermal expansion and local dynamic ocean heights from AR5 IPCC 2013 CMIP5 RCP4.5 and 8.5 data, revised estimates of ice mass loss from glaciers and ice sheets, gravitational/rotational/isostatic “fingerprints”, glacial isostatic adjustments, and land water storage. The projections simulate future sea level for three time slices, using two representative concentration pathways and 24 GCM models. The SLR projections, closely linked to hydrodynamic surge models, yield improved estimates of future coastal flooding probabilities. Sea levels at the Battery, lower Manhattan could reach 20 and 76 cm by the 2050s, and 33 and 147 cm by the 2080s for the 10th and 90th percentiles, respectively. Assuming no change in storm characteristics, higher sea levels would sharply increase the frequency and intensity of coastal flooding. Flood heights for the 100-year storm (stillwater) would rise from 3.4 m in the 2000s to 3.8-4.9 m by the 2080s (10-90 percentile), above NAVD88. The annual chance of today’s 100-year flood would increase from 1 to 1.7-12.7 percent by the 2080s. Future sea levels would significantly increase the area potentially at risk to flooding.

Providing planners with a broad range of science-based potential outcomes informs decision-making on different types of climate change adaptation, including infrastructure, taking into account adaptation lifetime and uncertainty estimates.