• Source: Cal-Adapt. Data: Hourly Sea Level Projections generated for California's Fourth Climate Change Assessment (Scripps Institution of Oceanography).
  • Four models have been selected by California’s Climate Action Team Research Working Group as priority models for research contributing to California’s Fourth Climate Change Assessment. Projected future climate from these four models can be described as producing:
    • A warm/dry simulation (HadGEM2-ES)
    • A cooler/wetter simulation (CNRM-CM5)
    • An average simulation (CanESM2)
    • The model simulation that is most unlike the first three for the best coverage of different possibilities (MIROC5)

About

Hourly sea level data include contributions from astronomical tides, regional and local weather influences, shorter period climate fluctuations (e.g. El Nino and other climate patterns), as well as long-term (decade to century timescale) change in regional sea level (Pierce et al. 2018).

The regional sea level rise projections leverage a probabilistic framework originally developed by Kopp et al (2014). The probabilistic framework is helpful because despite substantial advances in the science of sea level rise, significant uncertainty remains in mid- and late-century projections of sea levels. Probabilistic sea level rise projections provide a range of possible outcomes in a framework that enables decision-makers to choose a number that is appropriate for their level of risk tolerance (e.g., a wastewater treatment plant vs. a parking lot).

Two sets of probabilistic sea level rise projections for California were generated for both RCP 4.5 and RCP 8.5 greenhouse gas emission scenarios. Both sets of projections incorporate estimates of components that contribute to global and regional sea level rise e.g. thermal expansion of seawater, glacier ice melt, glacial isostatic adjustments, etc. However, the second set of projections also incorporates relatively recent (DeConto and Pollard 2016) scientific findings on the potential for rapid demise of the West Antarctic Ice Sheet, which could dramatically accelerate sea level rise in the latter decades of this century. Sea level rise scenarios presented here include the 50th percentile (middle estimate), 95th percentile (high estimate), and 99.9th percentile (extreme estimate).

References
  • Pierce, D. W., J. F. Kalansky, and D. R. Cayan, (Scripps Institution of Oceanography). 2018. Climate, Drought, and Sea Level Rise Scenarios for the Fourth California Climate Assessment. California’s Fourth Climate Change Assessment, California Energy Commission. Publication Number: CNRA-CEC-2018-006.
  • Kopp, R. E., R. M. Horton, C. M. Little, J. X. Mitrovica, M. Oppenheimer, D. J. Rasmussen, B. H. Strauss, and C. Tebaldi, 2014: Probabilistic 21st and 22nd century sea‐level projections at a global network of tide‐gauge sites. Earth’s Future, 2, p. 383-406
  • DeConto, R.M. and Pollard, D. (2016): Contribution of Antarctica to past and future sea-level rise. Nature 531, 591-597.

Data Sources

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Hourly Sea Level Projections generated for California's Fourth Climate Change Assessment

Scripps Institution Of Oceanography - University of California, San Diego

Hourly sea level projections made at nine locations along the California coast with reliably continuous coastal tide gauge data since before 1984. These data inlcude contributions from astronomical tides, regional and local weather influences, shorter period climate fluctuations (e.g. El Nino and other climate patterns), as well as long-term (decade to century timescale) change in regional sea level under RCP 4.5 and RCP 8.5 and different global climate models. The long-term sea level rise projections is projected probabilistically based on the Kopp et al. (2014) methodology with a modification of using additional sea level rise contributions from loss of Antarctica ice sheets modeled by DeConto & Pollard (2016).