Projected sea level rise for Washington State

A report from the Washington Coastal Resilience Project provides an updated assessment of projected sea level change for coastal Washington State and its relationship to coastal hazards such as flooding and erosion. 

Report cover
Report cover

Report introduction (excerpt)

This report provides a summary of new projections of sea level rise for Washington State. These projections improve on previous estimates (NRC, 2012 ;, Mote et al., 2008) by:

  • Incorporating new science about the processes contributing to global sea level rise, including new understanding of the dynamics of melt for the Greenland and Antarctic ice sheets,
  • Accounting for community-scale differences in vertical land movement along Washington’s coastlines, and
  • Estimating the probabilities that various amounts of sea level rise will occur for a given greenhouse gas scenario.

These projections can be used to inform coastal risk assessments, planning, decision making and ongoing management for Washington’s coastal communities. Future greenhouse gas emissions depend on human behavior: technological
innovation, geopolitics, population growth, etc. As a result, there is no reliable way to estimate the probability of following a particular emissions trajectory. Instead, we have developed a separate set of probabilistic projections for both a low and a high greenhouse gas scenario.

We present our projections in terms of the probability of exceedance, or the likelihood that sea level rise will meet or exceed a particular elevation relative to contemporary sea level. Recent research has emphasized the potential for large amounts of sea level rise, and today’s high-end projections are much higher than those of previous studies. In order to minimize the chance that our high-end projections are similarly revised upward in the future, we have also included a very high magnitude projection, which multiple studies indicate is a likely upper bound for future sea level rise by 2100.


Miller, I.M., Morgan, H., Mauger, G., Newton, T., Weldon, R., Schmidt, D., Welch, M., Grossman, E. 2018. Projected Sea Level Rise for Washington State – A 2018 Assessment. A collaboration of Washington Sea Grant, University of Washington Climate Impacts Group, Oregon State University, University of Washington, and US Geological Survey. Prepared for the Washington Coastal Resilience Project.

Download the full report (external link)