Sea Level Rise Projections

Sea Level Rise Projections There are high levels of uncertainty associated with projections of future climate, and in turn the projection of future sea level. Uncertainties in climate models include greenhouse gas emissions scenarios and contribution of ice melt to sea level. We therefore analyzed hazards for three levels of sea-level rise (SLR), including projection of historical trends, low acceleration, and moderate acceleration. Projection of historical levels at each time was calculated using the observed historical rate of sea level rise at the Annapolis tide gage (3.4 mm/yr) and extrapolated from present day (2012) to the given years. The low and moderate SLR acceleration scenarios were estimated using Curves 1 and 2 from the U.S. Army Corps of Engineers sea level rise guidance for civil works projects (EC 1165-2-212, October 2011). This approach provides for a moderate SLR acceleration curve that is consistent with guidance from the Maryland Department of Natural Resources (MD DNR), and a low SLR acceleration curve that provides for a middle ground between those presented by MD DNR and extrapolation of the historical trend. All projections account for both the projected increase in sea level and land subsidence. The three scenarios are presented in the below plot of relative sea-level rise -- represented in feet -- from 2012 onward.