Sea Level Rise

The Pacific Northwest coast includes a wide diversity of coastal habitats from including bluffs, sandy beaches, coastal marshes, tidal flats and eelgrass beds, supporting myriad species of fish and wildlife as well as local economies and cultural history. These coastal habitat are threatened by various human activities due to continued population growth and pressures for development, which will be exacerbated by climate change.

Dr. Patti Glick from the National Wildlife Federation and Dr. Jonathan Clough used the model SLAMM to study the potential impact of sea-level rise on key coastal habitats in the Pacific Northwest, hoping to assist coastal managers and other relevant decision-makers identify and implement strategies to minimize the risks.

Model results vary considerably by site, but their report finds that, overall, the region is likely to face a dramatic shift in the extent and diversity of its coastal marshes, swamps, beaches, and other habitats due to sea-level rise. For example, if global average sea level increases by 0.69 meters (27.3 inches), the following impacts are predicted by 2100 for the sites investigated:

• Estuarine beaches will undergo inundation and erosion to the tune of a 65 percent loss.
• As much as 44 percent of tidal flat will disappear.
• 13 percent of inland fresh marsh and 25 percent of tidal fresh marsh will be lost.
• 11 percent of inland swamp will be inundated with salt water, while 61 percent of tidal swamp will be lost.
• 52 percent of brackish marsh will convert to tidal flats, transitional marsh and saltmarsh.
• 2 percent of undeveloped land will be inundated or eroded to other categories across all study areas.

Climate change is also changing the face of the Chesapeake Bay by accelerating the rate of sea-level rise. At risk is an amazing diversity of coastal habitats including barrier islands along the Atlantic Coast. A short report by Dr. Glick and Amenda Staut and Brad Nunley summarizes the results of a detailed modeling analysis, also using Jonathan Clough's SLAMM model, commissioned by the National Wildlife Federation of how Chesapeake Bay habitats will be affected by sea-level rise in the coming century.

Dr. Glick and colleagues maps of future sea level rise extent along both coast of the US are available in Data Basin in two galleries: Chesapeake Bay region sea-level rise modelling and Pacific Northwest sea-level rise modelling.