December 22, 2014

Vertical land movement, caused by sediment settling, groundwater extraction, and tectonic forces, can boost or reduce the local effects of global sea level rise.  Conventional wisdom says that the offshore collision of two continental plates is pushing up Washington’s and Oregon’s coastlines. This assumption may make coastal communities complacent about climate change and sea level rise. Using tidal-gauge and GPS readings, Washington Sea Grant’s Ian Miller and colleagues have found that vertical land movement actually varies dramatically along Washington’s shores. While the Olympic Coast’s northwest corner is rising, the land is actually subsiding as little as 30 miles down the coast – and along densely populated Puget Sound. Communities need local data to prepare for rising seas.