Sea Levels along CA, Northeast Coasts Rising Faster than Average

Three new studies assess predicted sea level rise both locally—U.S. west and east coasts—and globally. Authors of the global study, published in Nature Climate Change, found that even if global temperature rise peaks at a 3.6-degree F increase over preindustrial times—a limit that many scientists believe is unachievable given the current rate of carbon dioxide emissions—global sea level will continue to rise for almost three centuries, reaching a level almost 9 feet above 2000 levels by 2300. However, the authors also found that if temperatures can be kept at a 2.7 degree F increase over preindustrial times, then sea level rise could be reduced to an estimated 5 feet by 2300.

Acknowledging that sea level rises at different rates in different regions, two other new studies assessed predicted changes on a local level. Authors of one study, also published in Nature Climate Change, found that on the North American Atlantic Coast between North Carolina and Massachusetts, sea level has risen at a rate about 3-4 times higher than the global average—1.97±0.64mm local rise compared with 0.59±0.26mm global rise—since 1950, having large implications for future sea level rise and its impacts on coastal cities.

Rates of sea level increase are also higher than the global average along the coast of California, according to a third study, published by the National Academy of Sciences. The study, conducted by state and federal organizations from California, Oregon, and Washington, assessed sea level rise along the U.S. west coast and finds that south of Cape Mendocino in northern California, sea level will rise by an estimated 1.4 to 5.5 feet by 2100, relative to 2000 levels. North of Cape Mendocino—including the coasts of Washington, Oregon, and northern California—sea level is projected to rise 0.3 to 4.7 feet by 2100.