California, Oregon, Washington Sea Levels Expected To Rise
June 25, 2012

California, Oregon, Washington Sea Levels Expected To Rise

The sea level of the US West Coast is expected to increase 60 centimeters from Washington to northern California, while waters surrounding the southern half of that state could rise a meter in less than two decades time, claims a National Research Council (NRC) report published Friday.

The study, which was sponsored by Washington, Oregon, and California, was requested in response to the climate change-caused increase in global sea level during the 20th century, the NRC said in a June 22 press release. The goal was to estimate both regional and global sea-level increases for the years 2030, 2050, and 2100.

"The committee that wrote the report projected that global sea level will rise 8 to 23 centimeters by 2030, relative to the 2000 level, 18 to 48 centimeters by 2050, and 50 to 140 centimeters by 2100," the NRC said. "The 2100 estimate is substantially higher than the United Nation's Intergovernmental Panel on Climate Change's projection made in 2007 of 18 to 59 centimeters with a possible additional 17 centimeters if rapid changes in ice flow are included."

"For the California coast south of Cape Mendocino, the committee projected that sea level will rise 4 to 30 centimeters by 2030, 12 to 61 centimeters by 2050, and 42 to 167 centimeters by 2100," the organization added. "For the Washington, Oregon, and California coast north of Cape Mendocino, sea level is projected to change between falling 4 centimeters to rising 23 centimeters by 2030, falling 3 centimeters to rising 48 centimeters by 2050, and rising between 10 to 143 centimeters by 2100."

The projections for southern California are higher than the worldwide projections due to the subsiding of that area's coastline, they said. Conversely, lower sea levels for the northern area of the state, as well as for Oregon and Washington, are due to rising land resulting from plate tectonics -- specifically, the descending of the ocean plate below the continental plate at the Cascadia Subduction Zone.

The experts also discovered that natural disasters or extreme events could cause more rapid sea level rising than the committee predicts, they said. For example, a magnitude 8.0 earthquake in the area north of Cape Mendocino could cause a sudden sea-level increase of at least a meter.

Gary Griggs, Director of the Institute for Marine Sciences at the University of California at Santa Cruz, told USA Today that the most immediate threat in the decades ahead will come from El Nino. During those events, the ocean warms, elevating sea level and creating larger than normal waves during high tide, especially in the northwest, Griggs said.

"The report was commissioned by states and federal agencies looking for detailed information so they can plan for an accelerated rate of erosion along beaches, bluffs and sand dunes that are already crumbling into the sea," the newspaper said. They also added that the research "summarized published projections, such as the IPCC report of 2007, and updated it with computer modeling, as well as an analysis of tidal gauge readings and satellite measurements along specific sites on the West Coast."