Scripps Oceanography researchers say they've uncovered evidence suggesting that a changing wind pattern could raise sea levels along California's coast. Peter Bromirski is an associate project scientist at Scripps. His study, published in a journal of the American Geophysical Union (subscription required), points out that worldwide, sea level rise boomed upward 50% during the nineties:
Global sea level rose during the 20th Century at a rate of about two millimeters (.08 inches) per year. That rate increased by 50% during the 1990s to a global rate of three millimeters (.12 inches) per year, an uptick frequently linked to global warming. Rising sea level has consequences for coastal development, beach erosion and wetlands inundation. Higher sea levels could cause increased damage to coastal communities and beaches, especially during coincident high tides, storm surges and extreme wave conditions.
In contrast, lately, California's sea level rise has been mostly...well, flat. Once again, a big player in this phenomenon is our old friend, the Pacific Decadal Oscillation. The PDO is a phenomenon that varies climatic circumstances in the Pacific Northwest - we know where we're at because of sea surface temperature, sea level pressure, and wind patterns. Bromirski's team studied the wind patterns that characterize the PDO - that can suppress sea level rise, or strengthen it, depending on the phase we're in. We've been in a "warm" part of the PDO for decades, this team and others say. That looks to be changing.
When the cycle shifts to its negative "cold" phase, coastal ocean waters will become characterized more by a downwelling regime, where the amount of colder, denser water currently brought to the surface will be reduced. Resulting warmer surface water will raise sea level.
Bottom line: this could catch California's sea level rise stats up to where they are for the rest of the world - even push us a little bit ahead. Two years ago, the Pacific Institute did a report: it was paid for by the California Energy Commission, California Department of Transportation, and the Ocean Protection Council. PI figured out where the vulnerable places are for floods and sea level rise. Including hazardous materials sites: dozens in LA and Orange counties. And people: 14-thousand people in LA County, 16-thousand in Ventura, and 110-thousand in Orange county.
(Click below to get to Pacific Institute's Google map page. The turquoise and purple areas are vulnerable to flood risk and sea level rise, respectively.)
California state agencies are looking at adaptation strategies. They're massively complicated. And, they compete for attention with mitigation requirements - benchmarks to meet for cutting GHG emissions now - there's even a reportcard for that. Still, reports on those strategies - with a specific breakout for what to do about coastal and ocean issues, like vulnerability - are due next month.