 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
| . |  |
. |
Washington DC (SPX) May 05, 2011 The West Coast of North America has caught a break that has left sea level in the eastern North Pacific Ocean steady during the last few decades, but there is evidence that a change in wind patterns may be occurring that could cause coastal sea-level rise to accelerate beginning this decade. That is the conclusion of a new study that says that conditions dominated by cold surface waters along the West Coast could soon flip to an opposite state. "There are indications that this is what might be happening right now," says Peter Bromirski, a researcher at Scripps Institution of Oceanography, UC San Diego, and lead author of a study now in press in the Journal of Geophysical Research-Oceans, a journal of the American Geophysical Union. Global sea level rose during the 20th Century at a rate of about two millimeters (0.08 inches) per year. That rate increased by 50 percent during the 1990s to a global rate of three millimeters (0.12 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. Scientists date the current phase of a Pacific Ocean climate cycle called the Pacific Decadal Oscillation (PDO) to the mid- to late-1970s. The current "warm" phase is characterized by the upward movement, or upwelling, of cold water toward the surface along the West Coast. Despite a few El Nino-induced surges in sea level during that time, the coastal sea level trend has mostly been steady. 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. Bromirski and fellow Scripps oceanographers Art Miller, Reinhard Flick and Guillermo Auad studied the wind stress patterns that characterize the different phases of the PDO. Wind stresses can act to change the characteristics of the coastal upwelling/downwelling regime ( i.e. suppress or raise sea level). The authors write that the characteristics of wind stress variability over the eastern North Pacific "recently reached levels not observed since before the mid-1970s regime shift. This change in wind stress patterns may be foreshadowing a PDO regime shift, causing an associated persistent change ...that will result in a concomitant resumption of sea level rise along the U.S. West Coast to global or even higher rates." Several state and federal agencies, led by the California Department of Boating and Waterways, funded the study. Support also came from NOAA, the National Science Foundation, and the California Energy Commission.
Share This Article With Planet Earth
Related Links American Geophysical Union Climate Science News - Modeling, Mitigation Adaptation
Climate Change Analysis Predicts Increased Fatalities from Heat WavesBaltimore MD (SPX) May 04, 2011 Global climate change is anticipated to bring more extreme weather phenomena such as heat waves that could impact human health in the coming decades. An analysis led by researchers at the Johns Hopkins Bloomberg School of Public Health calculated that the city of Chicago could experience between 166 and 2,217 excess deaths per year attributable to heat waves using three different climate c ... read more |
|
|
| The content herein, unless otherwise known to be public domain, are Copyright 1995-2010 - SpaceDaily. AFP and UPI Wire Stories are copyright Agence France-Presse and United Press International. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by SpaceDaily on any Web page published or hosted by SpaceDaily. Privacy Statement |
del.icio.us
Digg
Reddit
YahooMyWeb
Google
Facebook
