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A "Coldspot" of Sea Level Rise Along the West Coast of North America

Paper Reviewed
Parker, A. 2017. Coldspot of decelerated sea-level rise on the Pacific coast of North America. Quaestiones Geographicae 35: 3, doi:10.1515/quageo-2016-0024.

Tide gauges measuring sea levels have long been used at locations across the globe to document changes in relative sea level. And given sufficient time, such measurements can provide an accurate computation of sea level trends.

Focusing on the Pacific coast of North America, Parker (2017) set out to calculate the change in sea level trends for this region using data provided by the Permanent Service on Mean Sea Levels (PSMSL, 2015). Using the latest data update available at the time (from 30 April 2015) Parker determined the average rate of rise for the 20 tide gauges with length exceeding 60 years, obtaining a value of -0.729 mm/yr, which calculation he notes is down in magnitude from the -0.624 mm/yr value he calculated using data from the previous update a year earlier. Thus, he notes that "the West coast [of North America] certainly qualifies as a 'coldspot' of negative accelerations, as the relative sea level is mostly falling with increasing trend."

Commenting on this finding and sea level rise in general, Parker says that "the best indication of the presence or absence of significant global warming is the acceleration in the relative sea level signals at the tide gauges, [which is] so far nowhere to be seen." Continuing, he notes that "over the world, there are areas where the relative rates of rise are higher, and other areas where the relative rates of rise are smaller or even negative," adding that "some of these rates are subject to small positive acceleration and some others are subject to small negative accelerations." However, "averaging of the worldwide tide gauges of sufficient quality and length shows a small rate of rise of sea level of +0.24 mm/year acceleration free," which rate of rise flies in the face of alarmist projections of sea level rises of a meter or more by the end of this century.

Reference
PSMSL. 2015. Relative Sea Level Trends (www.psmsl.org/products/trends; accessed: 1 July 2015).

Posted 15 September 2017