California Sea-Level Rise Reality Check

Russ Steele

I was doing some research on an article that appeared in The Union this weekend titled: Scientist: Recent storms consistent with warming planet. I was investigating the snow pack claims in the article, when I stumbled across some sea-level rise claims by the California Department of Water Resources in a document referenced in The Union article. It was a Department of Water Resources report on Managing an Uncertain Future: Climate Change Adaption Strategies for California's Water.  The report has this to say about Sea-Level Rise

Sea levels are rising, and it is generally accepted that this trend will continue. However, the exact rate of rise is unknown, due to ongoing scientific uncertainty about the melting of ice sheets on western Antarctica and Greenland and the potential for abrupt changes in ocean conditions. Recent peer-reviewed studies estimate a rise of between seven to 55 inches by 2100 along California’s coast.

Here is a little reality check on sea level rise in a study by  J.R. Houston and R.G. Dean, and published in the Journal of Coastal Research, titled: Sea-Level Acceleration Based on U.S. Tide Gages and Extensions of Previous Global-Gage Analyses.

Here is the Abstract from the paper.

Without sea-level acceleration, the 20th-century sea-level trend of 1.7 mm/y would produce a rise of only approximately 0.15 m from 2010 to 2100; therefore, sea-level acceleration is a critical component of projected sea-level rise. To determine this acceleration, we analyze monthly-averaged records for 57 U.S. tide gauges in the Permanent Service for Mean Sea Level (PSMSL) data base that have lengths of 60–156 years. Least-squares quadratic analysis of each of the 57 records are performed to quantify accelerations, and 25 gauge records having data spanning from 1930 to 2010 are analyzed. In both cases we obtain small average sea-level decelerations. To compare these results with worldwide data, we extend the analysis of Douglas (1992) by an additional 25 years and analyze revised data of Church and White (2006) from 1930 to 2007 and also obtain small sea-level decelerations similar to those we obtain from U.S. gauge records.

Read that carefully, over a 80 year period sea-levels are decelerating, not accelerating as postulated in the Water Resources Report. Based on this report California coastal and bay area communities are being forced to develop plans for a 55 inch rise in sea levels. This planning and associated mitigation is costing cities money they do not have. 

Full report is here. Stay tuned for the snow pack post.