John Wiesner again cast cherry-picking allegations in a purportedly scientific letter remarkably devoid of science. He accuses me of avoiding “an obvious upward sea level trend line”, when my previous letter, and many before it, noted that San Francisco sea level has risen 4.2” since 1854. My point has been, and remains, that in the past three decades (since 1983) of unremitting increase of atmospheric CO2, sea levels for six West Coast cities have fallen, not risen.
In previous letters, I've illustrated ad nauseam that sea level rose over 400 feet in the past 12,000 years following the Ice Age, that sea levels were higher than now during the four previous warming periods of the past 10,000 years – sea levels during the Holocene Climate Optimum (8,000-4,000 years ago) were up to ten feet higher – and that current sea level rise is a natural rebound from the drop in sea level that occurred in the Little Ice Age (1450-1850AD). (Click here for more information about previous higher sea levels.)
Mr. Wiesner wrote that I refuse to discuss fitting an RMS trend line to the data. Although I can’t find any refusal, I wonder why Mr. Wiesner didn’t do it? I’m pleased to add it now. For San Francisco, the mean sea level trend is 2.01 millimeters/year with a 95% confidence interval of +/- 0.21 mm/yr; San Diego, 2.06+/-0.20mm/yr; Los Angeles, 0.83+/-0.27mm/yr; Seattle, 2.06+/-0.17mm/yr; Vancouver, 0.37+/-0.23mm/yr; Victoria, 0.63+/-21mm/yr. Maximum increase per century: a modest 8”.
These are the links to the RMS trend lines:
Using another statistical tool, variation of 50-year mean sea level trends, five cities show a decreasing rate, and one (Victoria) shows no change, for the past half-century. My point, given recent and historical trends, sea level increase this century should be about 8”(or less), just like the past two centuries.
These are the links to the variations of 50-year mean sea level trends: