It's not even close.
In a prior posting, the empirical evidence from a group of high quality tidal gauge locations revealed the long-term acceleration and deceleration of sea levels.
Overall, the last 30 years exhibited a trend of only 9-10 inches per century - certainly not a biggie even worthy of a climate-doomsday claim. This trend has been exceeded in the past, prior to the accumulation of high levels of CO2 gases in the atmosphere.
Despite this known evidence, over the last decade and a half much has been made of the claim that CO2 emissions were causing the seas to rise ever faster and would soon result in a literal swamping of Pacific islands.
But what does the actual non-tidal gauge empirical evidence say about the sea rise in the Pacific?
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A. Map of Pacific sea height coordinates
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B. Sea height anomalies & trends
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C. 3-yr moving avgs of sea heights
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D. Fitted trends Pacific island sea heights
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(click on any image to enlarge)
Using the satellite observations, compiled by the leading sea level research group's site, one can download sea surface height anomalies from the beginning of the 21st century. This empirical evidence should clarify if civilization's massive CO2 emissions over the last 15+ years have caused a dangerous sea rise surge of ever higher waves.
And it does clarify.
- Image 'A' above shows 32 ocean locations that were downloaded for this analysis. (There are four corner locations for each island region.)
- Image 'B' contains the plots of each island region's average sea surface anomalies (monthly increase/decrease). While the sea heights can very significantly, the overall trend from the average anomalies (see dark green curve) is an underwhelming +1.8 mm/year - that translates to per century trend of 7.2 inches/century (the bright red trend line).
- Image 'C' is the 3-year (36-mth) simple moving averages from the same anomaly datasets of 'B'. Again, the 3-year trends show variation, but for the most part, within a tight band.
- Image 'D' is a plot of the datasets' fitted trends, which better show the increase/decrease cycle of the anomalies, which is difficult to discern from image 'B'. These trends reveal a similar up/down pattern that was evident in the prior analysis of the longer record from the tidal gauges.
The empirical evidence is rather convincing when it comes to a lack of rapidly rising sea heights around Pacific islands and atolls.
With that said, there indeed may be certain Pacific regions and specific island situations that are experiencing a greater acceleration of rising sea levels. But one would be hard-pressed to claim a unique location (or several) represents the result of CO2-induced global climate change when scientific measurement-reality obviously indicates accelerating, doomsday sea level rise is not a global phenomenon.
Notes: Download Excel spreadsheet with sea height anomaly datasets (and comments) for these 8 island regions: Hawaii, Tuvalu, Midway, Nauru, Wake, Tahiti, Norwalk and Marshall. Plots and trends produced from a January 2000 start date in order to identify the 21st century sea level rise conditions versus the claims.