Guest Essay by Kip Hansen
(h/t Steve Case and Dave Burton)
Prologue: I have been writing recently about Sea Level Rise, both as particular local examples ( Guam, Canton, Miami, New York, and NY/NJ ) and in the series SEA LEVEL: Rise and Fall, of which this is the fourth-plus installment.
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In Part 4, I showed how one gets a rise out of nothing, a neat trick performed by Nerem et al. That’s R. Steven Nerem, of the CU Sea Level Research Group. The blinking image is the summary of that essay.
Doubling down on that neat bit of work, Nerem et al. have a new paper [link replaced — early access version returns error — this link now downloads full .pdf] out that magically (literally) manages to find an acceleration in Global Mean Sea Level Rise that will produce 65 cm ± 12 cm of sea level rise by the year 2100. In inches, that’s 25.6 inches ± about 5 inches.
It is important to note that this new-found acceleration is not based on any change in the sea surface height of Planet Earth.
Others will be writing and posting on the new CU study, I’m sure.
I will respond to it with a simple LINK to my early post, SEA LEVEL: Rise and Fall – Part 4 – Getting a Rise Out of Nothing, and these two annotated graphs from the CU study:
Alternately, we could simply drop the bad TOPEX-A data altogether and look at the more reliable remainder of the data series:
The claimed new-finding of acceleration is based on three cumulative adjustments to the already-known-to-be-faulty TOPEX-A data 1993-1998.
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I am sorry to have to inform you, though, that it is STILL worse than we thought. You see, the data used in determining satellite-based SLR in the above data and graphs, is not really a rise in the sea surface HEIGHT. That is, it does not represent (and never has) an actual increase in the level of the sea surface above the geoid (or, easier to imagine, increasing distance from the center of the Earth). Real sea level rise is reflected in a rise in Global Mean Sea Surface Height. But Global Mean SLR, as calculated by Colorado’s Sea Level Group, NOAA, and other SLR groups is a concept — not a measurement. I once used the phrase “imaginary number” to describe this type of non-physical metric — a number said to represent something in the real world, but in actuality, being something different altogether. I discuss in general how this comes about in an essay “What Are They Really Counting”. SLR satellite data includes things such as the “GIA Adjustment” — which is the amount of SLR that there would have been if the ocean basin hadn’t increased in volume and in the case of this new study, how much higher the sea surface would have been if it had not been suppressed by the Mount Pinatubo volcanic eruption, another correction for ENSO/PDO “computed via a joint cyclostationary empirical orthogonal function (CSEOF) analysis of altimeter GMSL, GRACE land water storage, and Argo-based thermosteric sea level from 2005 to present”, as well as other additions and adjustments — NONE OF WHICH can actually be found manifested in any change to the physical Sea Surface Height. But that’s a torrid tale for another time.
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Take Home Messages:
- Overall, the seas have been rising, slowly and inexorably, since the end of the last Ice Age, with some blips and bumps along the way. In general, they will continue to do so for the foreseeable future — at somewhere between 4-12 inches [10-30cm] per century. This rate is an imminent threat to populated areas built nominally at today’s existing sea level.
- It does not seem that sea levels are rising dangerously or rapidly, nor is the rise accelerating, on a global scale — though our ability to measure global changes at these very small (millimetric) magnitudes is highly questionable.
- All of the above could mean that the constant drumbeat of doom regarding rising sea levels is based on the same sort of Computational Hubris that has brought us “average global temperature anomaly” in place of average global surface temperature.
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Author’s Comment Policy:
I am always happy to read your comments and to try and answer your on-topic questions.
Sea Level Rise is an ongoing Scientific Controversy. This means that great care must be taken in reading and interpreting the past data, new studies and especially media coverage of the topic [including this series!] — bias and advocacy are rampant, opposing forces are firing repeated salvos at one another in the journals and in the press [this essay is about the latest salvo from Steve Nerem] and the consensus may well simply be “an accurate measure of the prevailing bias in the field.” (h/t John Ioannidis)
Sea Level Rise is being blatantly used as a scare tactic by advocates of Catastrophic Anthropogenic Global Warming/Climate Change. Sea level Rise — by now well-known to the general public as less than a foot per century — has been supplanted by Dangerous Sea Level Rise Acceleration as a talking point.
I expect to see a much more detailed examination of this study and this topic from other authors here soon. Judith Curry is posting an ongoing series on sea level rise at her place, Climate Etc.
If you are speaking directly to me in your comment, begin it with “Kip…” so I am sure to see it.
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