Guest Post by Willis Eschenbach
My Twitter friend Wei Zhang @WeiZhangAtmos pointed me to an open-access study in Nature magazine entitled “Timing of emergence of modern rates of sea-level rise by 1863“. It claims that sea levels were basically stable for centuries, all the way up until the 1860s when the modern rates of rise started occurring. They are basing this claim on a variety of different kinds of proxy sea level data—foraminifera, coral microatolls, plants, diatoms, peat, shells, vermetids, herbaceous peat, mangrove peat, ∆13C, sediment, testates, archeological, and bioconstructed reefs.
Intrigued, I took a look. Here’s their Supplementary Figure 5.
Figure 1. Figure 5 from the Supplement, with original caption
Hmmm … overall, that wasn’t impressive in the slightest. Different areas are claimed to have wildly differing rates of change, sometimes going up and down radically in a couple of hundred years. Why would New Jersey be so different from North Carolina? Why do Iceland and Denmark show no change in sea level until very recently, when relative sea level is supposed to have dropped? These questions and more …
I noted an interesting point in the caption to Supplementary Figure 5 above. It said that the “global and linear” components had been removed. Hmmm again … how was that done?
Reading the paper I found the magic behind the curtain. The finished records in Fig. 5 above are the result of the raw data being “incorporated into a spatiotemporal empirical hierarchical model” … and hey, if you don’t believe in the millimeter-level accuracy of a random spatiotemporal empirical hierarchical model, you must be anti-science.
Now, those who know me are aware that I’m a great fan of raw data. And kudos to the authors, they included a link to download an Excel spreadsheet containing the data. It contains proxy data from 103 different sites around the world. So I took that proxy data and I graphed it all up.
Figure 2. The proxy data used in the sea level study.
YIKES! All I can say is, it’s a darn good thing that they have their spatiotemporal empirical hierarchical macerator … because if they’d shown the unmacerated data, they’d have to provide 500ml of eyebleach with every issue of the magazine …
With that data as a starting point, as you might expect, their claims are all over the map. Regarding the North Atlantic, for example, they say that the emergence of modern rates of sea-level rise occurred “earliest in the mid-Atlantic [US] region (1872–1894 CE) and later in Canada and Europe (1930–1964 CE)”.
Seriously? After centuries during which their claim is that there was very little sea-level rise (Fig 1.), they say that one side of the Atlantic started rising about a half-century before the other side of the Atlantic, leaving the entire Atlantic tilted … wait, what?
And climate scientists wonder why the general public is so skeptical of their findings?
My very best wishes to all, stay safe and sane in these parlous times …
My Custom: I ask you to quote the exact words you’re discussing. Misunderstandings are a bane of the intarwebs, and vague claims based on what someone thinks someone else meant are a major source of said confoundibulations.