“Modern seas unprecedented”: An insult to geology and sea level research

Is the latest sea-level rise unusual? Kurt Lambeck said it was, based on his version of the Holocene seas, calculated with modeled crustal movements (to try to guess the rises and falls of the beaches where the sea levels were changing). Obedient science reporters broadcast his message to the world without asking a single hard question. But when the error bars are 2 meters wide and the dating estimates range over hundreds of years, I thought it beyond silly to think we could estimate 100-year average sea level rises in the time of Moses. Nils-Axel Mörner agrees, and shows data below from 50 years of research which demonstrates that sea levels are always oscillating, and that in Europe, the US, the Indian Ocean past changes are larger than the current ones. Nils has published nearly 600 papers on observations of sea-levels around the world. He calls the Lambeck paper an “insult” to geologists and sea-level researchers. — Jo

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An insult to geology and sea level research



by Nils-Axel Mörner

Paleogeophysics & Geodynamics, Stockholm, Sweden, (morner AT pog.nu)

In the 60s, there was a vigorous debate whether the postglacial sea level rise occurred as a smooth rise (Shepard, 1963) or an oscillatory rise (Fairbridge, 1961). My own low-amplitude oscillations sea level curve (Mörner, 1969) came as some sort of intermediate solution (Fig. 1). It was derived by the isolations of the isostatic and eustatic component in the spectrum of 40 individual shorelines recorded over 300 km in the direction of tilting in the periphery of the Fennoscandian uplift and dated by numerous C14-dates (Mörner, 1969, 1971). Numerous subsequent records from places scattered all over the world indicate that, indeed, the postglacial rise in sea level occurred in a mode of low-amplitude oscillations (e.g. Pirrazoli, 1991). This is even true for the Late Holocene and the last millennium (e.g. Mörner, 1980; van de Plassche, 2000; Hansen et al., 2012).

In a recent paper, Lambeck et al. (2014) claim – with respect to the Holocene to present sea level changes –

“a progressive decrease in the rate of rise from 8.2 ka to ~2.5 ka BP, after which ocean volumes remained nearly constant until the renewed sea-level rise at 100–150 y ago, with no evidence of oscillations exceeding 15– 20 cm in time intervals ≥200 y from 6 to 0.15 ka BP”.

This is a grave insult to painstaking sea level research and observational facts presented by numerous sea level specialists from sites all over the world. Let me just refer to a few records (which I know well):

in the Maldives, there were 7 sea level oscillations in the last 5000 years, as illustrated in Fig. 2 (Mörner, 2007).

in Connecticut, there were 3 sea level oscillations in the last 1500 years (van de Plassche, 2000) as illustrated in Fig. 3a.

in the SW Sweden – Kattegatt Sea region there were 16 oscillations in the last 10,000 years (Mörner, 1971, 1980) with 4 oscillations in the last 3000 year (Fig. 3b).

in the Kattegatt and the Baltic, sea level oscillations are recorded in response to the Medieval Warm Optimum and the subsequent Little Ice Ages (Åse, 1970; Mörner, 1980, 1999; Ambrosiani, 1984; Hansen et al., 2012).

the world is full of other records indicating the presence of Late Holocene sea level oscillations (e.g. Pirazzoli, 1991).

Fig. 2. The Late Holocene sea level changes in the Maldives (Mörner, 2007) including 7 transgression peaks in the last 4000 years with 3 peaks in the last millennium.

Fig. 3. Late Holocene sea level fluctuation:

(a) from Connecticut by van de Plassche (2000) with removal of 1.0 mm/yr subsidence. Note that the AD 1000 peak was larger and faster than today’s rise.

(b) from Stockholm, Sweden, by Mörner (1980, 1999) with removal of 4.9 mm/yr uplift.

Note the rates and peaks of previous eustatic peaks. Both curves show ups and downs (as usual) and nothing unique at present. It is a grave insult to claim that there is an absence of oscillations prior to 1800. What detailed field observations indicate cannot be cancelled by model outputs.

References

Ambrosianli, B., 1984. Settlement expansion – settlement contraction: a question of war, plague, ecology and climate?. In: Climatic Change on a Yearly to Millennial Basis, N.-A. Mörner & W. Karlén, Eds, p. 241-247, Reidel Publ. Co.

Åse, L.-E., 1970. Kvartärgeologiska vittnesbörd om strandförskjutningen vid Stockholmunder de senaste ca. 4000 åren. Geol. Fören. Stockholm Förh., 92, 49-78.

Fairbridge, R.W., 1961. Eustatic changes in sea level, Physics Chemistry of the Earth, 4, 99-185.

Hansen, J.M., Aagaard, T. and Binderup, M., 2012. Absolute sea levels and isostatic changes of the eastern North Sea to central Baltic region during the last 900 years, Boreas, 41, 180–208.

Lambeck, K., Rouby, H., Purcell, A., Sun, Y. and Sambridge, M., 2014. Sea level and global ice volumes from the Last Glacial Maximum to the Holocene. PNAS Early Edition, p. 1-8. www.pnas.org/cgi/doi/10.1073/pnas.1411762111

Mörner, N.-A., 1969. The Late Quaternary history of the Kattegatt Sea and the Swedish West Coast: deglaciation, shorelevel displacement, chronology, isostasy and eustasy. Sveriges Geol. Undersökning, C-640, 1-487.

Mörner, N.-A., 1971. Eustatic changes during the last 20,000 years and a method of separating the isostatic and eustatic factors in an uplifted area. Palaeogeogr. Palaeoclim. Palaeoecol., 9, 153-181.

Mörner, N.-A., 1980. The northwest European “sea-level laboratory” and regional Holocene eustasy, Palaeogeogr. Palaeoclim. Palaeoecol., 1980, 29, 281-300.

Mörner, N.-A., 1999. Sea level and climate: rapid regressions at local warm phases. Quaternary International, 60, 75-82.

Mörner, N.-A., 2007. Sea level changes and tsunamis. environmental stress and migration over the seas. Internationales Asienforum, 38, 353-37.

Pirazzoli, P., 1991. World atlas of Holocene sea-level changes. Elsevier Ocenogr. Ser. 58, 1–300.

van de Plassche, O., 2000. North Atlantic climate-ocean variations and sea level in Long Island Sound, Connecticut, since 500 cal yr A.D, Quaternary Res., 53, 89–97.

Shepard, F.,P., 1963. Thirty-five thousand years of sea level. In: Essays in Marine Geology in Honour of K.O. Emery, T. Clements, Ed, p. 1-10. University of California Press, Berkeley.

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Jo Nova’s post on the Lambeck paper: Sea level rise “unprecedented” when modeling the ancient past

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