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Sea level rise less than 1mm for last 125 years in Kattegatt, Europe — Nils-Axel Morner

Posted By Joanne Nova On June 28, 2014 @ 12:40 pm In Global Warming | Comments Disabled

Nils‐Axel Mörner has a new paper out (his 589th). For 60 years he has been tracking the coastlines close to him, and carefully isolated the exact part which appears to be the most stable. From that he shows that the real sea-level rise in Northern Europe is less than 1 millimeter a year since 1890. This is less that the 1.6mm trend in 182 NOAA tide gauges, and far below the estimates of the IPCC reports.

There is also no sign of acceleration in sea-levels for the last 50 years. (How much should Europeans spend to stop a 1mm annual rise that was already going in 1890 and has not changed much since then?) If anything, Nils work shows how difficult it is to measure true sea-level rise on land that shifts.

In this graph below, he compares the rise of most tide gauges with the Kattegatt region, and the IPCC results. This is only one result from one place, but it is based on thousands of readings from sites all around Kattegatt. His painstaking attention to extreme detail and empirical data stands in stark contrast to the IPCC where the trend depends heavily on adjustments. (Those adjustments appear to be based on a tide gauge in Hong Kong that is subsiding compared to the four other records nearby). Nils notes that people once thought true eustatic sea level changes would be the same all over the world, but this is not so. He remarks that the search for a meaningful mean global rate has become “illusive”.

Nils explained that the superb thing with the Kattegatt region is that we have both a perfect control on the crustal movements, as well as a number of fine tide gauges, so, we can separate the two factors in a way hardly possible anywhere else.

FIG. 1. SPECTRUM OF RATES OF SEA LEVEL CHANGES IN RELATION TO THE DISTRIBUTION OF RATE VALUES OF THE NOAA TIDE GAUGE STATIONS [18, 22, 24]. ESTIMATES OF RISE BY THE IPCC FOR YEAR 2100 (GREEN ARROWS) [1], SATELLITE ALTIMETRY (+3.2 mm/yr) [23], MEAN OF 182 NOAA TIDE GAUGE STATIONS (+1.6 mm/yr) [24], THE NEW DATA FROM THE KATTEGATT SEA HERE PRESENTED (+0.8‐0.9 mm/yr), AND THE VALUE FROM SOME KEY SITES (±0.0 mm/yr) [22, 24].

The rise since 1890 is consistent, slow, and linear.

FIG. 5. TIDE GAUGE RECORDS OF KORSÖR, NYBORG AND AARHUS AS PRESENTED BY NOAA [18]. KORSÖR LIES RIGHT AT THE ZERO ISOBASE OF UPLIFT, AND THE SEA LEVEL RECORD (+0.81 ±0.18 mm/yr) SHOULD HENCE REPRESENT REGIONAL EUSTASY. (His graph includes two other areas, not shown here) THIS IMPLIES THAT ALL THREE RECORDS GIVE A CONGRUENT RECORD OF A REGIONAL EUSTATIC RISE IN THE ORDER OF 0.8‐0.9 mm/yr (THE MEAN BEING +0.87 ±0.15 mm/yr). THIS TREND HAS REMAINED STABLE OVER THE LAST 125 YEARS.

To show how much work goes into analyzing land masses for their tilt and change in height, here is one graph of norther Europe. The boxed area (Kattegatt) lies on the edge in between areas which are moving in opposite directions.

 

FIG. 2. GEOMETRY OF THE TOTAL AMOUNT OF GLACIAL ISOSTATIC UPLIFT OF FENNOSCANDIA [8, 9, 16]. THE KATTEGATT SEA REGION OCCUPIES THE MARGINAL ZONE AND TRANSITION FROM UPLIFT (YELLOW) TO SUBSIDENCE (BLUE). IT IS MARKED WITH AN OPEN BOX CORRESPONDING TO FIG. 4.

 

A close up map of the area. The top graph shown is of Korsor, marked below.

FIG. 4. THE UPLIFT PROFILE OF THE KATTEGATT REGION: AS ESTABLISHED FROM 40 SYNCHRONOUS SHORELINES [2, 3] AND THE ISOBASES OF THE PRESENT RATE OF UPLIFT (in mm/yr) AS ESTABLISHED FROM A COMBINATION OF GEODETIC  BENCHMARKS AND SHORELINE DATA [5]. THE THREE TIDE GAUGES [18] (RED DOTS) LOCATED AT OR CLOSE TO THE ZERO POINT OF UPLIFT (WHICH HAS REMAINED STABLE FOR AT LEAST 8000 YEARS) ARE HERE ANALYSED WITH RESPECT TO  PRESENT REGIONAL EUSTASY. THE EXTRAPOLATION OF THE ISOBASES TO THE EAST WOULD IMPLY A TRANSITION TO AN E–W EXTENSION IN THE BALTIC REGION.

ABSTRACT

Changes in global sea level is an issue of much controversy. In the Kattegatt Sea, the glacial isostatic component factor is well established and the axis of tilting has remained stable for the last 8,000 years. At the point of zero regional crustal movements, there are three tide gauges indicating a present rise in sea level of 0.8 to 0.9 mm/yr for the last 125 years. This value provides a firm record of the regional eustatic rise in sea level in this part of the globe.

CONCLUSIONS

The eustatic changes in sea level were originally held to be the same all over the globe [21]. We now know that this is not correct [3, 22] and that sea level changes significantly over the globe. The search for a mean rate of sea level change has become almost illusive as illustrated in Fig. 1. The pros and cons in this debate lie outside the scope of the present paper.

In this paper, focus is set on one single region: the Kattegatt Sea. The reason for this is that we here have a condensed record of the sea level changes and postglacial isostatic uplift [2‐9]. The direction of uplift and the location of the zero isobase (hinge between uplift to the NE and subsidence to the SW have remained stable over the past 8000 years [4, 5] as evidenced by 12 individual shorelines (Fig. 3) [2‐9], 39 benchmarks along the Swedish West Coast [3, 7] and available tide gauges [3, 16‐18].

At, and close to, the line of zero uplift over the last 8000 years, there are three tide gauge stations [13], which are here used in order to define the regional eustatic component in the Kattegatt region. The three sites give a converging picture: a eustatic component indicating a rise in the order of 0.8‐0.9 mm/yr.

Whatever sea level may be doing in other part of the world, the mean regional eustatic value of the last 125 years is hereby shown to have been about 0.8‐0.9 mm/yr in the Kattegatt region (Fig. 1).

A second outcome of the analysis is that there are no signs of any acceleration in the last 50 years.

REFERENCES

Nils‐Axel Mörner (2014) Deriving the Eustatic Sea Level Component in the Kattaegatt Sea,  Global Perspectives on Geography (GPG). American Society of Science and Engineering, Volume 2, 2014, www.as‐se.org/gpg

Mörner was born in Stockholm, Sweden. He took his Ph.D. in Quaternary Geology in 1969. He became
associate professor in Quaternary Geology in 1969, and in General and Historical Geology in 1981. He
held a personal Associate Professorship at the Swedish Research Council in Paleogeophysics &
Geodynamics from 1978. He was head of the institute on Paleogeophysics & Geodynamics at Stockholm
University (1991‐2005). Major fields: sea level changes, paleoseismology and neotectonics, Sun‐Earth
interaction.

 He has personal field experiences from 49 different countries scattered all over the globe. He has an extensive publication. This is his paper no. 589. 

UPDATE: See Nils comment on this post below .

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