Sea level change in the Middle Ages and the Little Ice Age

De stand van de zeespiegel in de Middeleeuwen en de Kleine IJstijd

F.J.P.M. Kwaad,

physical geographer


In this website, references are given to papers on sea level change in the Middle Ages (500-1500 AD) and the Little Ice Age (LIA; approximately 1450-1850 AD) that can be viewed online.

First, some preliminary remarks are given:
- What is Mean Sea Level (MSL)? It is the (local or global) mean height of sea level. How is MSL defined: as the halfway point between mean high and mean low tide or, expressed otherwise, the mean of mean high tide and mean low tide? According to Fraczek: "MSL is usually described as a tidal datum that is the arithmetic mean of hourly water elevations observed over a specific 19-year cycle. This definition averages out tidal highs and lows caused by the changing effects of the gravitational forces from the moon and sun". See also PSMSL.

- How can Mean Sea Level be determined? Mean Sea Level cannot be measured directly. It must be derived from other measurements (such as hourly tide gauge measurements) or proxy data (sea level marks). For the use of GPS (Global Positioning System) for sea level measurement go to PSMSL.

- How is MSL expressed? The height of Mean Sea Level is given relative to a certain, arbitrary chosen, reference or datum level, e.g. NAP (Dutch Ordnance Datum). Though the zero point of the reference scale (such as NAP) may be so chosen as to coincide with Mean Sea Level, Mean Sea Level is not identical with the zero point. Mean Sea Level may rise or fall, relative to the zero point of the reference scale. This has occurred in The Netherlands since Dutch Ordnance Datum (NAP) was established in 1683. The zero point itself is meant to be stable over time. However: tide gauges may move vertically as a result of movements of the earth's crust, such as post-glacial rebound, tectonic uplift or crustal subsidence. This greatly complicates the problem of determining global sea level change from tide gauge data (From: Tide gauge sea level).

- Mean Sea Level can also be seen as an expression of the Geoid. The Geoid is the shape that the surface of the oceans would take under the influence of Earth's gravitation and rotation alone, in the absence of other influences such as winds and tides. Specifically, the geoid is the equipotential surface that would coincide with the mean ocean surface of the Earth if the oceans and atmosphere were in equilibrium, at rest relative to the rotating Earth, and extended through the continents (such as with very narrow canals) (From: geoid). For more details see: Mean Sea Level, GPS and the Geoid.

- Sea level change at a certain location or in a certain area may be due to eustatic (worldwide) sea level movement and/or to local or regional movement (incl. glacial isostatic adjustment, GIA) of the land. An important aspect of sea level research, therefore, is to try and separate local (or regional) and global influences on sea level. Eustatic change is when the sea level changes due to an alteration in the volume of water in the oceans or, alternatively, a change in the shape of an ocean basin and hence a change in the amount of water the sea can hold. Eustatic change is always a global effect (From: Geography).  

- Local or regional Mean Sea Level may differ from place to place or from one area to the next area, e.g. along the Dutch coast it varies from 0 to 10 cm +NAP. Therefore, local or regional sea level graphs cannot simply be extrapolated to serve as a global mean sea level graph over time.

- Since the ending of the last Ice Age sea level has risen by about 120 m. During the Holocene (the past 10.000 years) the last 35 m of rise have occurred. At first, the rate of rise was very high (>80 cm/100 years). Later (about 7000 years ago) it slowed down considerably, viz. to an average rate of  5 cm/100 years over the last 3000 years around the Atlantic. Since 1810 the rate has increased again, viz. to 19 cm/100 years along the Dutch coast for the period 1891-2012. Some authors claim that a minor fluctuation of sea level of about 30 cm has occurred during the temperature optimum of the Middle Ages and the ensuing Little Ice Age. The present website is about this fluctuation.

- In view of the small magnitude (about 30 cm) of the Medieval sea level fluctuation, the reliability and accuracy of the methods and data used are crucial. As Rahmstorf  (2011) puts it:  To trace the subtle variations of sea level of the last two millennia, more precise methods are required than for the huge and rapid rise of sea level during the first half of the Holocene. This problem has given rise to a rather large number of studies of Medieval sea level change (see the Publications list at the end of the site). No agreement or consensus has been reached so far on the matter.

- The oldest tide gauge readings of sea level date back to 1700 AD e.g at Amsterdam (Van Veen, 1954).

- From the time before 1700 AD, no sea level records, based on tide gauge readings, are known, worldwide.

- Preferably, dated palaeo sea level markers (marine sediments of known age and altitude, containing marine facies fossils; peat layers) are used for the reconstruction of sea level heights before 1700 AD. In this way, Mean High Tide level can be found. Tidal range can vary strongly over short distances along a coast, and also over time due to coast line changes or changes of prevailing wind directions, and Mean High Tide can change more strongly than Mean Low Tide when the shape of the coast changes. Therefore, Mean Sea Level cannot simply be found by subtracting a fixed amount from MHT.

- Dateable palaeo sea level markers are not always available. In fact, they are rare. Therefore, attempts have been undertaken to derive sea level change from temperature change, reasoning that a rise of temperature leads to an expansion and rise of the level of the oceans, worldwide.

Holocene sea level

Holocene sea level rise (From: Robert A. Rhode)

Recent sea level rise

Recent sea level rise (From: Robert A. Rhode)


Changing temperature 0-2000 AD (for explanation see: Robert A. Rhode)

CO2 Law Dome Ice Cores

CO2 level in the Law Dome Ice Cores, East Antarctica, 1000-2000 AD (Source)

Van Veen 1954 fig. 1

For the period 1682-1930 we have the sea level graph, constructed by Van Veen (1954) based on tide gauge readings in Amsterdam. See also: History of Dutch Ordnance Datum (NAP).

Some examples are shown of the sea level rise graphs for the Middle Ages and the Little Ice Age, taken from the publications in the list of references below:

Hofstede, 1991 (German North Sea coast, German Bight):


 Jensen et al., 1993 (based on Hofstede, 1991):

Jensen 1993 Fig.1


Louters en Gerritsen, RIKZ, 1994 Fig. 2.3 (taken from Jensen, 1993):

RIKZ 1994

Figuur 2.3. De gemiddelde hoogwater kromme voor de zuidelijke Noordzee (naar Jensen e.a.,1993) en de gemiddelde wereldtemperatuur (volgens Barth & Titus,1984 ) over de laatste 1000 jaar illustreert dat stijging en daling van de mondiale temperatuur samengaat met stijging en daling van het gemiddeld hoogwater (HW).


Behre, 2003 , Behre, 2007 (German North Sea coast, German Bight):



Behre, 2004, Abb. 2 (German North Sea coast):

Behre 2004 Abb. 2


Klaus Eckart Puls, 2008 (part of Behre's sea level graph, see previous two images):

Behre 2003 Kurve Teil

Abb. 3: Meeresspiegel an der südlichen Nordseeküste
(aus K.-E. BEHRE, Probleme der Küstenforschung, Bd.28, Isensee-Verlag, Oldenburg, 2003)


See also the critical comments on Behre's sea level curve for the southern North Sea (2003, 2004, 2007) by Baeteman, Waller and Kiden (2011) and Bungenstock and Weerts (2010, 2012), and Behre's response (2012).

Baeteman, Waller and Kiden (2011) conclude that the high-amplitude middle and late Holocene sea-level fluctuations identified by Behre (2003, 2007) are highly unlikely to be real features of the sea-level history of the southern North Sea.


North Sea coast of the Netherlands and Belgium

Zeespieegel Nederland TNO

Relative sea level rise during the Holocene along the North Sea coast (TNO-NITG, 2003).

An old question (1950's) is, whether the succession of marine clay and peat layers in the Western part of the Netherlands and Belgium is an indication of fluctuations of sea level during the second half of the Holocene (Atlanticum-Subboreal-Subatlanticum). These clay and peat layers were considered in the past as reflecting phases of transgression and regression of the sea. In 1954 a special issue of the Dutch journal "Geologie en Mijnbouw" appeared about "Quaternary changes in level especially in the Netherlands". Below are two figures, viz. by Van Straaten en Bennema, taken from this issue. They show that already in 1954 the first 'smoothers' and 'wigglers' regarding sea level rise were present.

Van Straaten 1954  Bennema 1954

Sea level rise in the Netherlands according to Van Straaten (1954; left) and Bennema (1954; right). Right click on the figures for larger images.

Recently, as more C14-datings of the marine clay and peat layers became available at more locations in the Netherlands and Belgium, it has become clear, that no specific periods or phases of trans- and regression of the sea can be recognized that have occurred synchronously along the entire Dutch and Belgian coast (the so-called Calais and Duinkerke Deposits). And that therefore these marine clay and peat layers can no longer be considered as evidence of fluctuations of sea level along the Dutch and Belgian coast during the Atlanticum-Subboreal-Subatlanticum. In fact, in the Netherlands no evidence at all for fluctuations of sea level rise during the Atlanticum-Subboreal-Subatlanticum has been found so far. See:
Weerts, H.; Cleveringa, P.; Westerhoff, W.; Vos, P. (2006): Nooit meer: afzettingen van Duinkerke en Calais, Archeobrief (Methoden en Technieken), 28-34. Stichting voor de Nederlandse Archeologie (SNA).

De Boer, G., 2006. Het fysisch-geografisch onderzoek en de ontstaansgeschiedenis van westelijk Zeeuws-Vlaanderen: een status quaestionis. Tijdschrift voor Waterstaatsgeschiedenis 14 (2005); webversie 2006, pp. 48-58.

De Groot, Westerhoff, and Bosch, 1996 wrote about this in 1996 (pp. 69-70):
"In the Netherlands, the rate of relative sea-level rise during the last 2000 years is poorly known, mainly because of the lack of well-datable material associated with sea-level markers concerning that periode."
"Over the last 2000 years there has been non coastal progradation in the western part of the Netherlands and no palaeo sea-level markers were formed."

Here is their Figure 6 of the palaeo Mean High Water (MHW) trend over the last 2000 years on the Frisian Islands:



Grinsted et al., 2009
(Global Sea Level):

Grinsted 2009


Masters, 2009 (Based on Grinsted et al. 2009):

Figure 1. Global sea level from 200 A.D. to 2000, as reconstructed from proxy records of sea level by Moberg et al. 2005. The thick black line is reconstructed sea level using tide gauges (Jevrejeva, 2006). The lightest gray shading shows the 5 - 95% uncertainty in the estimates, and the medium gray shading denotes the one standard deviation error estimate. The highest global sea level of the past 110,000 years likely occurred during the Medieval Warm Period of 1100 - 1200 A.D., when warm conditions similar to today's climate caused the sea level to rise 5 - 8" (12 - 21 cm) higher than present.

Image credit: Grinsted, A., J.C. Moore, and S. Jevrejeva, 2009, "Reconstructing sea level from paleo and projected temperatures 200 to 2100 AD", Climate Dynamics, DOI 10.1007/s00382-008-0507-2, 06 January 2009.


Gonzalez et al., 2009 (Mississippi Delta):

Gonzalez et al. 2009


Kemp et al., 2010 (US Atlantic coast):

Kemp 2010

Rahmstorf, S., 2011. 2000 years of sea level (North Carolina, US Atlantic coast):

"Good data on past sea levels is hard to come by. Reconstructing the huge rise at the end of the last glacial (120 meters) is not too bad, because a few meters uncertainty in sea level or a few centuries in dating don’t matter all that much. But to trace the subtle variations of the last millennia requires more precise methods. Andrew Kemp, Ben Horton and Jeff Donnelly have developed such a method. They use sediments in salt marshes along the coast, which get regularly flooded by tides. When sea level rises the salt marsh grows upwards, because it traps sediments. The sediment layers accumulating in this way can be examined and dated. Their altitude as it depends on age already provides a rough sea level history. But then comes the laborious detail. Although on average the sediment buildup follows sea level, it sometimes lags behind when sea level rises rapidly, or catches up when sea level rises more slowly. Therefore we want to know how high, relative to mean sea level, the salt marsh was located at any given time. To determine this, we can exploit the fact that each level within the tidal range is characterized by a particular set of organisms that live there. This can be analyzed e.g. from the tiny shells of foraminifera (or forams for short) found in the sediment. For this purpose, the species and numbers of forams need to be determined under the microscope for each centimeter of sediment. To get a continuous record of good resolution, we need a site with a rapid, continuous sea level rise. Kemp and colleagues used salt marshes in North Carolina, where the land has steadily sunk by about two meters in the past two millennia due to glacial isostatic adjustment. Thus a roughly 2.5 meters long sediment core is obtained. The effect of land subsidence later needs to be subtracted out in order to obtain the sea level rise proper."

Figure caption. Sea level evolution in North Carolina from proxy data (blue curve with uncertainty range). Local land subsidence is already removed. The green curve shows a reconstruction based on tide gauges from around the world (Jevrejeva et al. 2006, 2008). The red curve shows results from a simple model connecting global temperature with sea level. For the last millennium the sea level curve follows what can be expected from temperature – the two independent reconstructions thus mutually reinforce each other by their consistency. Before 1000 AD there is a discrepancy: warm temperatures in the reconstruction used would lead to rising sea level, but the sea level reconstruction is flat. However, temperature data from before 1000 AD are sparse and less reliable, and lowering temperatures in this period by only 0.2ºC removes the discrepancy. Thus, a possible explanation for the discrepancy is that the temperature reconstruction is a little too warm before 1000 AD.


Publications on sea level change in the Middle Ages and the Little Ice Age

The following papers can be viewed online:

Akasofu, Syun-Ichi, 2010. On the recovery from the Little Ice Age. Natural Science, Vol.2, No.11, 1211-1224 (2010) doi:10.4236/ns.2010.211149
Openly accessible at

Albrecht, Frauke, 2013. Regional Mean Sea Level Changes in the German Bight, Dissertation, Universität Hamburg, 2013, 142 pp.

Augustyn, B., 1992. Zeespiegelrijzing, transgressiefasen en stormvloeden in maritiem Vlaanderen tot het einde van de XVl de eeuw. Een landschappelijke, ecologische en klimatologische studie in historisch perspektief (Dissertatie Gent1991(herzieneversie); Brussel: Algemeen Rijksarchief, 1992, 731blz.).

Baeteman, C., 2008. Radiocarbon-dated sediment sequences from the Belgian coastal plain: testing the hypothesis of fluctuating or smooth late-Holocene relative sea-level rise. The Holocene, December 2008, vol. 18, no. 8, 1219-1228.

Baeteman, C., Waller, M. & Kiden, P. 2011: Reconstructing middle to late Holocene sea-level change: A methodological review with particular reference to ‘A new Holocene sea-level curve for the southern North Sea’ presented by K.-E. Behre. Boreas, 10.1111/j.1502-3885.2011.00207.x. ISSN 0300-9483

Behre, K.E., 2003. Eine neue Meeresspiegelkurve für die südiche Nordsee. Probleme der Küstenforschung im südlichen Nordseegebiet, 28, 9-63, Oldenburg.

Behre, K.E., 2004. Die Schwankungen des mittleren Tidehochwassers an der deutschen Nordseeküste in den letzten 3000 Jahren nach archäologischen Daten. G. Schernewski und T. Dolch (Hrsg.):Geographie der Meere und Küsten Coastline Reports 1 (2004), ISSN 0928-2734 S. 1 - 7 

Behre, K.E., 2007. A new Holocene sea-level curve for the southern North Sea. Boreas, Vol. 36, pp. 82-102.

Behre, K.E., 2012. Sea-level changes in the southern North Sea region: a response to Bungenstock and Weerts (2010). International Journal of Earth Sciences
Behre, K.E., 2013. Die Meeresspiegelschwankungen der vergangenen Jahrtausende und deren Bedeutung für das Siedlungsgeschehen an der deutschen Nordseeküste. The sea-level fluctuations over past millennia and their impact on the settlement process along the German North Sea coast. Siedlungs- und Küstenforschung im südlichen Nordseegebiet (SKN), Settlement and Coastal Research in the Southern North Sea Region (SCN) 36, pp. 13-30.

Bennema, J, 1954. Holocene movements of land and sea-level in the coastal area of The Netherlands. Geologie en Mijnbouw, Nwe Serie, 16, 6, pp. 254-264.

Bungenstock, F., Mauz, B., Schäfer, A., 2004. The late Holocene sea level rise at the East Frisian coast (North Sea): New time constraints provided by optical ages of coastal deposits. In: Schernewski, G., Dolch, T. (eds.). Geographie der Meere und Küsten. Coastline Reports (1), pp. 37-41. 2004.

Bungenstock, F. and Weerts, H.J.T., 2010. The high-resolution Holocene sea-level curve for Northwest Germany: global signals, local effects or data-artefacts? Int J Earth Sci (Geol Rundsch) (2010) 99:1687–1706, DOI 10.1007/s00531-009-0493-6.

Bungenstock, F. and Weerts, H.J.T., 2012. Holocene relative sea-level curves for the German North sea coast. Int J Earth Sci (Geol Rundsch) (2012) 101: pp.1083–1090, DOI 10.1007/s00531-011-0698-3.

Curry, Judith, 2011. Historic variations in Sea Levels. Part 1- from the Holocene to Romans


De Boer, G., 2006. Het fysisch-geografisch onderzoek en de ontstaansgeschiedenis van westelijk Zeeuws-Vlaanderen: een status quaestionis. Tijdschrift voor Waterstaatsgeschiedenis 14(2005); webversie 2006, pp. 48-58.

Dellwig, O., F. Watermann , H.-J. Brumsack and G. Gerdes, 1999. High-resolution Reconstruction of a Holocene Coastal Sequence (NW Germany) Using Inorganic Geochemical Data and Diatom Inventories. Estuarine, Coastal and Shelf  Science(1999)48,617–633.

De Groot, Th.A.M., Westerhoff, W.E. and Bosch, J.H.A., 1996. Sea-level rise during the last 2000 years as recorded on the Frisian Islands (the Netherlands). In: Coastal Studies on the Holocene of the Netherlands (editors D.J. Beets, M.M. Fischer, W. de Gans). Mededelingen Rijks Geologische Dienst, Nr. 57, pp. 69-78.

González, Juan L., Törnqvist Torbjörn E., 2009. A new Late Holocene sea-level record from the Mississippi Delta: evidence for a climate/sea level connection? Quaternary Science Reviews 28 (2009) 1737–1749.

Grinsted, A., J. C. Moore, and S. Jevrejeva (2009), Reconstructing sea level from paleo and projected temperatures 200 to 2100AD. Clim. Dyn., doi:10.1007/s00382-008-0507-2.

Grinsted, Aslak, Jevrejeva, Svetlana and Moore, John C., 2011. Comment on the subsidence adjustment applied to the Kemp et al. proxy of North Carolina relative sea level. PNAS | October 4, 2011 | vol. 108 | no. 40 | E781–E782

Grinsted, Aslak, 2009-2013. Hindcasts using the Rahmstorf 2007 model

Grinsted - Publications in pdf-format

Hanisch, Jörg, 1980. Neue Meeresspiegeldaten aus dem Raum Wangerooge. Eiszeitalter und Gegenwart 30, 1980, 221-228.

Harff, J., M. Meyer unter Mitarbeit von: U. Cubasch, H. Dietrich , R. Lampe W. Lemke , H. Lübke , F. Tauber. Modellierung der Küstenentwicklung in der südwestlichen Ostsee. Stand: 15.02.2001 Projekt Ha1834/5-1 - Zwischenbericht -

Hofstede, J.L.A.1991. Sea Level Rise in the Inner German Bight Since AD 600 and its Implications upon Tidal Flats Geomorphology. In :Brückner and Radtke(Ed.) :Von der Nordsee bis zum Indischen Ozean, Franz Steiner Publ., Stuttgart.

Hofstede, J., 2007. Entwicklung des Meeresspiegels und der Sturmfluten: Ist der anthropogene Klimawandel bereits sichtbar? In: G. Gönnert, B. Pflüger & J.-A. Bremer Von der Geoarchäologie über die Küstendynamik zum Küstenzonenmanagement Coastline Reports 9 (2007), ISSN 0928-2734, ISBN 978-3-9811839-1-7 S. 139 - 148.

Jensen J., J.L.A. Hofstede., H. Kunz., Ronde, P.F. Heinen &W. Siefert.1993 .Long Term Water Level Observations and Variations. In : R.Hillen & H.J.Verhage n(Ed.) ,Coastlines of the southern NorthSea, ASCE, New York; 110-130 pp .

Jevrejeva, S., J. C. Moore, A. Grinsted, and P. L. Woodworth, 2008. Recent global sea level acceleration started over 200 years ago? GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L08715, doi:10.1029/2008GL033611, 2008

Kemp, Andrew C., Benjamin P. Horton, Jeffrey P. Donnelly, Michael E. Mann, Martin Vermeere and Stefan Rahmstorf, 2011. Climate related sea-level variations over the past two millennia, PNAS, Vol. 108, 11017-11022.

Kemp et al. Supporting information. PNAS, 2011, 14 pp.

Leverman, Anders, Peter U. Clark, Ben Marzeion, Glenn A. Milne, David Pollard, Valentina Radic and Alexander Robinson, 2013. The multimillennial sea-level commitment of global warming. PNAS, August 20, 2013, Vol. 110, no. 34, pp. 13745–13750.

Louters, T. en Gerritsen, F. 1994. Het mysterie van de wadden. Hoe een getijdesysteem inspeelt op de zeespiegelstijging. Rapport RIKZ-94.040, Ministerie van Verkeer en Waterstaat, Directoraat-GeneraalRijkswaterstaat, Rijksinstituut voor Kust en Zee/RIKZ, 70 pp.

Masters, Jeff, 2009. Sea level rise: what has happened so far?

Potsdam-Insititut für Klimafolgenforschung (PIK), Welcome to the sea level pages of PIK

Rahmstorf, S., 2011. 2000 years of sea level

Rosentau, Alar, Jan Harff, Tõnis Oja, Michael Meyer, 2012. Postglacial rebound and relative sea level changes in the Baltic Sea since the Litorina transgression. Baltica, Volume 25, Number 2, December 2012 : 113–120 doi:10.5200/baltica.2012.25.11

Thiede, J. und Ahrendt, K., 2000. Klimaänderung und Küste –Fallstudie Sylt. Teilprojekt: Klimabedingte Veränderung der Gestalt der Insel Sylt, Abschlußbericht, 2000, 53 pp.

Van de Plassche, O., Van der Borg, K., and De Jong, A.F.M. 1998. Sea level - climate correlation during the past 1400 years. Geology 26, 319-322.

Van de Plassche, O., G. van der Schrier, S. L. Weber, W. R. Gehrels, and A. J. Wright, Sea-level variability in the northwest Atlantic during the past 1500 years: A delayed response to solar forcing?, Geophys. Res. Lett., 30(18), 1921, doi:10.1029/ 2003GL017558, 2003

Van de Plassche, O, Bohncke, S.J.P., Makaske, B. and Van der Plicht, J. , 2005. Water-level changes in the Flevo area, central Netherlands (5300–1500 BC): implications for relative mean sea-level rise in the Western Netherlands. Quaternary International 133-134 (2005) 77–93.

Van de Ven, G., 1996. Turfwinning in Laag Nederland in de Middeleeuwen. Een inleiding op het thema en enige aspecten uit de geologische geschiedenis van
het kustgebied. Tijdschrift voor Waterstaatsgeschiedenis 5 (1996); webversie 2006, pp. 41-47.

Van Straaten, L.M.J.U., 1954. Radiocarbon datings and changes of sea level at Velzen (Netherlands). Geologie en Mijnbouw, Nwe Serie 16, 6, pp. 247-253.

Van Veen, J., 1945. Bestaat er een geologische bodemdaling te Amsterdam sedert 1700? Tijdschrift van het Koninklijk Nederlandsch Aardrijkskundig Genootschap. Tweede Serie, deel 62, pp. 2-36. 

Vermeer, M. and Rahmstorf, S.,  2009. Global sea level linked to global temperature. PNAS.

Vermeer, M., S. Rahmstorf , A. Kemp and B. Horton, 2012. On the differences between two semi-empirical sea-level models for the last two millennia. Clim. Past Discuss., 8, 3551–3581, 2012 doi:10.5194/cpd-8-3551-2012-print-1.pdf

Vermeer, M., 2012. Lange termijn zeespiegelstijging.

Weerts, H.; Cleveringa, P.; Westerhoff, W.; Vos, P. (2006): Nooit meer: afzettingen van Duinkerke en Calais, Archeobrief (Methoden en Technieken), 28-34. Stichting voor de Nederlandse Archeologie (SNA).