The Medieval Warm Period (MWP) or Medieval Climatic Anomaly was a time from about 950 to 1250 when climate was warmer than in the timespans immediately before and after.

My question is if this warming lead to significant changes in sea level and how these looked like around western Europe, how the sea levels developed during this time.

Since the change in temperature was not globally uniform, it is of course possible that the sea level changes didn't amount to much.


In the global sense the sea level data are not entirely consistent, but then, there are always going to be apparent variations when you are comparing proxy data from different sources. As far as Europe is concerned sea level rose between 1.0 and 1.6 metres throughout the Medieval Warm Period - or maybe as much as 2.0 metres by some of the more extreme estimates. Following this was the 'little ice age' (actually not an ice age at all), when sea level fell by almost as much. See for example the graphs of Behre 2004, and Puls, 2008, (German North Sea coast),both of which are reproduced in Kwaad's paper, which is a good overview.


Whatever sea level change you regard as definitive, the important point is that these were just minor variations superimposed upon a major sea level trend. Overall the post-glacial sea level, from about 8000 years ago, was a rapid rise from -50 metres (or so), flattening off during the last two millennia, and now massively accelerating again, primarily due to human-induced climate change.

  • 2
    $\begingroup$ How did you arrive at 2m? the extreme points in the Klaus Eckart Puls 2008 chart? $\endgroup$
    – mart
    Jun 21 '16 at 14:58
  • $\begingroup$ I doubt that sea-level rose as much as 1m during the MWP. The Kwaad web page to which you linked says, "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." There were no tide gauges a thousand years ago, but, from the history of places like Pevensey Castle and Ephesus, it seems unlikely that sea-level rose that much during the MWP. $\endgroup$ May 28 '18 at 18:15
  • $\begingroup$ You can check coast line in this webpage for 2 meters: floodmap.net $\endgroup$
    – user12525
    Mar 2 '19 at 16:00

This article based on 2016 publications shows a global decline during 950 to 1250. enter image description here

Fig. 1 Reconstruction of the global sea-level evolution based on proxy data from different parts of the world. The red line at the end (not included in the paper) illustrates the further global increase since 2000 by 5-6 cm from satellite data.

There may be local differences due to isostatic rebound but these happen on much longer timescales.

  • $\begingroup$ I can't see in the Kwaad paper the large increase suggested by @GordonStanger . $\endgroup$ Mar 2 '19 at 20:26
  1. The Tower of London was built during this period on the banks of the Thames River level is the same today as it was then.
  2. People seem to forget that the Anasazi in SW America disappeared during this same period due to prolonged drought so there was no food to eat.
  3. The Chinese also have three hundred years of weather records recording changes in their weather as well. Particularly, an increase in rainfall during the peak of the European temperature increases.
  4. Tree rings in North American West show a slow down in growth. So when “warmers” try to say that the weather changes during this period of time was a local occurrence they, as usual, don’t know what the hell they are talking about.
  • $\begingroup$ Sources please. $\endgroup$
    – John
    Jul 19 at 2:09

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