Highest sea levels at Dutch coast in recorded history

In 2017 the average sea level was 11cm above the NAP (Normal Amsterdam's Peil). That is 2cm higher that the former record year, 2007. 
Fedor Baart, spokesperson of the research institute Deltares explained the phenomenon to newspaper de Volkskrant.

The sea level expert explained that the record is not surprising at all: "Since 1890 the waters along the coasts are rising about 2mm per year, because of the melting of the polar ices and the glaciers, together with the rise in temperature of the seas."

Another minor factor involved in the water levels rise is the subsidence, the sinking of the ground. "So actually you should expect a high sea level record every year", he adds. 

Baart also reassures that the level is not rising faster than normal, like it would seem form the figures. The sudden raise can be explained by the fact that the Netherlands has not had many sea storms in the past years. 2017's more frequent storms caused peaks in the water level, which increased the average. 

Water levels and their rising are not equal in the whole world. The surface of the see can vary of about 200m, Sybren Drijfhout, oceanographer by the KNMI, told the Volkskrant. Ocean currents, gravity, the moon, the temperature and the salt content cause those different levels.