Sea levels along Dutch coast rising faster: Delft researchers

The rise of sea levels along the Dutch coast is accelerating, scientists from TU Delft report. They based this on an analysis of measurement data from tidal stations from Delfzijl to Vlissingen.

Since the mid-1990s, the water level off the Dutch coast has risen significantly faster than in the previous 70 years, the researchers conclude. Since then, the sea level has increased by an average of 2.7 millimeters per year. Due to uncertainty in the data, that average rise may be 0.4 millimeters higher or lower. In the seven previous decades, sea levels rose between 0.5 and 1.5 millimeters per year.

It is a well-established fact that sea level rise is accelerating worldwide due to global warming. According to TU Delft, this is the first time that “a significant acceleration” has been discovered in the data from the Dutch tidal stations along the North Sea.

The researchers see significant differences per station. For example, the rise in sea level in the Wadden Sea is twice as fast as elsewhere. Also, in the course of a year, the water level can differ greatly from one monitoring station to another. As a result, it is not easy to find such an acceleration in the figures.

The eight monitoring stations have existed for over 100 years and are relatively close to each other. “Nowhere in the world can you find such a good dataset,” said researcher Riccardo Riva. To what extent we should be concerned is “a question for politics,” he said.

Worldwide, the sea level has risen about 20 centimeters since the beginning of the 20th century. The UN panel of client scientists IPCC concluded last year that the previous 30 centuries had never seen such a substantial increase. In the next thirty years, sea levels will rise another 20 centimeters and continue higher after that, the IPCC expects. This could have major consequences for a country like the Netherlands, which is 26 percent below sea level.

Climate scientists attribute the increase to the melting ice in Greenland and the polar regions and an expansion of the ocean water. Because the world gets warmer, the top layer of the water heats up. As a result, the volume of that water increases, resulting in higher water levels.