7 June 2017

Inaugural lecture of oceanographer Sybren Drijfhout on 22 June

Not a prophet of doom, but discoverer of second chances

Sybren Drijfhout

In 2015, Sybren Drijfhout was appointed as Endowed Professor of Climate Dynamics. His chair, the Buys Ballot Chair, is one of the endowed chairs at the Department of Physics & Astronomy, and is a part of the Institute for Marine and Atmospheric Research (IMAU). Drijfhout is a leading researcher in the field of climate dynamics, serving as Professor of Physical Oceanography at the University of Southampton. He is also affiliated with the  Royal Netherlands Meteorological Institute (KNMI). He will give his inaugural lecture in the University Hall on 22 June, focusing on sea level rise.

Drijfhout’s work is not limited to just studying the climate; he also draws links to policy and government. His message is occasionally difficult for people to understand, because what happens off the coast of the Netherlands is not necessarily the result of developments in global sea level. “Regional sea level rise is truly a field of its own”, Drijfhout explains. “Over the past 20 years, the sea level on the Dutch coast has risen less than average, but the rise in sea levels in the mid-North Atlantic has been above average. However, due to changes in ocean currents, I predict that the sea level on the Dutch coast will rise much faster in the next twenty years.”

Major problem

Rising sea levels at the regional and global levels are a big concern to Drijfhout. “Melting ice in Antarctica is a major problem. There is a delay in how fast the ice caps melt, so even if we stop global warming tomorrow, sea levels will continue to rise for hundreds to thousands of years to come.” Drijfhout tells about a new ice cap model that shows how in the worst-case scenario, the Dutch sea levels will rise by around three meters by 2100, and by perhaps as much as eight meters by 2200. “We don’t know exactly what consequences that will have for the Netherlands. But if we want to prepare our dikes to hold back a few meters of rising sea levels, we’ll need a hundred years of preparation. So we’re already behind schedule.”

With that kind of predictions, we’ll quickly face serious questions such as: can we hold on to the coastal provinces?

Prophet of doom

The Netherlands will definitely suffer the consequences of rising sea levels, Drijfhout says. “With that kind of predictions, we’ll quickly face serious questions such as: can we hold on to the coastal provinces? If we lose the island of Texel, then we’ll have serious problems.” By making statements like these, does he feel like a prophet of doom? “People sometimes call me that, yes. But my message isn’t entirely negative. The loss of mass from the ice caps progresses in stages, because there are several tipping points that dramatically accelerate sea level increases. In between those stages, sea levels are much less sensitive to rising temperatures. The connection between rising sea levels and temperatures is a bit like a stairway. Once you move from one step to another, you can stay there for a while, because there is a temperature interval that gives you time to limit further sea level increases, as long as you don’t pass the next tipping point - the next step on the stairs.”

Hundred meters

To get back to the counter-intuitive message for policymakers: how is it possible for sea levels in different places to rise at different rates? “You can’t compare sea level to the surface of water in a bucket”, Drijfhout explains. That is due to the shape of the earth, ocean currents, and the gravity of large land masses. “When you sail from Barcelona to Istanbul, you move about 100 meters upwards and downwards relative to the centre of the earth. And if you were to move the Himalayas to the province of Gelderland, then Amsterdam would be dozens of meters under water. Phenomena like those make sea level rise a very complicated story.”

Sybren Drijfhout

Prof. Sybren Drijfhout (1957) studied Physics in Utrecht, with a specialisation in Meteorology. He earned his PhD under Prof. Wil de Ruijter at the IMAU. Since 1995, he has been affiliated with the Royal Netherlands Meteorological Institute (KNMI) as a Senior Researcher. In 2013, he was appointed to the position of Professor of Physical Oceanography at the University of Southampton. Prof. Drijfhout’s duties at Utrecht University include teaching as well as research.

Contact and press requests

Nieske Vergunst, press officer Faculty of Science, +31 6 2490 2801 or N.L.Vergunst@uu.nl.
Press communications Utrecht University, +31 30 253 9300 or news@uu.nl.

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