CAUSES OF 30 YEARS OF SEA LEVEL RISE WORLDWIDE IDENTIFIED

Causes of 30 years of sea level rise worldwide identified. Sea levels are rising almost everywhere on Earth. Satellites measure this very precisely. Sea level rise along the world’s coasts is caused by a combination of different factors. Some factors will play a stronger role than others in the coming decades. PhD student Carolina Camargo has used observations of the different contributions to map per region what has caused local sea level rise over the last 30 years. With this knowledge, coastal areas around the world can better prepare for the sea-level rise still to come.

Sea levels are changing around the world. To protect people along the coast, we rely on sea level projections – predictions of how much the sea level will rise in the future. The models of these projections are a representation of the physical processes that cause the sea level to change. “For example, think about changing the volume of water as it gets saltier, fresher or warmer,” Camargo said. “But sea level is also rising because land ice is melting in the polar regions. And then you can expect regional sea level change due to changes in more dynamic systems such as weather, ocean currents and changes in the mass distribution on our planet.”

Camargo has used observations from many different physical changes that add to sea level change and compared these to the total changes observed by satellites. Camargo’s main finding was that smartly chosen areas must be looked at to investigate local sea level rise. Camargo: “if we look at a very specific point on the coast, then the comparison does not work well because the physical processes take place on a larger scale. The current study is a proof-of-concept to discover at what scale we can best look at coasts to properly map the driving forces behind local sea level rise.”

Better preparations

Carolina Camargo’s research can help improve coastal protection in the face of climate change. For example, monitoring the drivers of local sea level change can be used as an early warning signal for accelerating sea level rise. With this, local policies can be developed in which coastal areas adapt to higher sea levels. “For example, we see that variations in ocean mass through the melting of the Antarctic ice sheet is an important contributor to current sea level change along the Western European coastline,” Camargo said. “So, if an acceleration is observed in melting of the Antarctic ice sheet, then perhaps adaptation policies in this region should be accelerated.”

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