Scientists Have Underestimated Sea level Rises – Models are Failing

The average sea level is 30 cm higher than previously thought. In some places, such as Southeast Asia, it is even higher, up to one and a half metres. New research has shown that previous calculations of sea levels were based on incorrect models that gave misleading results.

^{Text: Lena Scherman}

Rising sea levels pose a major threat to coastal communities around the world. Floods are becoming more frequent, coastlines are eroding, and insurance companies are refusing to insure properties. We can also expect migration inland. Everyone will be affected. That is why it is important to be able to make reasonably accurate estimates of how much sea levels will rise in the future. New research now shows that previous calculations were completely wrong because they were based on incorrect models.

The authors of the new report, published in Nature, Dr Philip Minderhoud from Wageningen University in the Netherlands and PhD student Katharina Seeger, discovered that more than 90% of previous studies used land elevation measurements referring to global geoid models instead of local, direct measurements of sea levels.

Geoid models provide an estimate of global sea levels based on the Earth’s gravity and rotation.

As a result, sea levels were underestimated by an average of 24–27 cm, depending on the model used, with some deviations as high as 550–760 cm.

The researchers describe the differences in the calculations as an ‘interdisciplinary blind spot’ and have expressed concern that so many of the studies they analysed that proved to be incorrect are referenced in the latest climate change reports published by the IPCC.

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