Climate crisis: Sea level rise will be faster than previously thought, scientists warn

University of Copenhagen study suggests oceans could rise 25 per cent higher than previous predictions

Scientists fear sea levels will rise more rapidly than previously thought, according to a new study which found current predictions have been too conservative.

The UN Intergovernmental Panel on Climate Change’s 2019 report estimated that, under a worst-case scenario, global mean sea levels will rise by up to a metre by 2100.

However researchers at the University of Copenhagen's Niels Bohr Institute now say that this prediction is significantly wide of the mark after they interrogated the IPCC models with historical data. 

Aslak Grinsted, associate professor at the University of Copenhagen's physics of ice, climate and earth department, was reticent to say by how much the sea level would rise as the paper does not make a future projection.

But he told the Mongabay website that the figure was “probably 25 centimetres per century higher than what we thought”. 

The study's results were published in the European Geosciences Union journal, Ocean Science, this week. 

Professor Grinsted said: "Apparently, the models we are basing our predictions of sea level rise on presently are not sensitive enough.

"To put it plainly, they don't hit the mark when we compare them to the rate of sea level rise we see when comparing future scenarios with observations going back in time."

As the planet heats up glaciers and ice sheets in polar and mountain regions melt, contributing to sea level rise.

Meanwhile, the oceans have been absorbing most of the excess heat from greenhouse gas emissions for decades. Water expands as it heats and so the quicker the ocean warms, the faster it will rise.

A new study from University of Copenhagen’s Niels Bohr Institute found the models to predict sea level rise are not sensitive enough (Aslak Grinsted, CC-BY)

The authors of the new study say that the IPCC sea-level models suffered in places because of limited data available to run tests. For example prior to satellite observations in the1990s, there was almost no data on how fast Antarctica was melting.

Professor Grinsted said their analysis used better historical data on sea level rise which "in principle, allows for a test of the combined puzzle of models".

Jens Hesselbjerg Christensen, a professor at the institute and co-author of the study, said that it was critical that models are as accurate as possible when it comes to future climate scenarios.

"We hope this new comparison metric will be adopted to as large extent as is possible and can become a tool we can apply in comparing different models," he said.

This article has been updated