A May 20 Sentinel-2 satellite image shows the Dutch province of Zealand, including the port of Rotterdam, the largest seaport in Europe, in the upper right. Much of the region is below sea level and is based on a complex system of dikes, canals and dams for survival.
Credit: European Space Agency
Credit: European Space Agency
Climate change is causing oceans to rise faster than scientists ’most pessimistic forecasts, leading to previous flood risks for coastal economies that are already struggling to adapt.
The revised estimates were released Tuesday at Ocean science they affect two-fifths of the Earth’s population living near the coasts. Billions of dollars worth of insured assets could face even greater danger from floods, storms and tidal waves. Research suggests that countries will need to curb their greenhouse gas emissions even more than expected to keep sea levels under control.
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“It means our carbon budget is even more depleted,” said Aslak Grinsted, a geophysicist at the University of Copenhagen who co-authored the research. Economies need to reduce an additional 200 billion metric tons of carbon (equivalent to about five years of global emissions) to stay within the thresholds set by previous forecasts, he said.
The hotter it gets, the faster the sea level rises. Future sensitivity models seem incompatible with historical data.
Credit: Aslak Grinsted
The researchers relied on the models of the United Nations Intergovernmental Panel on Climate Change, many of which have only been considered for the past 150 years, incorporating data dating back several centuries. New observations show about a half-meter rise in the sea by the end of the century that can now be expected with only a rise in temperatures of 0.5 degrees Celsius. The oceans could rise more than a meter to 2 degrees Celsius, a trajectory that will easily pass under the current climate policies.
“The models on which we base our predictions on sea level rise are currently not sensitive enough,” Grinsted said. “To put it bluntly, they don’t touch the mark when we compare them to the rate of sea level rise we see when comparing future scenarios with observations that go back in time.”
The findings follow last month’s warning that rising temperatures have melted 28 trillion metric tons of ice, equivalent to a 100-meter-thick layer of ice covering the entire UK, making climate scenarios more likely at worst. The new methodology for monitoring sea level change could help insurance companies, real estate developers and planners to erect tidal defense systems.
“The scenarios we see ahead of us on sea level rise are too conservative: the sea seems, by our method, to rise more than is believed with the current method,” Grinsted said, adding that his team of the Niels Bohr Institute is in contact with the IPCC to incorporate its results in the sixth edition next year Evaluation report.