Observations confirm computational model predictions of sea-level rise

A team of scientists at the Los Alamos National Laboratory in the US has analysed the ‘fingerprint’ of sea-level change attributable to the melting of the Greenland ice sheets.

By analysing high-resolution satellite observations, the team was able to confirm the predictions made using theoretical and computational models of sea-level changes to forecast climate-change-driven impacts.

“Using sea-surface-height observations from satellites in the way we have independently verifies observations of Arctic and Greenland ice-mass loss and allows us to tease apart contributions to global sea-level rise from individual ice sheets and glacier systems,” said Sophie Coulson, a postdoctoral researcher at Los Alamos National Laboratory.

Global warming has significantly increased the likelihood of extreme weather events, and scientists have, for decades, warned about the dangers of sea-level rise caused by the melting of the ice sheets. Therefore, accurate predictions of regional sea-level change are essential in understanding the impact of climate change on coastal areas, which are the areas most threatened by this phenomenon.

However, sea level rise is notably difficult to predict. As the ice sheets melt, the resulting water is redistributed around the global oceans, but the sea level does not rise uniformly. Moreover, every glacier and ice sheet has a unique pattern of sea-level change, which have come to be known as sea-level fingerprints.

But despite over half a century of research, these fingerprints have never been unambiguously detected, according to the researchers. 

Coulson’s research focused on satellite observations of sea-surface height in the oceans surrounding the Greenland ice sheet over the last three decades. The dominant effect in this region is that as the Greenland ice sheet loses mass, it exerts less gravitational attraction on water in the open ocean and so water migrates away from the ice sheet.

This results in a lowering of sea level near Greenland, but progressively higher levels of sea-level rise outside the region.

To confirm their suspicions, the research team used processed satellite observations that extend to much higher latitudes than previously possible, where the fingerprint signal is the largest.

“We predicted what the pattern of sea-level change would be around Greenland using new estimates of ice melting in the area,” Coulson said. “When we then compared this pattern to satellite observations of sea-level change the fit was remarkable. It was an incredible eureka moment for us when the team saw it — ‘there it is, the sea-level fingerprint!’”

There is broad consensus among scientists that even if the greenhouse gas emissions that warm the Earth are dramatically cut, global sea levels will continue to rise for several hundred years. 

When it comes to the impact on the UK, experts have predicted England could face around 35cm (14in) of sea-level rise compared to historic levels by 2050 and is nearly certain to see close to 1m (3ft) of sea-level rise by the end of the century.

A recent study published in the journal Oceans And Coastal Management has concluded that nearly 200,000 homes and businesses in England are currently at risk of being lost forever to the seas, while conservation charity English Heritage has issued a warning regarding the danger that climate change poses to the survival of several castles on the UK coastline, some of which have stood for hundreds of years. 

The Los Alamos National Laboratory researchers published their findings in a paper in the journal Science.