Warning that melting ice could threaten many cities

Scientists say decline of frozen sheets could lead to big rise in sea levels and are a 'big cause for concern'

A study of the rapid decline of ancient ice sheets has left Scots scientists fearing climate change could lead to a rapid sea level rise.

Researchers at the universities of Stirling and Tromso in Norway have found conditions last seen 20,000 years ago are now being replicated in west Antarctica and Greenland.

The melting ice from the giant sheets is contributing to a steady rise in sea levels and the teams believe their findings could be a big cause of worry for many people.

These rising waters could have a catastrophic impact in the future on lowlying coastal regions where much of the planet’s population lives, endangering cites around the world.

All of this makes it vitally important to understand what is happening and the Scots and Norwegian teams believe their work will help scientists predict the impact of modern-day climate and sea level change.

Professor Alun Hubbard, who works at UiT Norway and Aberystwyth University, said: “Just like the Icelandic ice sheet some 20,000 years ago, the retreat of the Greenland ice sheet is now contributing up to approximately 1.2mm per year to global sea-level rise.

“That doesn’t sound much but given the timescales involved and that Greenland’s ice loss has increased from nothing 20 years ago to over roughly 350 cubic kilometres per year now, it makes it a significant cause for concern — particularly for those low-lying, coastal regions where much of the planet’s population lives.”

The groundbreaking research involved the creation of a detailed reconstruction of the evolution of the last ice sheet — massive land-based reservoirs of frozen water — which covered Iceland around 20,000 years ago.

It showed the greatest changes took place at a time when temperatures in the Northern Hemisphere rose by around 3°C in just 500 years.

The maximum rate of ice loss in Iceland then — including both ice melt and break-up of the mass as icebergs — was on the same scale seen in West Antarctica and Greenland today.

The Icelandic ice sheet reached a maximum size of 562,000sq km — an area about the size of France.

During its dramatic collapse the ice sheet melted rapidly over much of its surface area, decreasing in size by almost two-thirds in only 750 years.

This large volume of ice melting caused a 46cm rise in global sea levels — or more than 1mm rise every two years for more than seven centuries — and is equivalent to the ice losses being experienced in Greenland.

Greenland’s ice loss has increased from nothing 20 years ago to roughly 350 cubic kilometres per year now

Right: the model created by the universities of Stirling and Tromso shows the Icelandic ice sheet reducing in size between 22,000 and 11,000 years ago.