THE rapid decline of ancient ice sheets could help scientists predict the impact of modern-day climate and sea-level change, according to research by the universities of Stirling in Scotland and Tromsø in Norway.

For the first time, scientists have reconstructed in detail the evolution of the last ice sheet to cover Iceland around 20,000 years ago.

The recently published study shows 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 was on the same scale seen in West Antarctica and Greenland today, providing evidence of how climate change can dramatically alter the world’s ice sheets and lead to rapid sea level rise.

Dr Tom Bradwell, from Stirling’s Faculty of Natural Sciences, said: “About 22,000 years ago, the climate awoke from the last Ice Age, and entered a prolonged but gradual period of warming. This triggered the melting of the huge ice sheets that once covered North America and Eurasia.

“We used seafloor data to map the full extent of the last Icelandic ice sheet and fed this geological information into our ice sheet model. The new modelling experiments, driven by climate data from Greenland ice cores, replicate ice sheet behaviour over the last 35,000 years, showing when it melted the fastest and how it behaved.

“We found that, at certain times, the Icelandic ice sheet retreated at an exceptionally fast rate – more than double the present-day rate of ice loss from the much larger West Antarctic ice sheet – causing global sea level to rise significantly.”

These high-resolution model experiments, published in Earth-Science Reviews, provide an unprecedented view of how the Icelandic ice sheet rapidly reduced in size and volume between 21,000 and 18,000 years ago, mainly through icebergs breaking away from its marine margins.

It then collapsed 14,000 years ago, this time abruptly in response to rapid climate warming.