Scientists get clues on climate change by looking back to Ireland’s Ice Age

National Seabed Survey provides “invaluable” data

Irish scientists are looking back hundreds of thousands of years to Ireland’s last ice age in order to better understand the climate changes happening within the country today. Their research has also helped determine why Ireland’s topography is the way it is, according to the Irish Times.

Research is focusing on analyzing the continental seabeds not only off the coast of Ireland, but as far away as Antarctica in order to piece together the creation of Ireland’s varied topography, and provide clues into climate shifts.

Dr. Paul Dunlop, head of the Quaternary Environmental Change Research Group at the University of Ulster, Coleraine, and his team have been studying the period of the past 120,000 years, the timeframe of when the last ice age came and went.

In particular, that period featured a kilometer-deep ice sheet that blanketing Ireland during that when analyzed, can unlock some of the secrets to the climate changes - including temperatures and timing of the shifts.

“The Quaternary [the period the team is studying] is characterised by climate change, and this caused changes in the ice sheets,” says Dunlop.

Not surprisingly, Dr. Dunlop and his team were faced with no easy feat. “The problem with the ice sheets is they are so destructive they destroy all the evidence of past glaciations. It is very difficult to get information on previous ice sheets. The deeper you go back in geological time the more vague it becomes.”

Dr. Dunlop was working out of NUI Galway when an ambitious project to map the seabed was underway. The program set out to map all of Ireland’s extensive continental shelf out to the edge of the deep Atlantic waters and beyond.

Dr. Dunlop said that “The big unknown question was: how far out did the ice sheet extend?” Through their research, the team was able to determine that the sheet extended for many kilometers, and in some cases, out to the edge of the continental shelf.

“The most striking features we see are the ridges, 10 km long. We have definitely mapped the western extent of the ice sheet.” One of the biggest ridges found was 14m high, 125km long and 11km wide.

“There are also features gouged into the seabed, icebergs ploughing up the sea floor.”

One trend the scientists noticed was that the ridges are seen closer and closer to the coastline, retreating as the climate warmed and the ice began to melt.

“This gives us a nice high-resolution data set on climate change. It shows you what the footprint was as it retreated and how rapidly it retreated,” Dr. Dunlop said.

By conducting radiocarbon dating on the species that would have occupied the cold-water that was advanced when the ice retreated, Dr. Dunlop was able to provide a date for the furthest extent of the ice, placing it between 29,000 and 27,000 years ago.

Similarly, cosmogenic radionuclide dating can also be used to track the land-based retreat of the ice.

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Nster.com