Kerem Yucel / AFP via Getty Images
During the Earth’s ice age, much of North America and Northern Europe was covered by large glaciers.
About 20,000 years ago, those ice sheets began to melt rapidly, and as a result the water had to go somewhere – usually underneath glaciers. Over time, large valleys form beneath the ice to drain water from the ice.
A new study of how glaciers melted after the last ice age could help researchers better understand how today’s ice sheets might respond to the extreme warmth caused by climate change, the researchers said. said the study’s author.
The study, published this week in the journal Quaternary Scientific Reviewhelped clarify how – and how quickly – those channels were formed.
“Our results show for the first time that perhaps the most important mechanism is summer melting on the ice surface, which reaches the buffer through cracks or chimney-like ducts and then flows under the pressure of the ice sheet to cut,” said Kelly Hogan, co-author and geophysicist at the British Antarctic Survey.
Researchers find thousands of valleys under the North Sea
By analyzing 3D seismic reflection data originally collected through risk assessments for oil and gas companies, researchers found thousands of valleys in the North Sea. Those valleys, some of them millions of years old, are now buried deep in the mud of the seabed.
Some of the canals are huge – up to 90 miles wide and three miles wide (“many times bigger than Loch Ness,” UK-based research team noted).
James Kirkham / British Antarctic Survey
What surprised the researchers most, they said, was how quickly those valleys formed. As ice melts rapidly, water has created valleys for hundreds of years – at lightning speed, geologically.
Lead author James Kirkham, a BAS and Cambridge University researcher, said: “This is an exciting discovery. “We knew that these spectacular valleys were carved out during the deadliest age of the ice sheets. Using a combination of modern subsurface imaging techniques and computer modeling, we learned that we were there. found that tunnel valleys can erode rapidly beneath extremely warm bed sheet ice,”
Melting water channels are traditionally thought to stabilize ice melt, the researchers say, and by expanding sea level rise, by helping to cushion the collapse of ice sheets, researchers say. research said.
New findings could complicate that picture. However, the rapid rate at which channels form means that including them in today’s models could help improve the accuracy of current ice sheet melting predictions, the authors say. more.
Today, only two large ice sheets remain: Greenland and Antarctica. The speed at which they melt likely to increase as the climate warms.
“The key question now is whether this ‘extra’ meltwater causes our ice sheets to flow faster, or slower, into the sea,” Hogan said.