Researchers from Imperial College London and colleagues studying mud samples to learn about ancient melting of the East Antarctic ice sheet found melting took place repeatedly between 5 million and 3 million years ago, during a geological period called Pliocene Epoch, and pushed up global sea levels.
The findings may provide insights into how sea levels could rise as a consequence of current global warming, an ICL release said Monday.
"The Pliocene Epoch had temperatures that were two or three degrees higher than today and similar atmospheric carbon dioxide levels to today," Tina Van De Flierdt of the college's Department of Earth Science and Engineering said.
"Our study underlines that these conditions have led to a large loss of ice and significant rises in global sea level in the past. Scientists predict global temperatures of a similar level may be reached by the end of this century, so it is very important for us to understand what the possible consequences might be."
The East Antarctic ice sheet, roughly the size of Australia, is the largest ice mass on Earth.
The findings of the Pliocene melt contradict long-held assumption that the size of the ice sheet stabilized around 14 million years ago.
"Scientists previously considered the East Antarctic ice sheet to be more stable than the much smaller ice sheets in West Antarctica and Greenland, even though very few studies of East Antarctic ice sheet have been carried out," researcher Carys Cook said.
"Our work now shows that the East Antarctic ice sheet has been much more sensitive to climate change in the past than previously realized. This finding is important for our understanding of what may happen to the Earth if we do not tackle the effects of climate change."