Because ocean water washes up against the leading edge of the ice, the grounding line can be a zone of rapid melting. Today, the Ross Ice Shelf extends hundreds of miles over the ocean from the grounding line of the West Antarctic Ice Sheet. The grounding line is where a glacier or ice sheet leaves solid ground and begins to float on water as an ice shelf. It presents the first geologic constraint for the ice sheet’s location and movement since the last ice age. The study appears in AGU Advances, which publishes high-impact, open-access research and commentary across the Earth and space sciences. “The ongoing retreat of Thwaites Glacier is much faster than we’ve ever seen before, but in the geologic record, we see the ice can recover.”
“In the last few thousand years before we started watching, ice in some parts of Antarctica retreated and re-advanced over a much larger area than we previously appreciated,” said Ryan Venturelli, a paleoglaciologist at Colorado School of Mines and lead author of the new study. New research finds that 6,000 years ago, the grounded edge of the ice sheet may have been as far as 250 kilometers (160 miles) inland from its current location, suggesting the ice retreated deep into the continent after the end of the last ice age and re-advanced before modern retreat began. WASHINGTON - The West Antarctic Ice Sheet is melting rapidly, raising concerns it could cross a tipping point of irreversible retreat in the next few decades if global temperatures rise 1.5 to 2.0 degrees Celsius (2.7 to 3.8 degrees Fahrenheit) above preindustrial levels. Ryan Venturelli, Colorado School of Mines, (UTC-7 hours) Scientists traced the ice’s movement using sediments from a lake more than 1 kilometer (0.6 miles) under the ice, sampled using the corer in this photo.
The West Antarctic Ice Sheet retreated at least 250 kilometers (160 miles) inland of where the ice meets the ocean today, then re-advanced, according to new research published in AGU Advances.
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