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Purdue researchers hope Antarctic rocks hold clues about climate future

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Marissa Tremblay and her team traveled to the McMurdo Dry Valleys for rock samples they hope will give them clues about ancient Antarctic temperatures. (Photo courtesy of Purdue University/Marissa Tremblay).

A team of Purdue University researchers traveled to Antarctica last year to study the Earth’s climate in the deep past.

Scientists hope rocks from the continent could paint a picture of temperatures in the region nearly three million years ago, when sea levels were more than 50 feet higher than today.

During the mid-Pliocene era, levels of atmospheric carbon were similar to current amounts. That makes the time period an important one for climate scientists to study because it might tell us about the climate’s direction in the coming decades and centuries.

Purdue scientist Marissa Tremblay said researchers want to understand how warm Antarctica was in that era because it could reveal the impact on ice sheets covering the region right now.

“We’re really interested in what the past climate of polar regions was like, because these are places that have ice sheets today that we know are going to be sensitive to ongoing climate change,” she said. “We look to Earth’s climatic past to try and understand how sensitive these regions are to the warming that they are going to experience. That’s sort of the big picture motivation.”

Specifically, knowing how much warmer Antarctica was during that period might give scientists a clue about how much warming our modern-day ice sheets can withstand.

“If we know that there was x amount of melting that happened, did that melting happen with just a few degrees of warming?” Tremblay said. “Or was Antarctica a lot warmer? That would mean that the ice sheets are a lot more robust than we currently think.”

Tremblay and her team worked at the McMurdo research station, which is home to over 1,000 residents and the largest community on the continent. From there, Tremblay and her all-women team made trips into the McMurdo Dry Valleys searching for rocks.

Tremblay herself developed a way of analyzing rocks that helps scientists extrapolate the temperatures those rocks have experienced.

Erosion in most regions of the planet happens too quickly for rocks to be a reliable temperature gauge from three million years ago, but Tremblay said within the McMurdo Dry Valleys, rocks have been sitting at the surface for periods of up to 10 million years.

“One thing that’s special about the part of Antarctica that we’re in is these rocks have been sitting at the surface for a really, really, really long time,” she said.

The rocks collected by the research team haven’t made it back to Purdue yet, but Tremblay said she expects them to ship out from Antarctica sometime in February. Once the rocks arrive, Tremblay and her team will begin the work of trying to understand Antarctic temperatures – and what they could tell us about our own future.

“Depending on which emissions projections you look at, we might be heading towards a lot of warming anyways,” Tremblay said. “But it would be nice to know how much warming corresponds to how much ice lost – that’s the big picture goal. That’s helpful for the future, whether or not we warm a little bit or a lot.”