Nancy Bertler and her team took a freezer to the coldest place on Earth, endured weeks of primitive living and risked spending the winter in Antarctic darkness, to go get ice — ice that records our climate’s past and could point to its future.
They drilled out hundreds of ice cores, each slightly longer and wider than a baseball bat, from the half-mile-thick ice covering Antarctica’s Roosevelt Island. The cores, which may total 150,000 years of snowfall, almost didn’t survive the boat ride to New Zealand because of a power outage.
Ms. Bertler hopes the material will help her estimate how long the Ross Ice Shelf would last under the current rate of climate change before falling apart.
Evidence from the last core her team hauled out needs further study, but it contains material that Ms. Bertler said appeared to be marine sediment that formed recently — at least in geological terms measured in thousands of years.
That would bolster scientists’ suspicions that the shelf could collapse again if global temperatures keep rising, triggering a chain of events that could raise sea levels around the world.
“From a scientific point of view, that’s really exciting. From a personal point of view, that’s really scary,” said Ms. Bertler, a senior research fellow at the Antarctic Research Centre at the Victoria University of Wellington.
The ice shelf acts as a natural barrier protecting massive amounts of ice in West Antarctica, and that ice also could fall into the ocean if the shelf fell apart.
Scientists say West Antarctica holds enough ice to raise sea levels by between two metres and six metres if significant parts of it were to melt and collapse.
Ms. Bertler hopes the material she recovered will help her to estimate by the end of this year whether it will take 50 years or 500 years for the ice shelf to collapse at the current rate of climate change.
Those answers should prove important for policymakers who, she said, may need to decide whether to build sea walls or move populations to higher ground.
Ms. Bertler’s project is one of scores that take place on Antarctica every Southern Hemisphere summer. To scientists, the continent’s pristine habitat offers a unique record of the planet’s weather and a laboratory for studying the effects of climate change.
Studies indicate that while the Arctic has suffered what scientists consider to be alarming rates of ice loss in recent years, the Antarctic ice shelf has remained relatively stable despite having have lost ice in recent decades.