With drilling limited to warmer months and several setbacks along the way, it took seven years to reach the bottom of the ice cap. “The purpose of this drilling is to study how warm periods end, because we are in a warm period right now,” said Sigfus J. Johnsen, chief driller of the North Greenland Ice Core Project, or North GRIP.
Modern Earth is 11,500 years into a warm period, which typically lasts only 10,000 years, Johnsen said. This raises obvious important questions about the future of civilization as we know it: In the last Ice Age, glaciers reached as far south as modern-day New York City.
The North GRIP team’s drill reached bedrock at 3:15 p.m. CDT Thursday, setting off ecstatic cheers in the tent city on the endless white ice far above the Arctic Circle. They gathered around the muddy brown core as Johnsen poured champagne and led a toast to their $6.4 million project. The final feet of ice from the core will be carefully measured, packed, and shipped to the University of Copenhagen over the next few weeks.
When the ice core finally arrives in Copenhagen, scientists will need years to fully analyze it. They will measure levels of oxygen isotopes, study the gases trapped in microscopic air bubbles, and look for tiny bits of prehistoric dust literally frozen in time. With those scraps of evidence, they can determine what the temperature was at the North GRIP site for every single summer and winter going back at least 120,000 years.
As further reported by the New York Times, the final core sample pulled up from the ice showed an unexpected surprise. The very last sample from the bottom of the ice sheet included a tan icicle, about the size of a roll of paper towels, hanging from the drill. The researchers think the drill penetrated a pocket of water at the very bottom of the ice sheet.
They knew the bottom was warm, heated by geothermal energy in the underlying rock, but they did not expect to be able to sample it. But it appears that the liquid spurted up and froze solid to the drill bit, which had passed through much cooler ice on the way down. The pocket of water could have been covered ever since the ice sheet was first formed, millions of years ago.
“I couldn’t believe my eyes,” said Dr. Dorthe Dahl-Jensen, the project’s chief scientist. “It could contain evidence of ancient life.”