By Bryce Gray –
Clues unearthed from the northernmost caves on the planet could help plug a 10,000-year gap in Greenland’s ice core record, providing essential information about where the climate may be heading now.
But perhaps spelunking climatologist Gina Moseley’s most shocking discovery from this past summer’s expedition was the abandoned army rations that expired 60 years ago yet turned out to be edible.
Moseley, a post-doctorate fellow at the University of Innsbruck in Austria and the leader of the Northeast Greenland Caves Project, hopes that data retrieved from the expedition will provide climate scientists with eye-opening climate information where ice cores fall short.
“The cave records from Greenland are going to complement the Greenland ice cores,” said Moseley. “It’s completely new information for Greenland that we don’t have yet.”
So far, the cave findings are promising.
“We’ve got the preliminary results and they’re very positive,” said Moseley. “We can date the samples, we can see a climate record in them.”
As millennia of climate records melt away with the world’s glaciers, speleothems – the term for cave formations such as stalagmites and stalactites – are increasingly coveted sources of climate data. In 2006, Oxford-based climate scientist Gideon Henderson wrote in the journal, Science, that: “For paleoclimate, the past two decades have been the age of the ice core. The next two may be the age of the speleothem.”
Like ice cores or tree rings, the drip-by-drip accumulation of water-deposited minerals over time reveals high-resolution information about long-term trends in the surrounding environment. By studying the geochemistry of speleothems formed by water percolating through the soil and atmosphere above, scientists can reconstruct the timing of past trends related to temperature, moisture and vegetation for a given area.
Speleothems were a hot topic of conversation at the Comer Abrupt Climate Change Conference earlier this fall, where Moseley and several other scientists presented some of the latest research from the caves.
“Ice cores are restricted to high latitudes or high altitudes generally, but caves can give us information that’s equally precise and high-resolution,” Moseley said.
In the remote backcountry of northeast Greenland – within 10 degrees latitude of the North Pole – Moseley and her five team members seized a rare opportunity to conduct cave research in a setting where ice core records are also available.
“Typically most of your cave records come from the tropics and mid-latitudes, so that’s why the Greenland project is a bit unique. It’s a cave record from a site where you’ve also got the ice cores,” said Moseley.
Twenty-six caves later, Moseley said she is hopeful that findings of the project also will bridge the gap in the existing ice core records, which stretch back to the last interglacial period occurring 130,000 to 118,000 years ago.
“The Greenland ice cores are very high-resolution records, but they’re limited (to) the last 123,000 years,” said Moseley. “Those ice cores tap into the last time that the Earth was warm – the last interglacial.”
But deeper into the interglacial period, the era’s warm temperatures interrupted ice preservation. Speleothem records, however, should not have fallen victim to the same disruption and, as a result, could contain valuable information about what to expect from a warmer climate.
Moseley said that during the last interglacial period, Greenland was warmer by 3-5 degrees Celsius (5.4-9 degrees Fahrenheit). Although scientists are unsure of the reason for the elevated temperature, climate data from that era could provide a glimpse of what currently warming temperatures might have in store for the region.
“That might have implications for what might happen in the future with a warmer world,” Moseley said.
Moseley’s team found more than just speleothems in their adventurous search. They were greeted by the remains of a dead polar bear at the end of a remote landing strip, as well as a frozen bird carcass that couldn’t be identified as any species currently found in the area.
Perhaps most memorably, the team also stumbled across a long-forgotten pile of canned U.S. army rations. Curiosity, and dwindling food supplies, got the better of them, as Moseley and her colleagues bravely cracked into a tin of crackers and jam – among other morsels – despite an expiration date of September 1955 printed on the lid.
“It tasted fantastic,” Moseley reported. “The biscuits were a little dry, but otherwise OK. The jam went really well with our porridge.”
She said that one of her partners mustered the courage to try a tin of meatballs and beans.
“He said they were great and there were no side effects,” Moseley said.
Now back in the lab and continuing to refine the precision of the cave data, Moseley is working to understand the broader significance of the story told by the speleothems.
“It’s all very well, producing the record, but then you need to interpret what it means and what it’s recorded,” Moseley said.
Determining that would leave an even more satisfying aftertaste than canned army rations.
Dec. 16, 2015
Photo at top: This summer, team members of the Northeast Greenland Caves Project took to the world’s most northerly explored caves to collect climate data. (Courtesy of the Northeast Greenland Caves Project)