ANCHORAGE - For the first time in decades, federal officials allowed drilling in the Arctic National Wildlife Refuge this summer.
It wasn't for oil, though.
The drillers were targeting ice buried deep in a glacier high in the Brooks Range.
Their goal is to learn about the region's past climate and search for clues about the region's future.
One pressing question: If the few Brooks Range glaciers dry up - and it seems likely that they will if the current warming trend persists - what will happen to the coastal plain rivers they feed?
Despite all the recent interest in climate change in the Arctic, there's little data on historical climate change in this swath of the Arctic.
"We're barely measuring what's happening now," said Matt Nolan, a glaciologist at the University of Alaska Fairbanks who led the ice core drilling project this summer.
In other places where there's no written record, scientists can drill into trees to study their rings. But there are few trees in that part of the Brooks Range.
Scientists also can analyze sediment layers drilled from lakes, but there aren't that many lakes there either.
One thing the region does have is a scattering of small glaciers. Ice cores drilled out of glaciers are one of the most valuable tools used by climate researchers around the world today to study temperature changes over hundreds and even thousands of years, Nolan said.
On the Greenland ice sheet, for example, scientists have used ice core samples to probe annual temperature fluctuations as long ago as 100,000 years, he said.
To Nolan, drilling the McCall Glacier - in the heart of the Arctic wilderness - seemed like a good research project.
And time is slowly running out. Like other arctic glaciers in Alaska, the 4.3-mile-long McCall is losing about 49 feet of length per year. Physical evidence shows that the glacier was probably about five miles long in the 1800s. It may disappear in about 100 years, Nolan said.
When the Brooks Range glaciers are gone, scientists may lose their best tool for looking deep into the past.
Since the late 1950s, scientists have been traveling to the remote glacier - 8,000 feet in elevation at its highest point and about 60 miles south of Kaktovik - to learn about the dynamics of the region's glacial ice and its climate. Nolan has been leading research projects on the glacier for the past six years.
In March, ANWR refuge managers granted Nolan and his research team permission to drill into the glacier for ice cores.
That's unusual for several reasons.
The glacier is part of the Arctic refuge's wilderness zone. It is almost impossible to get permission to use a mechanical tool in a federally designated wilderness. And to make things more concerning, these guys were packing fuel-powered drill rigs.
Ordinarily, that sort of work would be prohibited, said Jimmy Fox, the refuge's deputy manager, based in Fairbanks.
But Fox said the refuge staff has discretion to allow such projects. One thing they consider is whether the work can be done outside the wilderness. Another factor: Can the tools be minimized?
In this case, the only place in the refuge where it made sense to do this research was the McCall Glacier, where related work has been occurring for more than 50 years. And drilling rigs were necessary - massive ice cores can't be extracted with a hand auger, he said.
The project is also unusual because until now there haven't been many ice cores drilled out of Arctic glaciers in Alaska.
The work was challenging, Nolan said, noting that at one point, the drill hit an aquifer in the ice, filling the drill hole with water.
The team was constantly worried about losing the drill to the moving glacier, he added.
The research team pulled a 500-foot-long ice core from the glacier a few weeks ago. That's the longest ice core ever pulled out of the U.S. Arctic, Nolan said.
He said he hopes the core will provide a climatic record that goes back at least 200 years, when the Little Ice Age was cooling the northern hemisphere and arctic glaciers were still growing.
"I'd like to know how much cooler it was, and whether it was wetter or drier," Nolan said.
The ice cores were flown off the glacier in a Beaver ski plane and for now, they are being housed at the Alaska Ice Art Museum in Fairbanks.
The core samples will be analyzed by ice core researchers in Ohio and Belgium. Nolan said he hopes to have some findings by next March.