ORONO, Maine — Atop a glacier inside the crater of an active Chilean volcano, a group from the University of Maine’s Climate Change Institute recently drilled deep into the ice to open a window to the past and, they hope, the future.

The UMaine team returned in late February from a joint expedition to the Andes Mountains with the Climate Change Institute and the Centro de Estudios Cientificos from Valdivia, Chile.

Led by the institute’s director, Paul Mayewski, UMaine climate scientists Bjorn Grigholm, Mariusz Potocki, Daniel Dixon and Andrei Kurbatov were joined by a contingent of Chilean scientists and arrieros (the Chilean equivalent of cowboys), as well as a Californian scientist and an expert in ice core drilling.

The group was flanked by 20 pack mules, six horses and, for parts of the journey, domestic dogs during the trip to the snowy 19,000-foot summit.

Past eruptions have left behind craters, some of which are now home to glaciers that are vital to surrounding South American cities.

“This area is really important because the glaciers are one of the primary water sources for Santiago, which is the largest city in Chile, and it’s still growing,” Mayewski said Tuesday.

The melting provides Chile with drinking water and hydroelectric power, but Chile is concerned about the future of its lifeblood, according to Mayewski.

Many of the mountain glaciers are shrinking. Chilean researchers have watched the ice recede since the 1970s and are worried about the water supply, which is Santiago’s main source of drinking water during the dry season.

While studying the receding glaciers, researchers will use the ice core they drilled recently to test and glean information about changes in the climate and atmosphere, which Mayewski said have likely contributed to the loss of glacier mass.

The 190-foot ice core taken from the glacier has been cut into 70-centimeter sections, according to Mayewski. Two-thirds of the core are on their way to UMaine for testing; the rest of the sections were given to Chilean scientists and a lab in Washington state for other research.

The sections are still in a shipping container, along with much of the expedition’s gear, heading to the United States, Mayewski said. Once the ice reaches the labs, the institute will run tests to see how conditions in the area and across the globe are affecting the climate and air quality in the Andes region.

For example, researchers are looking to see how an uptick in copper mining operations in the region might be affecting air quality.

Ice cores are a dependable indicator of past climate conditions and air quality, giving researchers a year-by-year picture of what the world was like in the past and how it could be in the future.

Samples from around the world can even reveal a picture of how changes humans have made in just the past few decades have affected contaminants in the globe’s atmosphere, according to Kurbatov.

“Ice cores, if you’re looking back, had a much higher level of lead 20 years ago than today because people took action,” Kurbatov said, arguing that lead contamination decreased soon after use of the poisonous metal became more regulated.

This research trip to Chile came after three years of visits Mayewski and others made to the site to conduct reconnaissance and plan for the expedition.

“It can be extremely exhausting, and we have to take our time initially getting to the site,” Grigholm said of three-week climb to the 19,000-foot altitude.

For every few thousand feet the group climbed, it had to stop to set up camp for a few days to get acclimated to the new altitude and environment.

Past trips have sent researchers from the institute to Asia, Greenland, Russia, New Zealand and, most frequently, Antarctica.

“Most of our funding usually comes from places like the National Science Foundation, NOAA and NASA,” Mayewski said, “but the majority of this funding actually comes from a private donation from the Garrand family in Portland.”

Mayewski said ice core research is vital to predicting what effect global climate change will have around the globe.

“At the rate we’re going, by the year 2100, Antarctica will be about 3 degrees centigrade warmer than it is today.” Mayewski said. “The last time Antarctica was that warm was about 20 million years ago, when Antarctica didn’t have any ice on it.”

For more information about ice core research, visit http://climatechange.umaine.edu/icecores/IceCore/Home.html.

To read more about the glacier expedition, visit the Climate Change Institute’s blog at http://umaine.edu/news/blog/category/climate-change/.