Melting ice on the Greenland ice sheet could eventually expose an abandoned U.S. military base that contains hazardous waste, scientists warn.

Camp Century was built in 1959 to look into the possibility of deploying nuclear weapons from the Arctic during the Cold War. The base was closed in 1967, with the notion that any hazardous material left there would be encased in ice forever. However, new research suggests the base could be exposed to the environment as early as 2090.

It is believed the base may contain biological, chemical and radioactive waste in quantities sufficient to "disrupt nearby ecosystems," the study warns.

"Two generations ago, people were interring waste in different areas of the world, and now climate change is modifying those sites," said William Colgan, a climate and glacier scientist at York University in Canada and lead author of the study. "It's a new breed of climate change challenge we have to think about."

Camp Century covers 55 hectares, "roughly the size of 100 football fields," about 200 kilometers from Greenland's coast. When it was operating as a U.S. base, up to 200 soldiers lived in "the city under the ice," as the camp was sometimes called.

Researchers inventoried the waste at the base, "ran climate model simulations" and consulted old engineering records to determine how deep the waste is buried and how much the ice has moved since the 1960s.

The hazardous substances include 200,000 liters of diesel fuel, 240,000 liters of wastewater, polychlorinated biphenyls, or PCBs, and "unknown volume of low-level radioactive coolant from the nuclear generator."

All of that could enter the environment as the climate warms and the ice sheet melts, researchers said.