An Icelandic researcher has released his findings about the oldest known polar bear remains on Earth, which suggest the northern bears may have adapted to warmer climates and limited sea ice in the past.

Geologist Olafur Ingolfsson of the University of Iceland discovered the well-preserved lower left jawbone of an adult polar bear while training graduate students on the field in Svalbard, Norway.

"We were actually doing training, mapping the sediments for training purposes when we discovered the jawbone. So it came as a little bit of a surprise," Ingolfsson told CBC News in an interview that aired Wednesday.

An article co-authored by Ingolfsson about his fossil find is posted on the website of the journal Polar Research.

Ingolfsson estimated that the fossil is 110,000 to 130,000 years old, based on analysis of the fossil and the sediment on it. Previously, the oldest polar bear fossils were around 70,000 years old.

Given the estimated age of the jawbone, and taking into account molecular biologists' claims that polar bears have been around for more than 200,000 years, Ingolfsson said ancient polar bears must have lived through at least two ancient periods in which the Arctic was not as cold as it is today.

"We know that there have been periods for the past couple of hundred thousand of years which have been warmer and with less sea ice than today," he said.

That possibility may challenge scientific concerns about the future of polar bear populations, as climate change melts the Arctic sea ice that is the bear's habitat and threatens the species' survival.

But both Ingolfsson and Ruth Klinkhammer, a spokeswoman for the Arctic Institute of North America at the University of Calgary, said the ancient jawbone cannot predict exactly what will happen to polar bears today and in the future.

"Regardless of what happened in the past, we still have to look at what's happening now," Klinkhammer said.

Ingolfsson said his research on the ancient polar bear bone will continue, with DNA extraction expected to happen next.