Melting ice exposes frozen past

Glaciers in Tracy Arm, Alaska. File photo / Supplied.

Melting ice sheets and glaciers are exposing ancient artefacts that had been covered with thick layers of ice for millennia.

The discoveries are providing new insights into the behaviour of our ancestors - but they come at a price.

So rapid is the rise in global temperatures, and so great is the rate of disintegration of the world's glaciers, that archaeologists risk losing precious relics freed from the icy tombs.

Wood rots in a few years once freed from ice, while rarer feathers used on arrows, wool or leather crumble to dust in days unless stored in a freezer.

As a result, archaeologists are racing against time to find and save these newly exposed wonders.

At Juvfonna in Norway, reindeer hunting gear used by the Vikings' ancestors has been found littering the ground as the front edge of Juvfonna's ice sheet has retreated.

A section almost 20m wide has disappeared over the course of a year, exposing several hundred artefacts. "It's like a time machine ... the ice has not been this small for many, many centuries," says Lars Piloe, the Dane heading a team of "snow patch archaeologists".

Bows and arrows, specialised hunting sticks and even a 3400-year-old leather shoe have been found at the site in the Jotunheimen mountains, home of the "ice giants" of Norse mythology.

"Our main focus is the rescue part," he says. "There are many ice patches. We can only cover a few. We know we are losing artefacts everywhere."

Similar discoveries have been made in glaciers or in permafrost from Alaska to Siberia.

Patrick Hunt, of Stanford University in California, says there is an alarming rate of thaw in the Alps: "This is the first summer since 1994 when we began our field excavations above 2500m that we have not been inundated by even one day of rain, sleet and snow flurries.

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