New ice cores suggest Alps have been strongly warming since 1980s

Ohio State University: Less than 20 miles from the site where melting ice exposed the 5,000-year-old body of Ötzi the Iceman, scientists have discovered new and compelling evidence that the Italian Alps are warming at an unprecedented rate.

Part of that evidence comes in the form of a single dried-out leaf from a larch tree that grew thousands of years ago. A six-nation team of glaciologists led by The Ohio State University drilled a set of ice cores from atop Mt. Ortles in northern Italy, and described their early findings on Monday, Dec. 9 at the American Geophysical Union meeting in San Francisco.

The Alto dell’Ortles glacier, which did not show signs of melting for thousands of years, now appears to be shifting away from a constantly below-freezing state to one where its upper layers are at the melting point throughout the year, said project leader Paolo Gabrielli, research scientist at Byrd Polar Research Center at Ohio State.

“Our first results indicate that the current atmospheric warming at high elevation in the Alps is outside the normal cold range held for millennia,” he said. “This is consistent with the rapid, ongoing shrinking of glaciers at high elevation in this area.”

As they drilled into the glacier in 2011, Gabrielli and his team discovered that the first 100 feet (about 30 meters) of the glacier was composed of “firn”—grainy, compacted snow that had partly melted. Below that, they found nothing but solid and colder ice all the way down to the frozen bedrock.

That suggests that snow was accumulating on the mountaintop and was compacted into ice for thousands of years without ever melting—until about 30 years ago, which is when each year’s new deposit of snow began melting...

Mt. Ortles in the Italian Alps, shot by Roberto Ferrari, Wikimedia Commons via Flickr, under the Creative Commons Attribution-Share Alike 2.0 Generic license