Global warming is causing an Alaskan glacier to melt at the fastest pace in 400 years

Doyle Rice | USA TODAY

Show Caption Hide Caption New study finds glacier in Alaska melting at unprecedented rate A team of researchers spent a month on the summit of Mt. Hunter collecting ice cores. Their goal was to study how the climate of the Alaska Range has changed over the past 400 years.

One of the USA's tallest glaciers is melting at the fastest pace in 400 years, a new study reports.

The study said melting on Mount Hunter in Alaska’s Denali National Park can be linked mainly to rising summer temperatures in the region.

"We have not seen snow melt like this in at least four centuries,” said study lead author Dominic Winski, a glaciologist at Dartmouth College.

New ice cores taken from the top of Mt. Hunter show summers there now are least 2 to 3 degrees Fahrenheit warmer than they were during the 18th, 19th and early 20th centuries. Specifically, the ice core record shows 60 times more snow melt occurs today than did 150 years ago.

Ice cores are good records of past climate because the water, snow and air in the ice contain evidence of atmospheric conditions over hundreds to thousands of years, the Byrd Polar Research Center said. The seasonal snowfall and its gradual change to ice provide an annual record of snowfall amounts and atmospheric conditions throughout the year.

In this research, the scientists drilled two ice cores that gave a record of the climate there going back to the mid-17th century.

The warming in Alaska coincides with warming in the tropical Pacific Ocean, according to the study. Other studies have shown the tropical Pacific has warmed over the past century due to increased greenhouse gas emissions from the burning of fossil fuels such as oil, coal and gas.

"We suggest that warming of the tropical Pacific Ocean has contributed to the rapid warming on Mt. Hunter by enhancing high‐pressure systems over Alaska," the study authors said. High pressure systems in the summer usually bring sunny skies and warmer temperatures.

Understanding how mountain glaciers are responding to climate change is important because they provide fresh water to many heavily populated areas of the globe and can also contribute to sea-level rise, Winski said.

Luke Trusel, a glaciologist at Rowan University who was not part of the study said “this adds to the growing body of research showing that changes in the tropical Pacific can manifest in changes across the globe. It’s adding to the growing picture that what we’re seeing today is unusual."

Overall, Alaska is seeing much warmer weather than in the past: The state has seen a growing trend of milder temperatures overall through the past few decades, weather.com meteorologist Chris Dolce said earlier this year. NOAA said four of the past eight years rank among the top four warmest years on record in the state.

Deke Arndt, the head of NOAA’s Climate Monitoring Branch, said that "in the context of a changing climate, the Arctic is changing more rapidly than the rest of the planet."

The study appeared in the Journal of Geophysical Research: Atmospheres, a publication of the American Geophysical Union.