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Climate change is doing weird things to the snow in Alaska

There are places where climate change actually means more snow

by Alex Lubben
Dec 20 2017, 10:03pm

On one of the warmest days on record in Alaska, a group of climate researchers took a helicopter ride up to 13,000 feet above sea level, hiked up a mountain, and helicoptered to a glacier on Mount Hunter — all to collect data for a groundbreaking new study on the regional snowfall near North America’s tallest peaks.

But first, to get to their research site, the researchers from Dartmouth College, the University of Maine at Orono and the University of New Hampshire, had to land a plane on a glacier, where they set up camp. Next, in order to acclimatize themselves to the thin, mountain air, they had to hike halfway up Mount Denali, the highest peak in North America. Then they hopped in a helicopter and flew to the glacier, where they drilled 700 feet below the surface ice to collect ice cores — essentially long, slim tubes of ice — that hold the key to historical climate data.

The cores told the story of the regional climate going back 1,200 years and revealed a surprising outcome of global warming. The findings, published Tuesday in the journal Scientific Reports, posit that climate change has actually led to double the amount of snowfall in the region because warmer air tends to be more conducive to moisture — hence the snow.

Credit: Brad Markle

As climate change takes its course, hurricanes are become more intense, and storms in certain parts of the world are increasing in frequency and intensity. That’s what’s happening in Alaska, says Erich Osterberg, an assistant professor of earth sciences at Dartmouth College and a lead researcher on the study, told VICE News.

“This is really a story about increased winter storms in Alaska, and the effect on those increased winter storms on snowfall in this area,” he said. “That’s why I really see the parallels [between our research and] the intense hurricane season and the increase in storms on the East Coast.”

But warmer air alone can’t account for the remarkable increase in snowfall since 1840 that the researchers observed — the annual rate has more than doubled in the 150-year period.

Meanwhile, the snowfall in much of Alaska has actually been way below average, leading the organizers of Alaska’s famous Iditarod dogsled race to cart in snow for the ceremonial start of the event in Anchorage. Precipitation is increasing across Alaska, but where the researchers were, it’s so cold that all precipitation is snow. That’s not the case in, say, Anchorage, where in the summer it’s warm enough to rain.

And there’s a lot more precipitation than there used to be. “We haven’t seen this amount of precipitation in over 1,200 years,” Osterberg told VICE News. “We expected to see a small increase, because that’s what the instrumental records show, the weather stations show, but to see a doubling in the amount of snow was unexpected and remarkable.”

Credit: Erich Osterberg

Though recent changes in snowfall in the region are well-documented, this study is the first to show that the most dramatic changes in the last millennium began occurring after humans started pumping greenhouse gases into the atmosphere in the mid-nineteenth century.

In the last few decades, the average snowfall in the area has been about 18 feet. Before humans started pumping greenhouse gases into the air, annual snowfall was closer to eight or nine feet, according to Winski.

To account for the huge increase in snowfall, the researchers needed zoom out and look to climate models, too. They found that, combined with warmer, more moisture-rich air, warming waters in the western Indian and Pacific oceans created a low pressure system in the Gulf of Alaska that drove snowy weather to the region in Alaska.

This study is the latest in a series of studies that have focused on the sometimes counterintuitive effects that global warming will have on our changing climate. In November, a group of researchers at NASA found that melting sea ice could actually cause sea levels to drop in certain places, even if they contribute to overall sea level rise globally.

“One of the reasons that getting these records is so important is that climate change will affect different parts of the world differently,” lead researcher Dominic Winski of Dartmouth College told VICE News. “If we’re going to prepare for the future, knowing how climate change will affect specific regions of the world is extremely important.”