Next year, a data collection site on the Wolverine Glacier in southern Alaska in the United States will disappear due to melting. The site, near the terminus—aka the lower end of the glacier—contains a mass balance stake that Christopher McNeil, a geophysicist for the US Geological Survey, uses to measure the rate at which the glacier is growing or melting. “We’ve actually had to deal with this at pretty much all of our glacier sites,” McNeil says.
Snow and ice are extremely important tools for researching our environment. There are ice cores from the poles and from glaciers around the world stored at the National Science Foundation Ice Core Facility in Denver; they show everything from when volcanic events happened to how much carbon dioxide and methane were in the atmosphere millions of years ago. Other researchers use snow to understand the amount of toxins or pollution in our environment today.
“Snow is a really great medium to work in because you get the snow layers,” says Aleksandra Karapetrova, a graduate student in the environmental toxicology program at the University of California, Riverside. Her work focuses on measuring the amount of microplastics that are falling from the atmosphere. Snow falls during storms, so if you know the history of the weather, you can use snow as a physical record of what’s been in the air.
“I can basically time-stamp my samples based on where in the snowpack I’m sampling from, because I know when the storm happened,” Karapetrova says. Snow also doesn’t contain organic matter that can make identifying materials of interest difficult. But with snowfall decreasing and glaciers melting because of climate change , researchers are finding it harder to access their favorite research tools.
They are having to adjust protocols, safety measures, and scientific models to combat the changing conditions. Data is harder to harvest, while at the same time being less consistent, making it even more difficult to study and understand the world as it changes. A decade ago, scientists taking measurements on glaciers needed only basic mountaineering skills, like skiing and using crampons.
But as warming temperatures have made crevasses wider and snow bridges thinner, a lot more technical mountaineering education and experience is now needed. “It absolutely just makes getting around on the glacier not only more challenging, but in some aspects more hazardous,” McNeil says. His team spends a lot more time on the glacier “roped up”—where each team member is tied to the others, so if one person falls through a thin patch of ice, the others can stop their fall.
This makes moving on the glacier much slower. And when a snow bridge over a crevasse becomes so thin that it’s impassable, then finding another route to reach a data collection site can take even more time. Such sites are located all over glaciers and are often marked with a mass balance stake.
These metal stakes—usually tick marked with measurement lines—are inserted at known depths on the glacier. They’re then visited multiple times a year to measure how much ice has accumulated or been lost at these points. But as snow and ice melt, reaching some stakes can become impossible.
“There have been lots of times we walked to a stake, and you could see it, but there’s a moat of crevasses that are 10 to 20 feet wide,” says Ben Pelto, a postdoctoral research fellow at the University of British Columbia. “And it’s like, well, there’s no way we can get over to that stake anymore. It impacts the amount of research you could do and the safety with which you could do it.
” The danger has also been heightened for researchers working just above the snowline on mountains. For Karapetrova, the massive swings in temperatures can cause rock falls or avalanches, making it hazardous for her to move on the mountains near June Lake in California where she collects her snow samples. Every researcher mentioned having to move their sampling seasons earlier or having to work faster in fewer months because of the longer and warmer summers.
Karapetrova has been limited to collecting samples in June and July, when previously scientists could collect all the way into August. Jason Geck, an associate professor at Alaska Pacific University who specializes in glaciology, has been bringing students on an annual research trip in May to collect samples on the Eklutna Glacier near Anchorage for over a decade—but he’s had to shift it to April because melting is happening earlier. “It’s great to have a few students out for two or three weeks on the glacier to get the hands-on field experience,” he says.
“Now it’s being condensed down into a day. From an educational perspective, the students are suffering. ” Geck has also resorted to using helicopters to travel, instead of hiking or skiing, for efficiency and safety—which, of course, contributes even more to climate change.
As the safety and accessibility of high mountain snow and glacier ice decreases, the biggest loss is data consistency. Even just shifting data collection sites by a few hundred meters or from one side of a glacier to another can introduce discrepancies. Some areas of a glacier are more shaded, steeper, or windier, changing the rate at which snow accumulates and ice melts.
And the data losses are getting larger. A weather station on Gulkana Glacier in the eastern Alaska Range, which has been collecting weather data since the 1960s, will be decommissioned in the next three years. As the glacier has receded, it’s left behind pockets of ice that rocks can slide off of that make accessing the station too problematic and dangerous, ending a consistent weather record that stretches back over half a century.
There’s a new weather station a few miles up the glacier that will replace it, but it will never be exactly the same. “Any long-term series data is very valuable,” says Geck. His biggest fear is arriving at a mass balance stake to see it lying on its side because the snow has melted too much to keep it upright.
“It’s not a fun thing to show up and see your pole on the ground,” he says. Geck estimates that every time a pole falls over, it’s about $1,000 worth of labor, equipment, and knowledge lost. He has started placing time-lapse cameras to record the stakes, so if they do fall, he knows when and is still able to extract some information.
But at least Geck has a way of somewhat future-proofing his data collection. Karapetrova reckons that her current sampling might not even be possible in the future. Her strongest data comes from fresh, dry snow after a storm.
So as low-snow years become more and more common, she has fewer chances to collect samples. This last season had the second-longest period of days without snow during the winter at her June Lake location, pushing 70 days. So for more than two months, Karapetrova couldn’t get any measurements of the microplastics in the atmosphere from the snow record.
Working around these data inconsistencies then makes conveying the reality of climate change more difficult. Consistent data is needed to tell a powerful scientific story, and constantly having to change collection sites means recalibrating the record, making it harder to draw strong conclusions, according to McNeil. Every research breakthrough has to come with more qualifiers and explainers.
“It just makes your life more difficult,” Pelto says. “And it makes your data a little less quality. ” Inconsistent data and interrupting long-term data sets isn’t a trivial loss.
Models that scientists create to understand what is happening across an entire system and what the future holds for it—whether that’s a glacier, mountain, snowpack, or the atmosphere—are actively becoming outdated because of the shifting climate and resulting data loss. On the glaciers, Pelto and his team now need to do aerial surveys every few years to correct their on-field ice measurements. Their data collection happens on the safe, flat parts of the glacier that they can access.
But most of the glacier is covered in crevasses, with many more now exposed due to rising amounts of snowmelt, which then increases the glacier’s surface area, leading to more melting in these parts when compared to the flat areas the scientists take samples on. The models Pelto uses thus need to be updated with the aerial data to keep them accurate. “This always would have been a bias,” he says.
“But it’s becoming a larger bias. We’re being forced to measure places where the glacier is safe to travel on, which also often happens to be places where the glaciers are doing a little better. ” For Karapetrova, the models she uses aren’t calibrated for the severe droughts and inconsistent weather now seen in the mountains.
“The models have to somehow take into account this ever-changing climate,” she says. “It complicates the story that you’re trying to tell, and makes the predicting-the-future part harder. ”.
From: wired
URL: https://www.wired.com/story/glacier-melting-climate-research/
