Charting the Ice Range
by Jenny Pitt-Clark
Battling frostbite, extreme cold and snow on the Greenland ice sheet sounds like a fast track to misery. For William Colgan, assistant professor in the Department of Earth & Space Science & Engineering at York University’s Lassonde School of Engineering, it’s all part of the experience working in some of the most forbidding places on Earth.
William Colgan is a modern-age ice man. He has spent some 300 days over the past decade traversing Greenland, the Canadian Arctic and Antarctica in a quest to better understand the interactions between glaciers and contemporary climate change. A new breed of adventure scientist, he is one of Canada’s rising stars in climate change research because of his high-tech, hybrid approach to collecting and analyzing data from ground-level expeditions and comparing it to satellite measurements on the impact of climate change.
So when the Canadian Space Agency (CSA) recently issued a call for applicants for the next round of astronauts to train for future NASA missions, Colgan was on it, hoping to add the position of astronaut to his already impressive list of credentials. Colgan’s lofty ambitions align with his love of adventure and research into ice, something that is not far off from a celestial gig to the frigid surface of Mars, a possible future destination for NASA astronauts.
Colgan, who is tall, rangy and fit (he cycles to work and was a competitive rower), has intimate experience with the physical rigour and danger associated with fieldwork in an antagonistic environment – life skills that could serve him well in space. A member of NASA’s FirnCover research team, Colgan recently returned from a 36-day expedition to Greenland to investigate how the ice sheet’s upper layer is responding to extremely warm temperatures.
Greenland is the world’s largest ice island and home to the second largest body of ice in the world, with the Antarctic ice sheet being the first. The Greenland ice sheet encompasses an area of 1,710,000 square kilometres of glaciers covered by firn, a layer of snow being slowly compacted into the density of glacier ice. Firn forms a porous, near-surface layer over the ice sheet, long thought to be a sponge soaking up glacier meltwater and keeping it from the ocean.
During the research team’s trip, the average temperatures hovered near -25 C some days. Equipped with thousands of kilograms of supplies, a radar unit and snowmobiles, the team was dropped onto the ice sheet by a Hercules aircraft.
“We travelled south to north on the ice sheet, collecting shallow core samples and deploying instrumentation to measure how firn density is changing in response to climate change,” says Colgan. “Satellite observations are being used to document how quickly the ice sheet is thinning, but in situ data is needed to understand what fraction of this thinning is due to increasing firn density over time, rather than true ice loss.”
In many ways, operating in the middle of the Greenland ice sheet is like being on your own space mission
Colgan says glaciers have become a charismatic symbol of the rapidity and magnitude of climate change. The Earth’s largest indicator of the impact of a warming world, glacier melt is increasing the mean sea level globally and decreasing water resources in many regions. The Greenland ice sheet offers a dramatic representation of the enormous effect of climate change on the Earth’s fragile environments. If the entire ice sheet melted, it is estimated that the world’s sea levels would rise by some 7.4 metres.
“Understanding glacier-climate interactions is a pressing topic,” says Colgan. “My sense is that the glaciology community feels urgency to its work, which is evident in a move away from hypothesis-based research toward objective-based research. For example, 30 years ago people were saying, ‘Why does a glacier behave that way?’ but now people are saying, ‘Tell me how that glacier will behave.’ ”
NASA’s FirnCover team is leading the way in bringing together in situ sampling and satellite observations. Colgan says the Greenland ice sheet represents probably the best opportunity to align the data collected from the surface and the satellite.
“As in many fields of the earth sciences, the vastly different spatial scales and techniques used in field versus satellite science can make it hard to bridge the gap between people comfortable deploying field instrumentation and those running big-data algorithms on higher performance computers,” explains Colgan. “On the FirnCover team, researchers do both. The same hands that deploy sensors also debug numerical code. This makes our team really aware of the strengths and weaknesses of both the in situ and satellite data.”
We worked through to the wee hours of the morning. It was -32 C that night and we were slightly short of breath at 3,200-metre elevation
This became particularly evident when data collected during previous expeditions revealed that existing climate change models used to simulate melting of the Greenland ice sheet did not accurately estimate the effect of extreme warm temperatures. In particular, the models had difficulty reproducing two six-day periods of high temperatures in July 2012, which caused dramatic melting of ice. In one instance, 28 centimetres of ice melted in one day, contributing 14 per cent of the annual melt.
The team published a study in Geophysical Research Letters in March describing how the energy associated with warmer air temperatures and increased moisture content made a larger contribution to the melting than radiant energy contributed by the sun. Existing models were not accurately simulating the effects of warm, humid air drifting on the ice sheet from southern latitudes. July 2012 offered an ominous warning of what will happen if the pace of global warming goes unchecked.
The FirnCover team, including scientists from the U.S. and Denmark, embarked on deep science expeditions onto the Greenland ice sheet in 2012, 2013 and 2015. During these expeditions, the researchers discovered that the ice sheet is losing its ability to buffer the contribution of glacier meltwater to rising sea levels. Colgan documented this observation as a co-author of a study published in the journal Nature Climate Change in January.
The extreme melting that took place in July 2012 produced a solid layer of ice that, when sampled in 2013, was found to be several metres thick. The ice effectively formed a hard lid on top of the firn cover and reduced its permeability to meltwater, which in turn caused the meltwater to drain off into the ocean. The researchers are continuing to pursue this surprising revelation by examining an expanded area of the ice sheet to determine further changes.
Science aside, research in space holds many similarities to what Colgan experiences in Greenland. Exploring the ice sheet is fraught with danger posed by crevasses in the glaciers, sudden storms and bone-chilling cold. During storm periods, the research team was tent-bound for up to three days, limiting their ability to collect data and emphasizing the urgency to work at maximum capacity before such interruptions occur.
“Responding to weather challenges can require some serious flexibility,” says Colgan. “One evening at Summit Station during FirnCover 2016, we received notice at 2200 hours advising that our plane was being recalled back to the coast at 0800 to escape an approaching storm. (There is no hanger at Summit, so aircraft can be rather exposed just sitting on the ice sheet.) We still had some work to do, so we worked through to the wee hours of the morning. It was -32 C that night and we were slightly short of breath at 3,200-metre elevation, but the FirnCover team appreciated that collecting the data was paramount.”
Mars is the fourth planet from the Sun and Earth’s closest neighbour, and a much icier and more barren version of Greenland. Daytime temperatures reach a balmy -65 C, while the evenings approach -120 C. The search for water, or rather ice, is a big part of current satellite measurements and rover expeditions on the surface of Mars.
“In many ways, operating in the middle of the Greenland ice sheet is like being on your own space mission,” says Colgan. “It is just you and your six colleagues responding to directions and asking for help over the satellite phone. You get to wear these big, bulky suits, live in hostile conditions, while at the same time trying to deploy really sensitive instruments and do science. It just takes so much effort to keep yourself fed and warm.”
On his chances of making it into the next round of the astronaut selection process, Colgan says, “There’s probably a one in 1,000 success rate,” noting that he regards it as strictly a side project. He is pragmatic about his chances and about the potential for travel into space, but the application has offered him an opportunity to dream.