U of L geographers observe climate-related tipping point to accelerated permafrost thaw

caroline.zentner — Mon, 16 Jan 2017 18:22:05 +0000

Research by Drs. Laura Chasmer and Chris Hopkinson, ��Ѹ��Դ��߿�Ƭ of Lethbridge geography professors, indicates that the 1997–1998 El Niño may have served as a tipping point for accelerating permafrost loss in their study area in the Northwest Territories.

The study, Threshold loss of discontinuous permafrost and landscape evolution, has been published in the latest issue of the prestigious journal Global Change Biology.

“What we’re seeing is that the permafrost thaw has accelerated since the severe El Niño that we had in 1998. Between 1970 and 1998, the area of permafrost in our study site shrunk by roughly four per cent. Between 1998 and 2015, it shrunk by an additional 13 per cent,” says Chasmer. “The research shows that unusually warm air temperatures, a shortened snow-cover period and the timing of snowfall may have shifted the watershed into a new state. This could have significant effects on greenhouse gas fluxes, water resources, wildfire and food security.”

“The extra energy during and following El Niño shifted the state of the system into an entirely new condition and created this accelerated rate of change,” says Hopkinson. “What we don’t know is whether the watershed system has readjusted to a new kind of steady state or whether it’s going to continue that rapid acceleration of loss.”

Chasmer and Hopkinson surveyed the Scotty Creek watershed, about 50 kilometres south of Fort Simpson in the Northwest Territories, using airborne Light Detection and Ranging (LiDAR). They conducted surveys in 2008, 2011, 2015 and 2016. Their data, combined with increased runoff from this watershed and others nearby, indicate that similar patterns of permafrost loss may be occurring across the region. Within their study area, the snow-covered season is 35 days shorter than it was in the 1970s.

Permafrost, made up of layers of old moss and soil that remain continuously frozen for two years or more, contains a large store of carbon. When it starts to thaw, significant amounts of carbon and methane are released into the atmosphere. In addition, thawing permafrost saturates the ground, causing trees and infrastructure like houses to tip over and slump, and creates difficult terrain for animals and traditional hunters to traverse. Chasmer and Hopkinson also suspect the increase in shrubbery they’ve found is because water runoff from thawing plateaus gathers into small channels and streams, which could dry out some of the wetland areas.

“That has potentially big implications for forest fires,” she says. “If wetlands dry out they become a fuel source, which could be why much larger areas of northern ecosystems are starting to burn.”

“If this rate of loss continues, total permafrost loss within our study area could occur by around 2044,” says Hopkinson. “We need to continue monitoring this area by doing LiDAR surveys every few years to determine if the system is in a new steady state or if it’s continuing to decline.”

An illustration of the changes seen in the study area can be found on YouTube.

Hopkinson continues to explore at the U of L

caroline.zentner — Tue, 10 Nov 2015 22:24:56 +0000

A ��Ѹ��Դ��߿�Ƭ of Lethbridge professor named one of Canada’s greatest explorers has traded his high-flying days for the chance to mentor the next generation of discoverers.

When Canadian Geographic magazine published its list of Canada’s greatest explorers 2015, Dr. Chris Hopkinson, a U of L geography professor, found his name in the ‘H’ section, right along with astronaut Chris Hadfield.

“I was surprised and humbled. I thought ‘you’ve got to be kidding me; I can’t be listed next to this guy. He legitimately is in that category,’” he says.

Hopkinson was a student at England’s ��Ѹ��Դ��߿�Ƭ of Manchester when he heard about an opportunity to investigate glacial water resources in the Alberta Rockies. He’d been clambering around the Swiss Alps for four summers doing glaciological work as an undergraduate student and was ready for another adventure. He signed up for graduate studies at Wilfrid Laurier ��Ѹ��Դ��߿�Ƭ and arrived in Alberta in 1995.

“When I first came here we didn’t have lasers and had to work with aerial photogrammetry,” he says.

Hopkinson has been involved in the remote sensing field during a time of rapid development as LiDAR (light detection and ranging) sensors became more widely available. He went from lugging survey equipment over the Wapta Icefields to flying over them in a LiDAR-equipped plane. LiDAR, which emits laser light pulses, is used to quickly collect highly accurate elevation data that creates a three-dimensional map of the Earth’s surface.

His work, both as a grad student and following his doctoral degree, allowed him the opportunity to use state-of-the-art remote sensing equipment and fly over a big swath of Canada, South America and Australia. In addition, he and several colleagues started a consortium that brokered LiDAR data services to research partners around the world.

“We helped grow the LiDAR research community in Canada,” he says.

After spending a year as an environmental research scientist at the Commonwealth Scientific and Industrial Research Organisation in Australia, Hopkinson joined the U of L in 2013. He and his students are now conducting research in several areas and, in addition, Hopkinson has an ambitious goal on his mind.

“What we’re hoping to do is somehow cobble together a couple of million dollars to buy a system and build some capacity here at the ��Ѹ��Դ��߿�Ƭ where we could be the centre of excellence for this activity in Canada,” he says. “We want to develop algorithms, software and applications but it’s hard to do that if the only way to get the data is to buy it on a commercial basis. And you can’t really train students if you don’t have access to the technology.”

His students’ research interests are broad. One project involves developing hardware for in-situ sensors to measure hydrometeorological variables such as snow depth and water levels. The three students collaborating on the project, Zhouxin Xi, Reed Parsons and Sean Herridge-Berry, eventually hope to commercialize their work.

Josh Montgomery, David McCaffrey and Husam Ali are working on a project to develop a water-monitoring portal in conjunction with the Canada Centre for Remote Sensing and the Alberta government.

Another student is studying periglacial environments — the landscape surrounding glaciers — using thermal and laser imaging to gauge rates of change.

“What we’re seeing is that there is quite a significant storage of water as buried ice in these periglacial environments so we’re trying to get a better handle on how much this is contributing to the water resource and if it’s becoming more important through time,” he says.

Using survey equipment, Dr. Chris Hopkinson, right, and his students, Zhouxin Xi, far left, David McCaffrey, centre, and Josh Montgomery do base support for an airborne mission at Castle Mountain.

A further project involves installing a telemetered weather station array on the ski hill at Castle Mountain. Castle Mountain Resort and Tough Country Communications are providing in-kind support for the research. The weather stations provide data on precipitation, snow depth, wind speed, wind direction and more. The data will support other studies, such as McCaffrey’s investigation of whether tree lines are advancing in the area or Mark Derksen’s internship project to optimize LiDAR-based snow mapping in mountainous headwaters.

Dr. Craig Mahoney, a post-doctoral fellow, is also working with the Canadian Forest Service on a forest-mapping project in the Northwest Territories. Using airborne and satellite LiDAR, he’ll be mapping forest heights, biomass and forest canopy closure.

For another project, Hopkinson, Montgomery and Dr. Laura Chasmer (Alberta Innovates Technology Futures intern, post-doctoral fellow and Hopkinson’s wife) are working on a wetland classification project in Alberta. The data will give the province an inventory of its wetland areas, including marshes, fens, bogs, ponds, lakes and swamps.

“These students and research fellows are doing cutting-edge work in remote sensing and it would be great if we could keep them here in Alberta by offering long-term employment through a centre of excellence,” says Hopkinson.

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U of L geographers observe climate-related tipping point to accelerated permafrost thaw

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Hopkinson continues to explore at the U of L

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