Snowflakes, ice and glaciers

May 04, 2006, volume 36, no. 1
By Michael Boxall



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There's been a lot of news recently about glaciers melting as the planet warms. But not all glaciers act in the same way. Why do some move faster than others in their inexorable slide toward the sea, while others don't seem to move at all?

For contributions to our understanding of these processes, earth sciences professor Gwenn Flowers has won one of three Outstanding Young Scientist awards presented annually by the European Geosciences Union. Flowers is also a Canada Research Chair in glaciology.

 The award confirms that a “leap into the dark” she made when she chose to take a graduate degree in glaciology was a good choice. Her undergraduate degree had been in physics, a subject she liked in high school because of its explanation of why the everyday world works the way it does. Studying at the University of Colorado, she wrote her bachelor's thesis under the direction of Nobel laureate Carl Wieman.

“That was a really exciting project, related to the work he won the Nobel prize for,” Flowers says. Yet it also taught her that she didn't really have the temperament for experimental physics.

“It was an optics project, in an acoustically isolated lab. We were using lasers, so it was dark all the time. I'd taken a course in glaciology because I grew up in Colorado and I always liked being outside. It was surprisingly hard. And that intrigued me. I thought, ‘This is real science. It's physics-based and it's chemistry-based and it's mathematical. But it's all about snowflakes and ice.'  ”

Although she had not actually seen a glacier, she picked glaciology for her graduate studies and moved to Vancouver. After five years at UBC she wrote a doctoral thesis entitled, A Multi-Component-Coupled Model of Glacial Hydrology. The emphasis was on numerical modelling, using data she had collected in the Yukon to analyse mathematically the nature of the glacier drainage system from the surface to the glacier bed.

“Glaciologists are interested in why glaciers move the way they do. And water in and under the glacier has a lot to do with glacial dynamics - how fast the ice flows, the seasonality of the flow regime, how the water flow changes from year to year. So if we can understand basically how the plumbing system of the glacier works we have a better chance of understanding the dynamics.”

Glaciers form the largest reservoir of fresh water on the planet. Essentially frozen rivers, they are pulled by gravity toward the sea. Their speed depends on a number of interconnected factors. Friction at the bottom caused by rock and debris provides resistance to the gravitational forces pulling the glacier downhill. The plumbing is the various pipes and channels by which water finds its way to the bottom of the ice and acts as a lubricant.

“The advantage of using numerical models as well as doing fieldwork is that you can extend the study spatially,” she says. “You can get information from models about maybe the whole area of the glacier, not just the points that you measure. And at the very best you can make predictions into the future.”

Flowers says one of the most interesting questions relating to global warming and glaciers is the possibility of thresholds, sudden dramatic changes from one state to another. She cites the example of the Greenland ice sheet, where there has been a recent and dramatic acceleration of several large outlet glaciers. This speed-up may be due in part to increased access of meltwater to the bed, causing a disproportionately large response to a small perturbation - a small cause having an unexpectedly big effect.

She lists two goals for the rest of her career: to help governments form climate policy, and to train “a small fleet of really qualified good people and good scientists.”

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