I can still remember the first time that I discovered that glaciers could flow fast, similar to a raging river. I had always thought of glaciers as these stagnant, large bodies of ice. If they moved, it had to be at a glacial pace of only a few inches per year. However, there are regions of the Greenland Ice Sheet that flow up to 100 feet per day! My research focuses on these fast-flowing regions.
About half of the Greenland Ice Sheet drains into fast-flowing outlet glaciers. These glaciers terminate in the ocean, where chunks of ice break off as icebergs. As you might expect, the ice that is contact with the ocean is sensitive to changes in the ocean temperature. Over the last decade, the ocean waters near Greenland have warmed, and consequently, the ice in contact with the ocean has melted more than usual. As a result, many of the outlet glaciers have retreated and accelerated. However, it’s not a simple 1-to-1 relationship: more ocean warming does not necessarily lead to faster glacier retreat, and that is where my research comes in. I’m interested in understanding the additional parameters that influence the glacier response to climate change. Which parameters are the most important for predicting future glacier loss and consequently future sea level rise? For example, the depth of the fjord floor can greatly influence the glacier’s response to a small change in its terminus position. If the glacier retreats into deeper water, then less of the glacier front is in contact with the fjord walls and floor. As the fjord walls and floor provide resistance to flow through friction, the reduction of this contact causes the glacier to flow faster and therefore decrease. This mechanism occurs until the glacier retreats into shallower water, where a larger portion of its front is in contact with the fjord walls and floor.
Although I have been studying glaciers for over six years now, I’m always amazed at how quickly glaciers can change and how differently they can behave. It definitely keeps things exciting!
- Laura, University of Washington, USA