The cold truth


Over the last century, nearly all of the earth’s glaciers have shrunk, some of them dramatically. All of the glaciers in Glacier National Park, Mont., are expected to disappear in the next 15 years. New studies show that the Greenland ice sheet has lost 10 billion tons of ice per year since 2003 – 10 billion tons per year.

One professor at Iowa State has studied glaciers for more than 30 years. Neal Iverson (’83 geology), professor of geological & atmospheric sciences, is currently studying drumlins (streamlined hills that form beneath glaciers) and glacial movement. His fieldwork has taken him to the Alps, the Canadian Rockies, Sweden, Norway, and Iceland.

Iverson spent the spring semester as a Fulbright scholar in Trondheim, Norway. VISIONS spoke with him via email; the following is an edited transcript of the discussion.

VISIONS: Tell us about your current research projects.
iverson1IVERSON: We are studying the sediments that make up drumlins that have formed beneath the glacier Múlajökull in central Iceland. These drumlins are unusual because they have been shaped by a modern glacier over the last century, rather than having formed during a past ice age. We study the magnetic properties of the sediment, which tell us about the patterns of sediment movement under the glacier, and the degree of sediment compaction, which tells us about the stress at the bottom of the glacier that affected the sediment’s mobility.

We also do experiments in the laboratory that simulate the physics of glacier sliding – the process whereby glaciers slip over their beds and achieve high speeds, as high as 150 feet per day in extreme cases. The goal is to develop relationships that can be used in numerical models aimed at predicting increasing speeds of glaciers that terminate in the ocean – those rates of flow are a major factor affecting sea level rise.

What do you hope this research will tell us?
The fieldwork in Iceland is aimed at understanding how drumlins form. The work has been made possible by climate warming, which has caused the glacier to shrink and expose the drumlins for study. Results of the laboratory experiments, through their inclusion in numerical models of ice sheets, could help shed light on the extent of future glacier accelerations due to climate warming.

Why is the study of drumlins important?
Drumlins are elongate hills orientated in the direction of glacier flow. They occur in groups of as many as 10,000 individuals, hidden from view under glaciers. No one yet knows how they form, despite 150 years of study and more than 1,000 publications. Drumlins are also of interest these days because, by sticking up into the base of modern ice sheets and affecting resistance to glacier slip, they could affect how quickly parts of ice sheets move and shed ice into the oceans.

Do you include students in your research?
Many of my students have worked on glacial sediments in the Midwest because that is their interest, having grown up in the Midwest. Others have in interest in modern glacial environments, often stimulated by their love of hiking, climbing, etc. These students have worked on a glacier in northern Sweden called Storglaciären, studying its flow behavior; in tunnels beneath the Svartisen Ice Cap in Norway, studying its sliding mechanics; and most recently in Iceland studying drumlins and other landforms at Múlajökull. Students participate in all aspects of the research.

How long have you been studying glaciers?
Thirty-two years. In the spring of 1983 I graduated from Iowa State and joined a University of Minnesota field project for the summer – 80 days of camping in front of a glacier in northern Sweden, where we studied its mass balance (gain or loss of ice) and speed. I ended up doing my Ph.D. at the University of Minnesota and have been studying glaciers continuously since then.

How cold does it get where you’re working?
We work in August in Iceland, so it is not that cold. Temperatures have ranged in August from about freezing to 55 degrees F. The bigger problems are high winds (sometimes sustained winds of 60 mph) and rain, both of which are common and make working hard or sometimes impossible.

Describe your working conditions.
We camp in front of the glacier and have a cook tent that makes cooking and eating a lot easier than if we had only sleeping tents. Working consists of walking several miles each day to a particular drumlin, digging to expose fresh sediments not disturbed by slope processes, and then spending the day working in the resultant pit carefully collecting sediment samples. It is dirty work that is hard on aging knees and backs but quite enjoyable when the weather is good.

What do you wear for protection from the cold?
Most of us wear synthetic inner layers that retain most of their warmth when wet and an outer  shell that breaks the wind and is waterproof. On our feet we wear boots that are rigid to allow walking on loose stones and sufficiently waterproof to allow the many streams in the area to be crossed.

You got a B.S. at Iowa State – were you an Iowa kid? If so, how did you get interested in glaciers of all things?
I grew up in Ames until I was eight and thereafter in Sioux City, where my father worked for ISU Extension. My parents took us each year camping in the Rockies. It was seeing glaciers – and the spectacular Alpine landscapes they produce – on some of those trips, that got me interested in glaciers. Also, glaciology is rooted in basic physics (mechanics and thermodynamics), subjects that I really enjoyed as an undergraduate at ISU.

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