Wyoming Scientist Investigates Greenland's Melting Ice

Nov 6, 2015

Russell Glacier, Greenland
Credit Photo by Henry Patton, Flickr Creative Commons

If the entire Greenland ice cap were to melt, scientists predict sea levels would rise more than 20 feet. Climate change is speeding up melting of the ice sheet, but it’s not clear by how much. The New York Times recently profiled one of the few research projects taking direct measurements to answer that question. One of the researchers is University of Wyoming graduate student Brandon Overstreet. He’s a doctoral candidate in hydrology. Overstreet told Wyoming Public Radio’s Stephanie Joyce that the purpose of the research is to figure out how much meltwater from the surface of the ice sheet is actually making its way to the ocean.

STEPHANIE JOYCE: What does it look like there?

BRANDON OVERSTREET: On the surface of the ice sheet is this really complex network of streams and lakes that form each summer during the melt season. And the rivers will flow onto the surface of the ice and then terminate in these moulins which are just these vertical waterfalls into the ice sheet. So, instead of just being this featureless landscape, in fact the surface of the Greenland ice sheet is very dynamic and pretty spectacular. The rivers are just this brilliant color of blue, and the lakes even look almost tropical, but you’re surrounded by ice.

JOYCE: I would imagine slightly less pleasant to jump into.

OVERSTREET: It’s not recommended. And in fact my job centered around keeping people out of the water.

JOYCE: The New York Times story opens with a pretty dramatic scene of you clipping in your climbing harness to an ice anchor and then dangling over the edge of one of these streams, which as I think the article put it, if you fell in, would result in a 100 percent fatality rate. Why were you doing that?

OVERSTREET: So what we were doing was measuring discharge on the river and in order to do that we needed to deploy an instrument on the water. It was essentially a boogie board with what’s called an acoustic doppler current profiler that sends pings into the water and based on the reflection of those pings can tell us how deep the water is as well as how fast the water is moving. But in order to get those measurements, the instrument has to be put in the water, so the reason I had to get close to the water’s edge was to actually put the boat in the water.

JOYCE: Why is having this on-the-ground information so critical?

OVERSTREET: You know, we have models for how ice melts on the surface, and now we’re at the point where we can start to ask the question: how well are the models working? A professor taught me early on that every model is wrong, but some are useful. So we’re trying to get a picture of the Greenland ice sheet hydrology. We’re trying to piece all of this together from the ice turning to water, flowing down into these giant moulins, traversing through kilometers of ice to the base of the ice sheet where it’s expelled as these raging rivers that eventually go to the ocean.

JOYCE: Just to be really clear: the water that’s going into the ice sheet may not be the volume that’s coming out of the ice sheet, because it may be freezing inside the ice sheet? What are the options for what’s happening with the water inside the ice sheet?

OVERSTREET: The refreezing issue is definitely one that’s come up in the last couple of years. Which would lead to a pretty significant delay between what we’re seeing on the ice surface and what’s coming out of the ice. I think the take-home point is that the Greenland ice sheet is incredibly complex. It’s not just these rivers that flow into a pipe that drains directly through the ice.

JOYCE: The NY Times story was interesting because of 1) all of the imagery they included and 2) because I don’t think we don’t normally get to go behind the scenes of science in that way. I’m curious how you felt about the profile and what it says about the work that you are doing.

OVERSTREET: It does such a good job of illuminating that environment. The article, it’s nice that it portrays scientists as real people on the ground. My hope is that the article puts a face on the data that we’re collecting, that it makes it a little more difficult to simply dismiss as data that some scientists are sitting at their computer making up in order to come up these facts about climate change.

JOYCE: Obviously, climate change still generates quite a bit of controversy, especially in places like Wyoming. How does it feel to be in the spotlight?

OVERSTREET: Yeah it’s interesting for me to be thrust into the forefront of the question of climate change, because I’m a river scientist and I’m not used to working in such hot topic areas. And you know, the data that we’re collecting is showing that Greenland is changing much more rapidly than it ever has. And I think these types of studies are absolutely critical for not only understanding what to expect, but being able to prepare for those changes.

JOYCE: I really appreciate you taking the time to speak with me.

OVERSTREET: It was great talking with you.