Gordon Hamilton
Gordon Hamilton
Polar glaciologist Gordon Hamilton, an associate research professor at the University of Maine’s Climate Change Institute, studies ice sheets and their role in modulating global sea levels. He studies the Greenland and Antarctic ice sheets both in the field and from space. As recently as this past summer, Hamilton was in Greenland, where he has worked for 15 years. There, he pioneered the measurement of extremely fast-flowing outlet glaciers, and was among the first scientists to report an accelerating rate of mass loss from the ice sheet.
How do you describe the changes in the Greenland ice sheet that you’ve seen in the 15 years you’ve been conducting research there?
Greenland has changed dramatically during the time I have conducted research there. The most dramatic changes have occurred where the ice sheet gets funneled between narrow fjord walls and forms outlet glaciers which carry ice from the interior to the ocean. Some of these outlet glaciers have tripled their speed over just a few months. One of the glaciers we are looking at closely, Kangerdlugssuaq Glacier on Greenland’s east coast, accelerated from 5,000 m/yr in September 2004 to 14,000 m/yr by July 2005. That is an extremely fast speed for a glacier–the equivalent of almost half a football field per day! The speed-up of these glaciers has increased the production of large icebergs.
What is the biggest concern about the accelerating rate of mass loss from the ice sheet?
Obviously the biggest concern is a rapid rise in sea level. A decade ago, we were concerned about the Greenland Ice Sheet melting away in a warmer climate, with the liquid water running off into the ocean and raising sea levels. But the recent increases in ice speed mean mass is being added to the ocean much faster, in the form of icebergs. It doesn’t matter if we add this mass in liquid or solid (frozen) form — both displace an equal amount of water (you can do this experiment at home, by checking to see if your drink gets bigger as ice cubes melt). So, if Greenland’s outlet glaciers are speeding up and adding more icebergs to the ocean, sea levels are going to rise.
How did Greenland become one of your two primary research sites and what do you find so fascinating about the country?
If we want to understand how sea levels might change in the coming decades and centuries, we need to look at the largest reservoirs of water, and these happen to be the big ice sheets of Greenland and Antarctica. Despite their large size, our understanding of their behavior is quite limited, so there is no shortage of fascinating science problems to be addressed. Working in Greenland is a special privilege — we get to visit spectacular landscapes rarely visited by anyone else, and we also get to spend time in Inuit villages along the coast.
Based on your research in both Greenland and Antarctica, what’s important for lay people to know/understand about climate change?
People often ask why taxpayers should be funding research in places so remote from the United States, but the simple answer is that whatever happens in places like Greenland and Antarctica, the effects will be felt all over the world, including right here at home. And the changes we are starting to observe in the polar regions are happening much faster than we expected, which shows how sensitive the environment is to relatively small perturbations, such as climate change.
Do you have any predictions about sea level rise in the next decade?
At the current rate of sea level rise, we expect oceans to be a little over an inch higher ten years from now. However, sea level rise is accelerating, so by 2100 we expect sea level to be at least 8-24 inches higher and probably much more.
What can we learn about climate change by viewing Earth from space?
Satellite data gives us the ability to make measurements over much larger spatial scales than we could possibly cover with field programs. Plus, satellites are constantly orbiting Earth, meaning we can obtain data when it is impossible to be in the field.
What are the most extreme weather conditions you’ve worked in?
Probably in Northeast Greenland in early April 1996. I remember trying to get the stove going in the tent for breakfast and the temperature was -59C. We’ve also experienced our fair share of storms, which usually involve digging out tents every couple of hours to prevent them from getting totally buried and collapsing. But I’ve enjoyed just as many picture-perfect blue sky days.
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