Local glaciers receding due to climate change

Ken Smith/Turnagain Times Glaciers in the surrounding valleys of Turnagain Arm and the state of Alaska are receding at a dramatic pace due to global warming. The retreat of Portage Glacier (above) is an example of one of the more obvious changes being experienced by local glaciers

By Tom Yeager
Special to the Turnagain Times

The dramatic retreat of Portage Glacier has given long-term residents of Turnagain Arm a front row seat for observing the impact of climate change.
Thirty years ago, a ski trip across Portage Lake involved navigating through a stalled parade of frozen-in-place icebergs to the dramatic face of Portage Glacier, which then stretched a mile and a half between the sheer cliffs bordering both sides of the lake. Today that same winter excursion involves skiing across a much larger lake to a much less imposing glacier.
The retreat of Portage Glacier may be one of the more obvious changes being experienced by our local glaciers, but it is by no means unique. It appears that virtually all of our neighboring glaciers, while still impressive, are in an accelerating process of becoming mere remnants of their former glory.
As they exist today, our surrounding glaciers are vestigial remains of ancient ice sheets that once dominated this area. They owe their continued existence to the unique combination of our maritime climate, our Northern latitude, and the altitude of the Chugach Mountains. Their future is, however, uncertain.
The entire State of Alaska has, depending on who is doing the counting, as many as 100,000 glaciers covering approximately 29,000 square miles. While these numbers may pale when compared to Antarctica and Greenland, our state is noteworthy for the many different types of glaciers found here. We have high altitude and low altitude glaciers, tidewater and inland glaciers, small cirque and massive piedmont glaciers. We even have surging glaciers, and a few contrary glaciers that are bucking the general trend by increasing their mass and advancing their termini.
But despite some excellent work by a number of state, Federal and private organizations, there are only two Alaskan glaciers (Wolverine Glacier near Seward and Gulkana Glacier near Paxton) that have had long term and continuous monitoring.
Particularly during this time of accelerated glacier melting, the nearly ubiquitous retreat of Alaska’s glaciers is an important subject for scientific study. In an attempt to gain some insight into what is happening to a couple of our local glaciers, two separate, but coordinated, scientific inquiries were initiated this past summer.
A team of students from Alaska Pacific University, led by professors Michael Loso and Eeva Latosuo, conducted glaciological studies while making the traverse from Girdwood via Eagle Glacier and Whiteout Glacier to the terminus of Eklutna Glacier.
Concurrent with the APU field work, Research Assistant Professor Chris Larsen at the Geophysical Institute, University of Alaska Fairbanks, made a series of airborne monitoring flights over Eagle and Eklutna glaciers capturing precise measurements of the contours of both glaciers.
An initial analysis of the data collected this summer by the APU and UAF teams indicates that the ice thickness of some areas of both Eagle and Eklutna glaciers has been reduced in recent decades by an amount that will be measured in hundreds of feet.
Looking forward, this summer’s findings serve as an accurate baseline for comparison with future data on these two glaciers. The magnitude of ice lost by our backyard glaciers emphasizes the need to ensure that this data collection continues, and that it be expanded state-wide in order to better understand Alaska’s glaciers and their future response to climate change.
As validated by this summer’s activity, Girdwood is uniquely positioned both geographically and logistically to play a continuing role in the effort.