A recent letter here from Mr. J. Sawyer expresses his skepticism about the rates of glacial retreat, particularly in Glacial National Park. He doesn’t include his sources, but regardless it’s fair to say that a large percentage of voters, most of them affiliated with the GOP, agree broadly with Mr. Sawyer’s position. So I’d like to present here a few reasons why Mr. Sawyer’s skepticism is, to me, ill advised.
1. There are several news items (Google) about huge — the size of Manhattan or Connecticut — chunks of shelf ice in the Antarctic that have either broken off or in NASA’s view are about to.
2. Half a dozen islands in the Solomons are being inundated and could be entirely covered by the Pacific Ocean in this century. The government of Kiribati has recently solicited the U.N. to finance the relocation of its citizens.
3. In a recent New York Times story, Highway 80, the only road to and from a popular offshore Georgia island, has to be closed several times a year now due to high tides.
4. The History Channel has been doing a “reality” program called Ice Cold Gold that takes place in western Greenland (out of Nuuk). The background for the episodes and my brief conversations with the geologist and a cinematographer make clear that the various small-scale mining efforts have become feasible due to the recent melting of Greenland’s ice sheet.
These are all admittedly anecdotal observations. So let me shift the focus now to some of my personal experiences. When I took an Inland Passage cruise in 2011 a National Parks Service ranger came on board in Glacier Bay to answer questions. He said that more than 90 percent of the world’s glaciers are in retreat. This can be verified by examining aerial and satellite photography.
For one example, consider the report done by the University of Alaska SE on the Mendenhall glacier near Juneau (source: www.uas.alaska.edu/envs/links.html). Its average rate of retreat from 1997 to 2008 was 158 feet per year. Photos show the terminus of this glacier now about two miles from the Visitor Center where it was when the center was built in 1962. This gives the rate of retreat over the past 54 years as 194 feet per year. Wikipedia gives a retreat of 1.75 miles since 1929, which would be 107 feet per year. This suggests an acceleration in the rate of retreat.
In 2011, I also visited a few glaciers in Alberta. When you drive to the parking lot for the Athabasca glacier, you pass signs that say “The glacier was here in (Le glacier état ici en)” followed by a year. At the 1908 sign, the parking lot is not visible and the glacier looks 2-3 miles away. The 1982 sign is on the trail past the parking lot to the glacier. I happened (no trail) on a pedestal with just “2000” on it, about 100-150 yards from the ice. So roughly 400 feet in 12 years would be 33 feet per year. This is a typical figure for glacial retreat in North America.
The Exit glacier (outside of Seward) also has signs with years marking where the nose used to be. The 1917 sign is next to a smooth, wide, asphalt part of the trail. By the 1961 sign the trail is no longer asphalt but the ice is nowhere to be seen yet. Just before a short walk to the glacier a sign reads “Exit Glacier Was Here,” then “If you had been standing here in 1998 the ice would have been right at your feet….”
Mr. Sawyer can choose to draw the kinds of conclusions the vast majority of earth scientists and others have drawn or he can choose to continue in his skepticism. It makes no difference. The ice continues to melt and the seas continue to creep higher. If you believe these changes have not been accelerated by our burning of fossil fuels, in my opinion you haven’t been paying attention.
Bob Wilson lives in Boulder.
