By Dr. Robert Thorson
Harvard advances. Yale retreats.
I’m not talking about the annual football game between the Harvard Crimson and the Yale Bulldogs, scheduled for Nov. 18. I’m talking about two tidewater glaciers in Prince William Sound, Alaska, one named Harvard, the other Yale. Knowing something about the forward and backward behaviors of these twin glaciers can help expose specious arguments about climate change being perpetrated by tabloid-style media and by so-called scientists in the pocket of the fossil fuel industry.
The glacier game is being played in College Fjord, “discovered” and named by the 1899 Harriman expedition. Among those participating in this early version of a luxury cruise were the writers John Muir and John Burroughs, and the scientist Grove Carl Gilbert, patron saint for process-oriented, rather than historical, geologists. Upon encountering dozens of previously unknown glaciers, the participants decided to name the prominent glaciers after the colleges and universities that helped finance the expedition. In an early expression of gender equity, those glaciers to the west were named after women’s colleges, those to the east after men’s colleges.
Near the head of the fjord were two glaciers draining the same ice field. In what was probably an arbitrary decision like the ritual coin toss at the start of a football game, one glacier was named Harvard, the other Yale.
Thus began the glacial version of the Harvard-Yale intercollegiate rivalry. The academic competition is well known. Both schools are running neck and neck, with Harvard being ranked No.2 to Yale’s No.3 according to this year’s U.S. News & World Report rankings. In the schools’ football history, Yale has the advantage, having won 64, lost 50 and tied eight games through the most recent season. But in the glacial race, Harvard is the runaway winner.
Despite the dramatic loss of icebergs from its tidewater terminus, Harvard Glacier has actually been moving forward about 20 meters per year since 1931, a trend that began before 1905. Meanwhile, the terminus of the Yale Glacier has been moving backward about 50 meters per year. Converting these annual movements to the football field, Yale’s loss is equivalent to Harvard making an endzone interception and running it back to midfield. Harvard’s gain is equivalent to Yale having been called for pass interference and illegal motion on subsequent downs.
The retreat of Yale glacier is consistent with the fate of most tidewater glaciers elsewhere in Alaska, as well as the recession of continental mountain glaciers, ice caps on tropical volcanic summits and the margins of large ice sheets near sea level. The overwhelming tendency toward glacial retreat is consistent with and driven by the global warming trend that began at the end of the Little Ice Age, about 1850 AD, one being amplified by anthropogenic greenhouse emissions.
Glacial scientists aren’t bothered by the seemingly contradictory behavior of Harvard Glacier. Other variables besides the rate of terminal melting are involved, for example: the bathymetry or shape of the fjord below the ice, which determines the rate at which icebergs are launched; the amount of meltwater beneath the higher, colder accumulation zone, which determines how easily the ice can slide; or the down glacier passage of a dynamic (kinematic) wave. Nor are scientists bothered by the gain of ice in some inland glaciers, especially those with bitterly cold accumulation areas such as the East Antarctic Ice Sheet.
If you understand these nuances of glacial physics, you’ll be able to spot a disingenuous climate scientist citing the contrarian behavior of a few glaciers to suggest that the world’s glaciers aren’t melting that fast after all. Hopefully, you will also be able to spot an ill-informed reporter making much fuss about the non- existent controversy that glaciers can’t make up their mind about how to respond to global warming.
There are winners and losers for every turn of events, whether on the college football field, or in College Fjord. The football will continue. What may not continue is the game of glacier watching, at least from accessible places. Sadly, these beautiful features are dwindling and disappearing.