Seeing glacial change: optical consistency through the camera and the archive

Martin Mahony

The Gangotri glacier in India, source of the Ganges river. Source: Wikimedia Commons

Towards the end of last year I visited an exhibition at the Massachusetts Institute of Technology (MIT) Museum entitled ‘Rivers of Ice: Vanishing Glaciers of the Greater Himalaya’. The exhibition presented the work of mountaineer, photographer and filmmaker David Breashears, who had recently trekked through the Himalaya to produce updated photographs of glaciers which had been caught on film by earlier explorers. The exhibition blended the scientific iconography of climate change with that of the intrepid explorer, with the ice picks and ropes of the geographic expedition juxtaposed against the graphs and satellite imagery of climate science (see here).

My interest in glaciers grew from some empirical work I’ve been conducting on the contestation between the Intergovernmental Panel on Climate Change and the Indian government over the possible rapid melting of Himalayan glaciers. In the IPCC’s 2007 report, it was asserted that the glaciers could entirely disappear by 2035. This claim was refuted by a government-sponsored review conducted by an Indian glaciologist, which reported a mixed pattern of advancing and receding glaciers and challenged “the conventional wisdom” of climate change causing rapid melting, as the Environment Minister Jairam Ramesh put it. The 2035 claim was later revealed to be ill-founded, having been picked-up from a magazine interview with a glaciologist in the 1990s and eventually finding its way into the IPCC report.

Melting ice has become a visual icon of climate change. Images of polar bears stranded on diminished ice floes and juxtaposed ‘then-and-now’ photographs of shrinking glaciers often dominate media coverage of the issue. There is something very tangible about disappearing ice, perhaps because its relationship to warming temperatures is much more direct and imaginable than the more complex causal links between global warming and the occurrence of extreme weather events. The vulnerability of ice to human-generated heat neatly captures the sense that human activities are impinging on and endangering a fragile natural world.

Scientific knowledge of melting ice is, however, deeply complex. As shown by the IPCC incident, it also sometimes the topic of heated scientific and political debate. In a recent paper in The Geographical Journal, Ulrich Kamp and colleagues provide a window onto the complex methods of detecting change in mountains glaciers, while also offering a fascinating account of how different sorts of data can be combined to produce new scientific understandings. The authors visited the RGS archives in London to access data and photographs from a 1910 RGS expedition to the Turgen Mountains in Mongolia led by Douglas Alexander Caruthers (1882-1962). After reviewing field notes and photographs from the expedition, the authors made their own way to the Turgen Mountains to reproduce the images made by Caruthers and his team.

By carefully positioning and calibrating their cameras, Kamp’s team was able to produce images suitable for detailed comparison. The anthropologist and philosopher of science Bruno Latour has often noted how much scientific knowledge production depends on achieving “optical consistency”, in order to find regular avenues through geographic space. The optical consistency achieved by the 21st century explorers enabled them to compare the pixels of their new images with scanned versions of the 1910 pictures, in order to ascertain precise measurements of ice loss. The authors are then able to conclude that glaciers on the lower slopes of the mountains have shown a marked retreated over the course of the last 100 years, and that continuing climate change will likely see that trend continue.

The image of the geographer-as-explorer has long since receded from imagination (at least those of academic geographers). However, Kamp et al.’s study demonstrates that where a key variable of scientific research is the passage time, there is great value in revisiting the archived work of geographers of old.

globe42

India ‘arrogant’ to deny global warming link to melting glaciersThe Guardian

globe42 IPCC officials admit mistake over melting Himalayan glaciersThe Guardian

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Ulrich Kamp et al., 2013, Documenting glacial changes between 1910, 1970, 1992 and 2010 in the Turgen Mountains, Mongolian Altai, using repeat photographs, topographic maps, and satellite imageryThe Geographical Journal, DOI: 10.1111/j.1475-4959.2012.00486.x

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