glaciaire

Glacier comes from French glacier, a noun derived from glace ('ice'), which comes from Latin glacies ('ice'). Latin glacies is related to Latin gelu ('frost, extreme cold') and the verb gelare ('to freeze'), from a Proto-Indo-European root *gel- meaning cold or to freeze. The same root gives English 'gelatin' (via Latin gelāre, to congeal), 'jelly,' 'cold,' and 'cool' through different phonological paths. The French glacier first named any accumulation of ice — particularly mountain ice — before it was narrowed, in the nineteenth century's systematic natural science, to its precise technical meaning: a large, slow-moving body of ice formed from the compaction of snow over time, which flows under its own weight.

Alpine glaciers were well known to European mountain communities for centuries before they received scientific attention: the glaciers of the Swiss Alps, the French Alps, the Norwegian mountains were part of the lived landscape of mountain peoples, who had names for them in their regional dialects and who understood, from direct experience, that glaciers advanced and retreated seasonally and over longer periods. Swiss naturalist Horace-Bénédict de Saussure undertook systematic study of Alpine glaciers in the late eighteenth century, and his work, along with that of Louis Agassiz in the 1830s and 1840s, established the theory of past ice ages: that glaciers had once covered large parts of Europe and North America. The familiar Alpine ice fields, it turned out, were remnants of an immense continental ice sheet that had shaped the landscape of the northern hemisphere.

Agassiz's 'Études sur les glaciers' (1840) introduced the ice age hypothesis to the scientific world and established the vocabulary of glaciology. The word glacier, applied for centuries to the local ice fields of mountain communities, suddenly named a global process: the periodic advance and retreat of ice sheets across continents, carving valleys, depositing moraines, grinding bedrock, leaving lakes where rock basins had been deepened below drainage level. The Great Lakes, the lakes of Scandinavia and Scotland, the fjords of Norway and Chile, the U-shaped valleys of the Alps — all are glacier products. The mountain ice that Alpine guides had navigated for generations was revealed to be the remnant of an ice age that had reshaped the world.

In the twenty-first century, glacier has acquired a temporal dimension it did not previously have: it has become a symbol of climate change and loss. Glaciers worldwide are retreating at historically unprecedented rates. The Glacier National Park in Montana, named for its glaciers, had 150 glaciers in 1910; fewer than 25 remain. Satellite imagery documents the year-by-year retreat of glaciers in the Himalayas, the Andes, the Alps, and Greenland. The word that named the slow, apparently permanent ice fields of the world's mountains now names something visibly impermanent. 'Glacial pace,' the idiom for extreme slowness, has begun to acquire an ironic precision: glaciers are, in fact, moving faster than they used to, as the meltwater at their base lubricates their movement even as they diminish.