The response of individual glaciers to climate change

For individual ice masses, ground- and satellite-based meteorological and snowpack observations can be combined to provide quantitative insights about the climatic controls of mass balance. Field-based mass balance measurements are frequently co-ordinated with energy balance studies at a site (cf. case studies of Klok and Bintanja, this volume, Chapters 33 and 34). Over a number of years, this gives insights about the relative influence of precipitation versus temperature in governing interannual mass balance variability. To illustrate this, Fig. 32.1 plots the winter, summer and annual mass balance record of the Peyto Glacier, Canadian Rockies, for the period 1966-1995 (Demuth & Keller, 1997). Linear correlation analyses on the winter and summer versus net annual mass balance indicate that both the melt season and the accumulation season are important for net annual balance at this site (r = 0.77 for the summer balance and r = 0.67 for the winter balance).

This gives evidence of the important roles of both maritime influences (precipitation) and continental influences (the length and strength of the summer melt season) on the Peyto Glacier. Numerous in-depth mass balance/climate studies relevant to this site and to western North America have been carried out (e.g. Yarnal, 1984; Letreguilly, 1988; Demuth & Keller, 1997; Hodge et al., 1999; Bitz & Battisti, 1999). Studies of this sort have been done in most of the world's glaciated regions, providing a large knowledge base on local-scale meteorological controls of mass balance for a small number of ice masses that are possible to monitor. Climate-change sensitivity can be estimated reasonably

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