Recent changes in glacier area and volume within the southern Canadian Cordillera

Net changes in glacier area in the region 50-51 degrees N, 116-125 degrees W, which includes the Columbia and Rocky Mountains (1951/52-2001) and the Coast Mountains (1964/65-2002), were determined through a comparison of historic aerial photography and contemporary Landsat 7 ETM+ imagery. The volumes of individual glaciers were estimated using an empirical volume-area scaling relationship. The area of glaciers in the Coast Mountains decreased by 120 +/- 10 km(2), or 5% of the initial ice-covered area here. The areas of glaciers in the Columbia and Rocky Mountains decreased by 20 and 6 km(2) respectively, corresponding to relative changes in total area of -5% and -15%. The estimated total ice volume loss from the whole region was 13 +/- 3 km(3). In all parts of the study area, the relative changes in area of individual glaciers showed considerable variability, while the smallest glaciers remained essentially unchanged. This suggests that local factors unique to individual glaciers largely determine their sensitivity to climatic change, and that the very small glaciers are collectively less sensitive to such change.