Satellite image analysis of changes in glacier cover in Canada's northern Mackenzie Mountain Range (1987–2017)

Abstract

The state of a group of glaciers in the northern Mackenzie Mountains across the Yukon-Northwest Territories border was investigated over a period of three decades, using Landsat TM and OLI imagery from 1987, 1994, 1999, 2004, 2013, and 2017 to examine changes in glacier extents. A thresholded red/shortwave infrared band ratio image was used to delineate glacier boundaries. The total area of 74 glaciers in the study area decreased from 52.78 ± 1.32 km2 in 1987 to 24.89 ± 0.62 km2 in 2017, a loss of 27.89 ± 1.39 km2 or 52.8 ± 2.6%, with a mean rate of reduction of 1.8% · a−1. Smaller glaciers experienced larger relative changes in area. In this study, the rates of reduction are high compared to decreases reported for other glaciers in the region in the late 20th century. Based on linear extrapolation of the trend in values of total glacier area, it is predicted—subject to uncertainties in how glaciers diminish in size and eventually disappear—that the study area could be free of visible glacier cover within three decades.