Accelerated Glacier Loss in Western Canada Revealed Through Trend Analysis of Optical Satellite Imagery

Time-varying glacier inventories can quantify changes in fresh water storage, assess climate change and sea level rise and improve models that simulate future changes in glacier cover. In western Canada, complete glacier inventories exist for the years 1985 and 2005, however. We use optical satellite images from Landsat and Sentinel-2 archives to quantify annual glacier area change for western Canada from 1984-2019. A fully automated workflow is used to map clean ice using a combination of spectral indices and geometric filters. Similar to previous studies, we detect an average annual rate of ice loss of -0.49 ± 0.15% a ^-1 for the period 1984-2008. Over the last decade (2008-2018), however, this rate of ice loss accelerated threefold (-1.54 ± 0.23% a ^-1 ). We also calculate glacier fragmentation and disappearance of glaciers in our study area as well as the total pro-glacial lake area over time. Our work confirms accelerated glacier mass loss revealed for glaciers in western North America; it also provides a reliable method to systematically map and construct time series of glacier change for debris-free ice for most of Earth's mountain ranges.