Recent volume loss of British Columbian glaciers, Canada

We use the Shuttle Radar Topography Mission (SRTM) data and digital terrain models from aerial photography to quantify the change of glacier volume in British Columbia (BC), Canada for the period 1985-1999. We note substantial elevation bias in the SRTM elevations, typically on the order of -12 m km^-1. The bias-corrected thinning rate is -0.78 ± 0.19 m a^-1 which yields an annual volume loss of 22.48 ± 5.53 km^-3a^-1. This rate of glacier volume loss is 65% of the estimate uncorrected for elevation bias (34.7 km^-3a^-1) and cautions against the use of uncorrected SRTM data for glacier change studies. Glacier recession in BC could account for ca. 0.67 ± 0.12 mm of sea level rise over the period 1985-1999 (0.05 ± 0.009 mm yr^-1) or about 8.3% of the contribution from mountain glaciers and ice caps. The recent rate of glacier loss in the Coast Mountains (17.0 km^-3a^-1) is approximately double that observed for the previous two decades.