Animation S1: Animation showing MODIS imagery and edge detection for Kangerdlugssuaq glacier. Left hand plot shows band 1 surface reflectance of Kangerdlugssuaq and the surrounding area for each cloud free day, which forms a single frame of the animation; axis units are km. Central top figure shows surface reflectance of the 'active region', the area within which edge detection takes place; axis units are km. Second central figure down shows detected edge pixels (white) over the active region using the Sobel method; axis units are km. Third central figure down shows frequency of detected edge pixels (y-axis) using the Sobel method along the length of the glacier (x-axis, km). High frequencies signify likely calving margin positions. Central bottom figure shows gradient (y-axis) of across-glacier averaged surface reflectance along the length of the glacier (x-axis, km), used as part of the brightness profiling method of calculating margin position. High brightness gradient locations signify likely calving margin locations. Right hand plot shows detected margin positions after consolidation of the two detection methods and noise removal procedures; x-axis is relative margin position in km, y-axis is time in years beginning. A horizontal line travels down the plot to signify animation location within time. Animation S2: Plots are the same as in Supplementary Animation S1, but for Helheim Glacier. Plot details are described in the caption for S1.