Seasonal dynamics of Earth’s glaciers and ice sheets

The sensitivity of Earth’s glaciers to environmental change is on display each year as they change speed with the seasons, and a glacier’s response to warming from winter to summer may help predict its response to warming on multi-year timescales. We present the first global analysis of seasonal glacier and ice sheet dynamics, finding that seasonal velocity amplitudes are greatest where annual maximum surface temperature exceeds 0°C. We see evidence of basal hydrological systems impacting glacier flow on seasonal timescales, and we find a global correlation between seasonality and interannual flow variability. Relationships in the data suggest that projected atmospheric warming could amplify and alter the timing of seasonal glacier dynamics worldwide, and changes in seasonality could portend further sensitivity to warming.