Glacier Length Sensitivity to Climate Change in Different Climate Regimes

Abstract:

Current decreases in mountain glacier length can indicate contemporary climate change, but the magnitude of glacier retreat may depend on the climate regime that a glacier inhabits. Previous studies have shown that the sensitivity of the glacier mass balance to climate change varies based on climate regime. Here, we quantify the glacier length sensitivity to temperature and precipitation rate changes for idealized glaciers in the inner-tropics, outer-tropics, sub-tropics, and mid-latitudes, using a 1-D flowline model coupled to an energy balance model for ablation. We find that mid-latitude climate regime glaciers are the most sensitive to temperature changes and that sub-tropical climate regime glaciers are the least sensitive (Figure a). We find that sub-tropical climate regime glaciers are the most sensitive to precipitation rate increases and that mid-latitude climate regime glaciers are the least sensitive to precipitation rate decreases while inner-tropical climate regime glaciers are least sensitive to precipitation rate increases. Also, we find in some climate regimes that the direction of climate change (warming vs. cooling or increased precipitation vs. decreased precipitation) affects the magnitude of the glacier length response, suggesting feedbacks and non-linearities. With the exception of sub-tropical climate regime glaciers, of which there are few, glaciers in all other climate regimes retreat more due to a 1°C warming than advance due to a doubling in the precipitation rate, suggesting that continued glacier retreats will be a robust trend given current climate trends.