Temperature sensitivity of glacier ablation models in high-elevation regions

Abstract. Glacier mass balances in high mountain regions across the world are projected to decline as a result of climate warming. However, the modelled response of glaciers to increasing temperatures depends strongly on the temperature sensitivity of the mass-balance model used. Most modelling studies employ empirical modelling approaches for simulating glacier mass balances, but the effectiveness of empirical approaches has been questioned for high-elevation regions due to a partial decoupling between temperature variations and ablation. This study compares the temperature sensitivities of two empirical and two energy-balance models when applied at high elevations (~6500 m) on the Khumbu Glacier, Mount Everest. The empirical models have a temperature sensitivity more than double that of the energy-balance models when the same warming experiments were applied. This bias indicates that future projections of glacier mass balances in high-elevation regions produced using empirical mass-balance modelling will likely be more negative than if energy-balance approaches were applied, and consequently that existing global mass-balance projections may overestimate future glacier recession in similar high-elevation regions.