Abstract
Perturbation analysis is applied to the heat balance at the EGIG line (West Greenland) with respect to climatic changes. The shift of the equilibrium-line altitude is obtained for perturbations of temperature, absolute humidity, cloudiness and annual accumulation. The total net ice ablation at the EGIG line increases by 45% with a perturbation of + 1 K. Applying this figure to the entire ice sheet, the total ablation equals the total accumulation at a warming of + 2 K, if refreezing of melt water is neglected.