Perturbation analysis is applied to the heat balance at the EGIG line
(West Greenland) with respect to climatic changes. The shift of the eq
uilibrium-line altitude is obtained for perturbations of temperature,
absolute humidity, cloudiness and annual accumulation. The total net i
ce 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.