Rate of Growth or Shrinkage of Nonequilibrium Ice Sheets

Abstract

AbstractAn analysis is made of the time required to build up an ice-age ice sheet and of the time required to destroy such an ice sheet. The calculations are based on the approximation that the theory of perfect plasticity is valid. It is concluded that the time required to build up an ice-age ice sheet is longer than the time required to eliminate it. If it is assumed that the accumulation rate of an ice-age ice sheet lies in the range of 0.2 to 0.6 m./yr., it is found that the growth time of a large ice sheet is of the order of 15,000 to 30,000 yr. Ablation rates of to 2 m./yr. lead to shrinkage times of the order of 2,000 to 4,000 yr., provided ablation occurs over an appreciable area of the ice sheet.