Predicting the response of seven Asian glaciers to future climate scenarios using a simple linear glacier model

Abstract

Observations from seven Central Asian glaciers (35–55N; 70–95E) are used,together with regional temperature data, to infer uncertain parameters for a simple linearmodel of the glacier length variations. The glacier model is based on first order glacierdynamics and requires the knowledge of reference states of forcing and glacierperturbation magnitude. An adjoint-based variational method is used to optimallydetermine the glacier reference states in 1900 and the uncertain glacier model parameters.The simple glacier model is then used to estimate the glacier length variations until2060 using regional temperature projections from an ensemble of climate modelsimulations for a future climate change scenario (SRES A2). For the period 2000–2060,all glaciers are projected to experience substantial further shrinkage, especially those withgentle slopes (e.g., Glacier Chogo Lungma retreats 4 km). Although nearly one-thirdof the year 2000 length will be reduced for some small glaciers, the existence of theglaciers studied here is not threatened by year 2060. The differences between theindividual glacier responses are large. No straightforward relationship is found betweenglacier size and the projected fractional change of its length.