Environmental change modelling for Central and High Asia: Pleistocene, present and future scenarios

A regional modelling concept was developed for late Quaternary climate reconstructions and future climate impact assessments. Based on estimates of different climate parameters covering the entire Central and High Asia in a grid-cell spacing of 1?km², climatic determinants of the recent spatial distribution of climate-sensitive environments (glacial and periglacial environments, forest) were explored. Simple climatic threshold functions were established, defining critical climate values for modelling the spatial extension of environments considered. Using palaeogeomorphological indicators as a basis, late Quaternary climatic conditions were modelled in a Last Glacial Maximum (LGM) scenario consistent with palaeogeomorphological and palaeoclimatological data. The results enabled a validation of LGM palaeoclimate simulations performed by the ECHAM GCM. To assess the magnitude of possible future climatic impacts on the spatial distribution of glaciers, permafrost and potential forest stands, two GCM-based IPCC-SRES climate change scenarios (IPCC special report on emission scenarios) for the time period 2070-2099 were considered. Assuming future climates to be perturbed for long enough to affect the environments, a distinct loss of glaciated areas and permafrost must be expected.