Exposure of global mountain systems to climate warming during the 21st Century

We provide an assessment of surface temperature changes in mountainous areas of the world using a set of climate projections at a 0.5 degrees resolution for two 30-year periods (2040-2069 and 2070-2099), using four Intergovernmental Panel for Climate Change (IPCC) emission scenarios and five AOGCM. Projected average temperature changes varied between +3.2 degrees C (+0.4 degrees C/per decade) and +2.1 degrees C (+0.26 degrees C/per decade) for 2055 and +5.3 degrees C (+0.48 degrees C/per decade) and +2.8 degrees C for 2085 (+0.25 degrees C/per decade). The temperature is expected to rise by a greater amount in higher northern latitude mountains than in mountains located in temperate and tropical zones. The rate of warming in mountain systems is projected to be two to three times higher than that recorded during the 20th century. The tendency for a greater projected warming in northern latitude mountain systems is consistent across scenarios and is in agreement with observed trends. In light of these projections, warming is considered likely to affect biodiversity (e.g., species extinctions, changes in the composition of assemblages), water resources (e.g., a reduction in the extent of glaciated areas and snow pack), and natural hazards (e.g., floods). Accurate estimate of the effects of climate change in mountain systems is difficult because of uncertainties associated with the climate scenarios and the existence of non-linear feedbacks between impacts. (C) 2006 Elsevier Ltd. All rights reserved.