Climatic knowledge of mountain regions is limited by paucity of observations and insufficient theoretical attention to processes within these regions. Areas where our theoretical understanding is incomplete include orographic precipitation, especially extreme events, pollutant transport and deposition, and effects of forest cover on evapo-transpiration and runoff.Direct and indirect evidence of past climatic conditions in many mountain areas of the world suggests substantial changes over the last one hundred years, as indicated most strikingly by glacial recession. Modeling approaches to assessing potential future climatic states are discussed in the context of mountain areas. Reductions in snow cover duration and changes in the amount of timing of snow melt runoff are described.The survey concludes with a series of recommendations for necessary actions to improve our capabilities for monitoring and detecting climatic changes in mountain areas and for assessing their significance and possible impacts.
