Mountain Watch provides the first map-based overview of environmental change in mountain regions and its implications for sustainable development. New global maps are presented to illustrate selected values of mountain ecosystems and many of the pressures that are causing environmental change.The global analyses are supported by a range of case studies from different mountain regions, illustrating how environmental assessments can inform the sustainable development of mountain regions. Particular emphasis is given to the use of remote sensing and geographic information system (GIS) technologies, and how these approaches can be used to provide practical tools for decisionmakers, to ensure that development sustains mountain environments and the people that depend on them.The report provides a highly visual, map-based overview of:the ecological and social values of mountain ecosystemscurrent and potential pressures facing mountain environments and peopleapproaches to sustainable development in mountain areasThe researchers collected data on six major pressures on mountains:analysis of seismic hazardsfireclimate changeland cover change and agricultural conversioninfrastructural developmentarmed conflictBy overlaying the biodiversity map with the integrated pressure dataset it was possible to identify mountain areas that support high biodiversity and also experience severe environmental pressures. Among areas of particular concern are:the North-Western Andean moist forest and Magdaleña Valley of South Americathe Caucasus mixed forests ecoregionmontane ecoregions in CaliforniaThese regions are priority candidates for global conservation action in the world’s mountains. [authors]