Abstract
Mountain regions are biodiversity hotspots, support a great diversity of habitats and species, and provide numerous ecosystem services for lowland areas. At the same time, mountain areas are very sensitive environments because of their peculiarities, and are considered as sentinel of climate changes. In fact, despite large uncertainties (Kohler et al., 2014; Stocker et al., 2013), the temperature increase in mountains doubles the global average (Kohler et al., 2014) and several parameter changes (e.g., albedo, snow cover) intensify with altitude (Notarnicola, 2020; Pepin et al., 2015). The importance of mountains is acknowledged and supported by numerous global initiatives. The United Nations included mountain ecosystem conservation in its Sustainable Development Goals and in 2019 the GEO Mountain called for the identification of Essential Climate Variables (ECVs) and Biodiversity Variables (EBVs) for high altitudes (Adler, 2018a, 2018b; Shahgedanova et al., 2021; Thornton et al., 2021). Moreover, GEO Mountain is aiming at supporting the different UN frameworks and has a relevant role in several policy agendas such as the Intergovernmental SciencePolicy Platform on Biodiversity and Ecosystem Services (IPBES), the Sendai Framework for Disaster Risk Reduction, the Paris Agreement, and assessments of the Intergovernmental Panel on Climate Change (IPCC). With the advent of the Copernicus era, Earth Observation (EO) tools in terms of imagery, platforms, and software offer a unique opportunity to continuously monitor the mountain environment and provide valuable information for its protection and safety. This chapter addresses the current and future challenges of EO observations in the different sectors, going from the cryosphere to water resources and agriculture, to ecosystems, and to gravity-driven natural hazards. Current data and processing platforms are presented to provide an overview of the plethora of information and tools now made available to researchers and practitioners. In this chapter, we selected these sectors based on our experience in several national and international projects, where EO data play a major role. Moreover, the analysis of these sections can provide a connection thread on how the changes in snow and glaciers impact the water resources and then consequently agriculture and ecosystems. It is out of the scope of this chapter to draw a complete picture of all the sectors that can be affected by climate changes.