The European Arctic and Alpine regions are experiencing large environmental changes. Increased temperatures and precipitation, reduction in sea ice and glacier ice, the increased level of UV-radiation and the long-range transported contaminants are challenging new stress factors for both terrestrial and aquatic organisms. The large annual variation in the physical parameters of these extreme environments is also a key factor in structuring the biodiversity and biotic productivity, and the effect of the stress factors can be critical for the population structures and the interaction between species. These changes may also have socio-economic effects if the changes affect the bioproduction, which form the basis for the marine and terrestrial food chains. This book gives an integrated overview of the contemporary environmental changes in Arctic, Alpine Regions; Climate Change and Ecosystem Response, Long Range Transport of Pollutants and Ecotoxicology, UV-radiation and Biological Effects, Socio-economic Effects of Environmental Change.