A set of mid-range unmitigated climate change scenarios suggest temperature increase of 3 °C to 6 “C toward the end of the century, depending on the season and part of the country. Changes in summer are the most uncertain. The largest lake within EU, Lake Vanern, and its outlet, River Gota alv, constitute a complex system, where risks for flooding and landslides may increase. The city of Stockholm is located at the outlet of the lake, which provides water supply for some 2 million people in the metropolitan area.