The Piz Terri and the high Greina plain form a Nature reserve shared between Grisons and Ticino. The Kar Glacier below the Piz Terri has seen a substantial reduction due to global warming. Back in 1865 the glacier filled the area of the entire Lake Kar. This has resulted in massive erosion as the permafrost ground thawed releasing rocks and gravel which has formed a massive landslide below the Piz Terri. Other landslides have covered the remaining Glacier.