The analysis of state-of-the-art regional climate projections indicates a number of robust changes of the climate of the European Alps by the end of this century. Among these are a temperature increase in all seasons and at all elevations and a significant decrease in natural snow cover. Precipitation changes, however, are more subtle and subject to larger uncertainties. While annual precipitation sums are projected to remain rather constant until the end of the century, winter precipitation is projected to increase. Summer precipitation changes will most likely be negative, but increases are possible as well and are covered by the model uncertainty range. Precipitation extremes are expected to intensify in all seasons. The projected changes by the end of the century considerably depend on the greenhouse-gas scenario assumed, with the high-end RCP8.5 scenario being associated with the most prominent changes. Until the middle of the 21st century, however, it is projected that climate change in the Alpine area will only slightly depend on the specific emission scenario. These results indicate that harmful weather events in the Alpine area are likely to intensify in future. This particularly refers to extreme precipitation events, which can trigger flash floods and gravitational mass movements (debris flows, landslides) and lead to substantial damage. Convective precipitation extremes (thunderstorms) are additionally a threat to agriculture, forestry, and infrastructure, since they are often associated with strong wind gusts that cause windbreak in forests and with hail that causes damage in agriculture and infrastructure. Less spectacular but still very relevant is the effect of soil erosion on inclined arable land, caused by heavy precipitation. At the same time rising temperatures lead to longer vegetation periods, increased evapotranspiration, and subsequently to higher risk of droughts in the drier valleys of the Alps. Earlier snowmelt is expected to lead to a seasonal runoff shift in many catchments and the projected strong decrease of the natural snow cover will have an impact on tourism and, last but not least, on the cultural identity of many inhabitants of the Alpine area.
Future Climate Change in the European Alps
Andreas Gobiet and Sven Kotlarski
Impacts of Climate Warming on Alpine Lakes
Martin T. Dokulil
Climate warming has impacted Alpine lakes at all altitudes. The European Alps are particularly affected because the mean temperature increment is twice as high as the global average. Depending on the reduction of greenhouse gases realized in the near future, by the end of the 21st century, Alpine lakes will have warmed above the current temperature by 2–6°C. Extreme weather situations such as heatwaves, droughts, heavy precipitation, and storms are expected to further increase, impacting Alpine regions and lakes worldwide. The expected increase in temperature and the associated impacts on almost all aspects of the ecosystem, together with increasing greenhouse gases and extreme climatic events, will negatively affect Alpine lakes throughout the world.