Climate is an important driver for erosion and has direct hydrogeological and geomorphological effects, in particular related to glacial erosive and depositional processes. Considering the present-day climate assessment and projected conditions regarding future climate states in the Alpine realm, the conclusions are:

  • Glacials are of fundamental importance with respect to erosion processes in Northern Switzer­land.

  • The palaeoclimatic record and simulations of past Quaternary climates show that the global as well as the local climate evolution of Northern Switzerland was dominated by a succession of glacial/interglacial cycles. Before the Mid-Pleistocene Transition (between 1.25 and 0.7 Myr), these cycles lasted approximately 41 kyr, while after the transition 100-kyr cycles became dominant.

  • Using the geological and geomorphological record, especially for the last glacial/interglacial cycle, the ice extent in the greater Switzerland area can be mapped and simulated. Glaciers reached far into the Alpine Foreland, repeatedly covering Northern Switzerland.

  • The ZNO siting region and partly also NL were covered during LGM-size glaciations, while JO remained ice-free. ZNO and NL were covered by the Beringen Glacial. JO is only covered by exceptionally large foreland glaciations, such as the Möhlin Glacial.

  • During the coldest time intervals, permafrost north of the Alps was continuous, cold (mean annual surface temperature about -5 °C with shorter-term extremes down to -10 °C) and reached depths of about 100 to 200 m

  • Ice-flow modelling allows estimation of the erosion potential in Northern Switzerland during foreland glaciations; basal ice temperature and sliding speed are key variables for glacial erosion. Ice was channelled along troughs; these sliding conditions may have favoured glacial erosion. High subglacial water discharge is key to removing basal sediments, exposing bedrock and favouring further glacial erosion.

  • A maximum ice thickness of ~ 200 – 400 m and a duration of ice occupation of ~ 1'000 – 3'000 yr in ZNO and NL were simulated and are expected for future foreland glaciations.

  • Insolation is one of the main climate drivers and can be calculated accurately for the future. The atmospheric CO2 concentration has a very strong influence on the timing and severity of future glaciations. Only if the greenhouse gas concentration is reduced to pre-industrial levels, will the next glaciation be expected to occur at around 100 kyr after present. An additional 500 PgC will postpone the next larger glaciation to > 200 kyr. Even higher total carbon emissions will move the onset of the next glaciation further into the future.

  • After a glaciation, the climate warms, and climate conditions change from a polar climate (Switzerland largely covered by ice and/or permafrost conditions) towards a continental, temperate or potentially an even warmer-drier climate.