Storylines of future climate extremes in Switzerland

Storylines provide a way to communicate climate change and especially changes in extreme events in a tangible way for the public and decision makers by putting the focus on associated risks and impacts. In this work, storylines are created for the 2003 summer heatwave in Switzerland. For this purpose, an analogous event is searched for in the already existing Climate Scenarios for Switzerland (CH2018). This event shall be as extreme in the future climate as 2003 was in its time. Building storylines for this future extreme event, we demonstrate how a 2003-like summer might be like by the end of the Century assuming no climate change mitigation. Specific indicators are chosen to develop four individual heat-related storylines and enabling a direct comparison between 2003 and the future hot summer. For the future summer, the number of hiking weather days in the Alps is projected to increase on the one hand, while on the other hand also fire danger increases massively. More and longer heatwaves may aggravate heat-related health issues and additional generations of agricultural pests could threaten agricultural yields.

With these storylines of a similar future heatwave, we gain a better understanding of locally relevant processes, get insight into how extreme events quantitatively change with the warming climate, give examples of possible impacts, and finally try to stimulate public awareness for possible consequences of future climate change. We explore different ways of visualizing and communicating the results, which may find broader application to inform Swiss stakeholders about future climate change and its possible impacts.