Switzerland is mostly colored orange on the federal government’s hazard maps for heat and forest fires – this means there is a significant risk. Politicians are already calling for a national concept to ensure the drinking water supply throughout the country. And the temperatures are expected to increase this week: SRF Meteo forecasts up to 38 degrees locally for Tuesday. What may make bath-hungry happy, causes others to worry – such as climate historian Christian Pfister.
SRF: Such heat and drought, has that ever happened in Switzerland?
Christian Pfister: Together with climatologists, we have examined the last thousand years in a book. In doing so, we found that there were various such events. Among other things, the year 1540 has been particularly well studied. We had heat and drought in a large area of Europe: from Spain to Poland, from northern Italy to northern Germany.
How did that show up, what happened there?
The event lasted for a month, peaking in July when there was no rain either, but with much higher temperatures. There were widespread wildfires resulting in dry fog. Fog was observed from Switzerland to Poland.
Do you have to expect such consequences now?
So far I don’t think so, but we can’t make any definite statements. If extremely warm air comes, that would still be possible. But I hope it doesn’t come to that.
What factors lead to situations like the current one, i.e. to fires?
There is an accumulation of cases with a dry spring, which then turns into a warm, hot summer. The conditions in spring therefore determine whether summer will be extreme or not. However, absolutely certain correlations cannot be derived. After a very dry spring, however, there is a greatly increased risk of having a summer like the one we are having now.
In the recent past we have seen various heat record years: 2003, 2015, 2018, 2019. Is what used to be exceptional slowly becoming normal?
That’s so. In terms of climatology and climate policy, we only ever discuss average values. But extreme events are significant for the population, nature and the environment. If the mean shifts, then we have more extreme events and ever more extreme extreme events – including those that are not found in the meteorological measurements of the last centuries. You would have to go way back in history.
So these events are coming anyway, how can we adapt?
First and foremost, it is important to remember that such events can occur. And it’s important that the authorities think about what to do in such situations so that they aren’t caught off guard. For example, dry wood could be cleared from the forests to prevent forest fires.
Arthur Honegger conducted the interview.