Christoph Frei from the ETH Zurich showed that on statistical grounds it is not possible to prove or disprove a causal relationship between the accumulation of last year's extreme natural events and climate change. Within a 100-year observation period, the diagnosis of a statistical trend is only possible for frequent events occurring several times a year. An increase in severity of frequently occurring precipitation events was indeed measured in Switzerland.
The second presentation by Martin Kamber of the cantonal reinsurance group discussed the possibilities and limits of insurances issued by private companies. Insurances are well suited to upredictable events, which may harm a large population. If, on the other hand, the occurrence of an extreme event is predictable or if the risk is very unevenly distributed among the insured elements, then insurance is not the right means to protect from losses.