To calculate the ICAF, data over a long observation period are used, from 1961 to 2022. The period 1961-1990 serves as a reference history, for the calculation of the different values of the index from 1991 to 2022. The ICAF is therefore calculated monthly and year by year on geographical areas covering 0.25° (longitude) by 0.25° (latitude). Refinement is possible for smaller exposure areas, i.e. 0.1° (longitude) by 0.1° (latitude).
Figure 1: Evolution of the switzerland phone number list Actuarial Climate Index France - Reference period 1961-1990 and monthly calculations between 1991 and 2022
(Source: Garrido, X. Milhaud, and A. Olympio. On the definition of a French actuarial climate index, 2023.)
The ICAF upward trend indicates an increase in extreme climate events (frequencies, levels, etc.) over time.
Each of the components was selected for two reasons. The first is that they all have consequences for health, property and people. The second is that the data used to define them are public and freely accessible, and at a sufficient level of spatio-temporal meshing to carry out local (by department) and dynamic (over the long term) analyses.
By combining the different components in the ICAF, it allows to measure the climate risk on the basis of a basket of extreme climatic events and variations in sea level. An increase in the seasonal value of the ICAF indicates an increase in the number of extreme climatic events, and therefore an increase in damage to property and people.
Heat spikes have very harmful effects on mortality, especially among vulnerable people, because there is a strong relationship between heat and excess mortality. Conversely, cold spikes and their progressive decrease have impacts on many living species, including some plants that need a cold period to germinate and flower (a phenomenon called vernalization) [3] .