Projections of the probability of the "Elfsteden" ice skating tour under future climate scenarios using lake models

The Elfstedentocht is a culturally significant long distance ice skating tour held in Friesland, the Netherlands. The frequency of the tour has been declining over the last century due to increasingly mild winters. This study investigates the probability of an "Elfsteden" ice skating tour under different future IPCC climate scenarios: SSP1-2.6 (low emissions), SSP2-4.5 (intermediate emissions) and SSP5-8.5 (high emissions). Two different ice growth models are employed to produce projections of ice thickness for the future. The ice growth models are driven by sub-daily meteorological forcing from the regional climate model RACMO2, which in turn is driven on its boundaries by global reanalysis model ERA5 and 16-member ensemble climate model EC-Earth3. Even under the low emissions scenario, the average number of Elfsteden tours is found to be only 1.6 to 1.8 over the period 2020-2100. For the intermediate emissions scenario, the average number of tours is 1.6 and 1.4 over that same period, and for the high emissions scenario, models predict only 1.3 and 1.4 tours on average. The values found are lower than statistical estimates from previous research, likely due to how a changing climate affects statistical and physical models. Analysis of yearly probabilities per decade show that the likelihood of a tour becomes virtually zero by the end of the century for the intermediate and high emissions scenario, but stays relatively stable for the low emissions scenario. The results highlight the vulnerability of cultural events such as the Elfstedentocht in a changing climate.