The potential impact of climate change on seasonal snow in New Zealand: part Ⅱ-industry vulnerability and future snowmaking potential

摘要

Seasonal snow in New Zealand is likely to be subject to substantial change due to the impacts of climate change. These changes will have wide ranging impacts on the New Zealand's economy through the energy, agricultural and tourism sectors. In this paper, we assess the impact of climate change, at a micro-scale for a selection of ski area locations in New Zealand. Where available, we have used current observations of snow depth to calibrate the snow model output for the current climate. We consider the change in the number of days with snow depths exceeding 0.30 m, 'snow-days', at each of these locations for the 2030-2049 (mid-point reference 2040) and 2080-2099 (mid-point reference 2090) time periods, for the three different emission scenarios (B1, A1B and A1FI). These future scenarios are compared to simulations of current, 1980-1999 (mid-point reference 1990), number of snow-days at these locations. We consider both an average year in each 20-year period, as well as a 'worst-case' year. At each ski area, we consider an upper and lower elevation site. Depending on the elevation and location of the specific site, our analysis shows that there will be a reduction in the number of snow-days in nearly all of the future scenarios and time periods. When we consider a worst-case or minimum snow year in the 1990s, the number of snow-days at each site ranges from 0 to 229, while by the 2040s, it ranges from 0 to 187 (B1), 0 to 183 (A1B) and 0 to 176 (A1FI). By the 2090s the number of snow-days ranges from 0 to 155 (B1), 0 to 90 (A1B) and 0 to 74 (A1FI). We also simulate the hourly future climate for the 2040s and 2090s, for the A1FI scenario, to enable calculations of the potential available time for snowmaking in these two future time periods. We use simulated temperatures and humidity to calculate the total potential snowmaking hours in the future climates. For the snowmaking analysis, only a worst-case year in each time period, rather than an average year, was used to assess the snowmaking potential. This was done to ensure consistency with snowmaking design practices. At all sites, for the A1FI emissions scenario and for both future time periods, a reduction in potential snowmaking hours is observed. By the 2040s, there is only 82 to 53 %, and by the 2090s, there is only 59 to 17 % of the snowmaking time as compared to the 1990s in a worst-case year. Despite this reduction in snowmaking opportunity, snowmaking was still possible at all sites examined. Furthermore, the amount of snow which could be made was sufficient to reinstate the number of snow-days to the lesser of either that observed in the 1990s for each site or to exceed 100 days. While our snowmaking analysis has some limitations, such as neglecting calculation of melt in the man-made snow component, this study highlights the importance of considering adaptation options such as snowmaking for a more complete impact assessment.