Global reduction of snow cover in ski areas under climate change

compacting towards higher elevations, conflicts between skiing and alpine biodiversity are likely to increase with the reduction of skiable areas towards higher elevations. Despite this ubiquitous potential for space conflicts between nature conservation and downhill skiing, global assessments of snow cover conditions in ski areas under climate change is lacking. The economic recreational value of ski areas has raised interest in future projections of snow cover and snow duration in times of climate change. Regional studies assessing future snow reliability project decreasing snow cover days (scd), reduced ski season length and over- all reduced snow reliability particularly at low elevations [1, 6–10]. In the European Alps, a ‘Christmas-Easter shift’ will be likely as optimal ski days are predicted to shift towards the end of the ski season [11]. Generally, research investigating the effects of climate change on snow reliability is biased towards Europe, North America and Australia and is targeting mostly small-scale assessments. This reflects the economic importance of skiing, with the European Alps having the largest global ski market, followed by North America [12]. Technical improve- ments and management strategies, such as artificial snowmaking, are widely used to counter- act snow scarcity and to ensure economic success of ski areas, which is marked by the 100-day-rule [13]. However, artificial snowmaking will presumably not be a sufficient com- pensation measure under a severe climate change scenario [8]. Other adaptation strategies like

slope contouring, landscaping, the protection of glaciers on existing skiable terrain as well as the development of new ski areas at, for instance, north facing and higher elevated slopes [14] are in addition commonly considered as threats to nature and the unique mountainous biodi- versity [15]. Associated risks are likely to increase with changing snow availability due to cli- mate change. Besides the importance of high-elevation mountainous systems for the skiing sector, they also harbour a unique biodiversity, including numerous endemic and vulnerable species [16]. These systems are threatened by both climate change [5, 17] and by changes in tourism [18] as a response to climate change. Spatial conflicts between potential areas suitable for skiing and biodiversity conservation, especially of high-elevation species, can intensify with climate change. An uplifting of both, suitable habitats for species, as well as areas with sufficient snow availability for ski areas, is expected under ongoing climate change [16]. The spatial conflict will be exacerbated by the decline in available area towards higher elevated mountain areas. This effect potentially includes tendencies of ski areas expanding into less populated and yet naturally protected or less disturbed mountain areas at high elevations. Such a spatial focus of ski areas towards remote systems would most likely result in the expansion of infrastructure and thus habitat degradation as well as the loss of mountainous flora and fauna. Negative

effects of ski areas on nature are widely investigated and range from changes of soil properties due to grooming and snowing activities to habitat fragmentation [19–22]. Despite the global potential for an intensification of spatial conflicts between downhill ski- ing and nature conservation with global warming, studies targeting the assessment of the dis- tribution of future ski areas mostly focus on regional scales and some major mountain areas have not yet been considered. Such assessments have so far been limited by the lack of global- scale and fine-resolution projections of snow cover days (scd) as well as openly available geo- information on ski areas. Since data availability is rapidly growing, this study is the first to combine open-source information on global geo-locations of ski areas with openly available global snow cover day projections. Our approach enables assessing the global patterns of alter- ing ski area distributions by identifying future trends (2011–2100) in natural snow cover days for ski areas worldwide. We focus on seven major mountainous skiing regions, namely, Euro- pean Alps, Andes, Appalachian Mountains, Australian Alps, Japanese Alps, Southern Alps, and Rocky Mountains under the emissions scenarios SSP1-2.6, SSP3-7.0 and SSP5-8.5. Result- ing range contractions and the change in annual snow cover days of ski areas will be assessed. PLOS ONE Global reduction of snow cover in ski areas under climate change PLOS ONE | https://doi.org/10.1371/journal.pone.0299735 March 13, 2024 2 / 15 design, data collection and analysis, decision to

publish, or preparation of the manuscript. Competing interests: The authors have declared that no competing interests exist.