Snow plays a crucial role in shaping near-ground and soil microclimates at high altitudes and latitudes. A thick snowpack effectively insulates the ground from atmospheric fluctuations but can significantly shorten the growing season in areas with substantial snow accumulation. Alpine and polar regions, characterized by variable terrain, exhibit heterogeneous snow cover depth and duration. This spatial heterogeneity suggests that local manifestations of climate warming may differ depending on snow conditions and their evolution over time.

Here, I present preliminary results from a two-part investigation. First, I analyse a multi-year microclimate logger timeseries from nearly 800 measurement locations in Finland, Norway and Sweden to quantify the interannual variation in microclimates attributable to varying snow conditions. Second, I utilize downscaled climate reanalysis data with remotely-sensed annual estimates of local snow cover duration across 600 alpine and polar regions to determine where and to what extent snow limits the growing season length and potential thermal sums.

Overall, I provide both theoretical and empirical insights into how snow modulates local climate warming rates in alpine and polar environments both during winter and summer. These findings highlight the potential for highly heterogeneous microclimatic responses to climate change, not only across regions but also within landscapes of snowy ecosystems. Consequently, snow conditions may introduce significant uncertainty into predictions of future biodiversity and ecosystem productivity in mountainous and polar regions.