Arctic winters are getting warmer, leading to more shrubs growing in the tundra. This change is likely due to snow-covered shrubs trapping heat, insulating the ground, and supporting cold-resistant microbes. The deeper snow caused by more shrubs increases soil temperatures, boosts microbial activity, and adds nitrogen to the soil, which helps shrubs grow better in the summer. As the climate continues to warm, large areas of tundra could turn into shrubland, with winter processes playing a crucial role in this transformation.