Climate change and declining snow cover may have health and energy use implications
Snow brightens the built environment both day and night in ways that may affect human health and energy use. Working together on the interdisciplinary project NorDark, Seren Dincel, a doctoral candidate at the KTH School of Architecture, and Arne Lowden, Associate Professor at the Stress Research Institute at Stockholm University, recently published two studies conducted in Uppsala. Together, the studies demonstrate how snow can support the regulation of human circadian rhythms and contribute to potential energy savings in public lighting systems.
The first study investigated the potential effects of snow cover on human biology and behavior in an urban population between December and February. Forty-five individuals were monitored for one week with snow cover and another week without snow cover using actigraphy*, diaries, and morning saliva samples to measure melatonin levels. The findings indicate that participants struggled to obtain adequate natural light exposure during December and January. Snow cover increased morning light exposure, lowered melatonin levels, and enhanced alertness and activity throughout the day. However, snow cover had minimal influence on sleep-wake cycles, sleep quality, and daytime mood ratings.
The second exploratory study investigated how the reflective properties of snow cover influence pedestrian pathway illumination. The research combined photometric measurements with questionnaires completed by residents. The study’s findings indicate that snow-covered environments substantially increase light levels, allowing reduced public lighting to achieve illumination comparable to that measured under fully illuminated conditions without snow cover. Increased snow depth correlated with higher reflectance, which increased light levels by nearly fourfold under the study conditions.
“With snowy winters projected to decline as the climate changes, there may be implications for urban planning, particularly with regard to public health and energy use in public lighting systems. Both studies explore relatively understudied topics: snow’s effects on the biology of urban residents and its relevance for adaptive dimming of public lighting in pedestrian settings. In after-dark environments, this may require different considerations for human (visibility) and more-than-human (ecological light pollution) dimensions,” says Seren Dincel.
Seren Dincel and Arne Lowden will present this work in a joint format under the title “Glowing albedo’s multifaceted effects on the environment, energy, and human health” at the Light Symposium Copenhagen in September 2026.
* Actigraphy is a method of monitoring human rest and activity cycles using a small, wristwatch-like device equipped with an accelerometer that tracks movement, wakefulness, and sleep patterns.
Both studies are published in academic journals:
- Lowden, A. & Dincel, S. (2025). The Snowball Effect : Snow cover increases light exposure, suppresses melatonin, and improves alertness in an urban population at northern latitudes . Chronobiology International, 42(12), 1699-1710.
- Dincel, S. & Lowden, A. (2026). Illuminated by snowglow : Interplay of pedestrian path lighting with materiality in peri-urban green space. City and Environment Interactions , 29.
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