Light pollution: environmental and health impacts at high latitudes.

Energy-efficient lighting solutions, while beneficial for reducing energy consumption, also pose challenges in terms of light pollution. Light pollution, defined as excessive or misdirected artificial light, has become a significant environmental issue globally. This perspective paper explores the extent, effects, and knowledge gaps related to light pollution, with a focus on its impact on human health, ecosystems, and energy consumption. This study focuses on Norway, a country that is particularly relevant for studying light pollution due to its far northern location. At high latitudes, the variation in natural light is larger over the year than at lower latitudes. Therefore, a Nordic perspective is valuable to present knowledge about effects of artificial lighting under these conditions. Under the midnight sun, minimal additional outdoor lighting is required, whereas during the winter season, outdoor lighting may be utilised continuously. The paper synthesizes findings from various studies, highlighting the rapid increase in light pollution due to urbanisation, infrastructure development, and the widespread adoption of LED technology. Human health effects include alterations of circadian rhythms, increased risk of accidents, and potential links to serious diseases such as cancer. Ecosystem impacts are profound, affecting a number of species i.e., within insects and bats, and may lead to for instance disturbances in navigation and circadian rhythms, habitat fragmentation, and altered predator-prey dynamics. This article identifies significant knowledge gaps, particularly in the measurement of light pollution, understanding its health effects, and its impact on various species. Recommendations for future research and policy development are provided, emphasising the need for interdisciplinary approaches to mitigate the adverse effects of light pollution and promote sustainable lighting practices.