Submitted to City of Lethbridge, Community Safety Standing Policy Committee
The Southern Alberta Group for the Environment (SAGE) supports the initiative being advanced by Rena Woss regarding the development of a Light Nuisance Bylaw for Lethbridge.
Light that trespasses into personal living spaces, including backyards, has negative impacts both to human wellbeing and the environment. The Leadership in Energy and Environmental Design (LEED) organization identifies light as a form of pollution affecting people and the environment and as a potential source of energy-waste (with related greenhouse gas emissions). They recommend that external lighting be used only when and where they are required. And if external lighting is necessary that it is shielded from evading to the outside of the property.
The LEED goal is stated: “To minimize light trespass from the building and site, reduce sky-glow to increase night sky access, improve nighttime visibility through glare reduction and reduce development impact from lighting on nocturnal environments.” They identify four maximum levels of illumination depending on location: parks (LZ1); low density urban areas and light commercial and industrial areas (LZ2); higher density residential and commercial areas (LZ3 & 4). Each category sets strict design limits for horizontal and vertical lux. The LEED goal clearly articulates privacy, aesthetic, safety, and environmental reasons to reduce, regulate and better manage external lighting. With respect to the Municipal Development Plan, a future City of Lethbridge Climate Adaptation Plan might establish this type of zoning and design expectations for reducing light pollution in the urban environment.
It is important that the City of Lethbridge adopt a bylaw that not only protects the wellbeing and privacy of individuals from light trespass but preserves biodiversity in the urban and peri-urban areas from the impacts of lighting on nocturnal environments. Plants and animals depend on the daily rhythm of light and dark to govern life-sustaining behaviors such as reproduction, nourishment, sleep and protection from predators. Artificial light disrupts these rhythms, leading to biodiversity loss including many of the insects that we rely on for pollination and other ecosystem services.
Considering the growing awareness of the profound impacts of greenhouse gas emissions on the stability of our climate, wasting energy for aesthetic or perceived security goals should be strongly discouraged. Though reduction is the primary goal, properly designed lighting can achieve the lighting goals and reduce wasted light (and energy) by as much as 35% (https://www.darksky.org/light-pollution/energy-waste/). A cursory tour of Lethbridge at night should suggest that this sort of reduction would not be inconsequential.
In summary, SAGE supports the initiative for the development of a light nuisance bylaw that not only protects the well-being of individuals but also reduces unnecessary and wasted external lighting through better design and public awareness. It is important to preserve the nocturnal environment and reduce greenhouse gas emissions.