Light pollution and its mitigation are not unidimensional issues, they encompass a wide range of interrelated factors that impact various aspects of human life and the environment. Approaching lighting, its effects, and regulation from multiple perspectives—social, ecological, and technical – was discussed during our recent event at the University of Brest - Université de Bretagne Occidentale (UBO).
Adopting a round table format, the event welcomed about 30 attendees, mostly students along with a few external guests. This collaborative event was made possible through the joint efforts of the DARKER SKY team at UBO and students from the Master's programme Management and Conservation of Biodiversity . Our aim was clear: to discuss the issue of light pollution from three distinct angles – technical, ecological, and social, thanks to the diverse expertise of our three speakers.
Our speakers were:
Saïg Potard - technical expert in public lighting from the municipality Brest Métropole, who focusses on the operational aspects of managing light pollution in urban settings (DARKER SKY project partner).
Yoann Roulet - ecologist from the Laboratoire Géoarchitecture, Territoiries, Urbanisation, Biodiversité, Environnement, highlighted the impacts of excessive artificial light on biodiversity (DARKER SKY project partner).
Nina Rouzée - social psychologist, provided insights into how the general public perceives the night, based on a sociological study she carried out in one of Brest's neighbourhoods in the autumn/winter of 2022-2023 as part of the university chair "Chaire Noz Breizh".
Technical perspective
During the talk, it was noted that light pollution has gradually gained attention and been increasingly recognized as an important issue. In France, the first important step was taken with the decree of 27th December 2018, which gave clear instructions on when lights should be turned off in public as well as in private places. Now, the question of lighting is obligatory in the urbanisation of French cities, which have to include, for example, a Dark Framework ("trame noire") in the Local Town Planning Scheme ("Plan Local d'Urbanisme / PLU").
From a technical standpoint, lighting design and implementation involve considerations such as energy efficiency, light intensity, spectral composition, and directional control. Properly designed lighting can minimize light pollution while providing adequate illumination for safety and visibility. Technical expertise is crucial for developing innovative lighting solutions that balance functionality with environmental sustainability.
As a public administration, it is very important for Brest Métropole to think about the usefulness of lighting. Since 2016, Brest has focused on the usefulness and efficiency of lighting, transitioning to LED lights for increased power and energy savings. As a result, overall lighting usage has decreased, with maintenance ensuring lights are never as bright or on for as long as before.
Light modifications at Brest’s demonstrator sites
Photo: Pierre-François Watras/Brest métropole
Moulin Blanc beach:
Complete renovation of the lighting, decrease in support height, change of color temperature, lanterns, operating profile (dimming depending of hours in the night), removal of existing poles, bicycle counting and partial switch-off of public lighting
Saint-Anne du Portzic:
The colour temperature of the lights will be changed and luminaires will be renovated with light breaks. More specifically, on the main road, the lights will be switched off between 22:30 and 6:00, and in the pedestrian zone next to the beach, the lights will be either switched off or simply dimmed thanks to a detector
Learn more about our demonstrator sites here.
Ecological perspective
Yoann Roulet highlighted the impact of light pollution on biodiversity. Artificial light at night can interfere with the circadian rhythms of animals, affect migration patterns, and disrupt reproductive cycles. By considering the ecological impacts of lighting, conservation efforts can be integrated into urban planning and lighting design to protect biodiversity and maintain healthy ecosystems. Yoann is part of the DARKER SKY team. In the project he develops common biodiversity assessment protocols across the project's demonstrator sites to investigate whether the light modifications installed at the demo sites impact the local and migratory species (diurnal and nocturnal, terrestrial and marine).
Social perspective
Lighting has profound effects on human behaviour, well-being, and perception of space. It influences how we interact with our surroundings, shapes our sense of safety and security, and even affects our health and quality of life. Understanding social dynamics related to lighting helps policymakers and urban planners create lighting solutions that meet the needs and preferences of communities while minimizing negative impacts.
The round table discussions unveiled the association between nighttime lighting and perceptions of security, despite evidence suggesting otherwise. While there's growing interest in the topic of light pollution, there's still much to be done in terms of public awareness. Many are familiar with the term but lack a comprehensive understanding of its implications, including health, safety, energy consumption, and biodiversity.
In the DARKER SKY project, we conduct assessments of all demonstrator sites which includes sociological aspects as well. We aim to investigate and integrate stakeholder needs (identification of end-users, establishment of regional stakeholder groups, applying legal, technical and security standards).
In conclusion, our event emphasized the need for continued efforts to raise awareness and foster interdisciplinary dialogue about light pollution. By integrating insights from social, ecological, and technical perspectives DARKER SKY aims to support policymakers, urban planners, and lighting professionals to develop holistic approaches to address light pollution effectively. This multidimensional approach ensures that lighting solutions not only meet practical needs but also promote environmental stewardship, enhance quality of life, and support sustainable development goals.
Photos: Enora Morin