Light pollution: in search of lost darkness

In his Parisian offices, François Migeon, a lighting artist, is working with his team on an eco-district project in Pantin, near Paris.

The complex will alternate between new housing and green spaces, but there are also plans to set up a dark grid, a dark path to allow species to migrate between natural spaces.

"We realize that we don't necessarily have the same fauna and flora from one space to another. The more we connect them, the more we will enrich biodiversity. And the night is a good time to generate these movements," explains François Migeon.

Light pollution is beginning to be taken into account more and more, including in urban development projects.

"We now know that this pollution has the 'same effects' as concrete, that is to say that it will degrade habitats for species that are sensitive to night-time light and it will also create barriers," explains Romain Sordello, a specialist on the subject at the French Office for Biodiversity.

The expert describes to AFP a range of harmful effects: "Animals that navigate by the stars will tend to orient themselves towards artificial lights. They will be drawn into 'traps' where they will generally die of exhaustion, like insects."

At the other end of the spectrum, some animals - bats, amphibians, etc. - are repelled by light, which exposes them to predators.

To protect them, we therefore need corridors - these famous black frames - where darkness reigns. In the case of Pantin, François Migeon shows the map: a cemetery on one side, a large green space on the other, a little further the Parc de la Villette. The objective is to illuminate the city while creating a dark path between these places.

“Re-enchanting the night”

"When we do a project, we try to understand how the city works. Where is the station? Where are the attractions? Are there people who are going to go out late? This will create a sort of lighting program that will allow us to provide appropriate responses," explains the designer.

Several solutions can be implemented, between presence detection and lights extinguishing. Lighting designers are also working on innovations, such as a mobile phone that would allow the area crossed to be lit or portable lanterns to be rented on the model of Vélib.

An idea defended by Roger Narboni, who developed the concept of black grid in public lighting. "We should change software," argues the lighting designer from his Parisian apartment.

"Do we still systematically need public lighting? Can't we give people more autonomy? We can have sensors, presence detectors, we even have voice control. There is a phenomenal technological capacity today," he lists.

But the public authorities still need to follow suit. At the end of 2018, France adopted a decree on the prevention of light pollution, which notably sets the extinction of lighting at one o'clock in the morning for parks or shop windows. But the means of control remain limited.

Cities are also faced with the feeling of insecurity generated by the night, even if it does not necessarily encourage attacks. "We must nevertheless take this feeling into account," says Roger Narboni. "With differentiated routes, in the dark and in the light."

Although the road remains long, awareness is on the rise, according to the stakeholders interviewed by AFP.

"I don't imagine that we will move towards total darkness in the next ten years," concedes Mr. Narboni, "but I believe in an education in darkness: we must re-enchant the night." If only because this will, in any case, allow energy savings.