French stargazing festival raises awareness of light pollution threat

The ‘Nuits des Étoiles’ events run from August 11 to 13 - an expert tells us why we must protect our night skies for biodiversity

View from the Pic du Midi Observatory in France’s first International Dark Sky Reserve
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Warm summer nights are the ideal time for stargazing in France, with the annual Nuits des Étoiles festival set to take place from August 11 to 13.

The stars might even be more visible this year, as there is a growing awareness of light pollution as a threat both to our night skies and to biodiversity.

The government recently announced it would launch a public consultation into reducing public energy bills and light pollution. Energy Minister Agnès Pannier-Runacher cited the latter’s “devastating effect on biodiversity”.

People in France will be able to say if they think street lighting should be lowered or turned off overnight, and whether the obligation for shops to turn off their lights from 01:00 to 06:00 is sufficiently strict.

Read more: French towns introduce ‘smart’ street lights which locals can turn on

France’s first Dark Sky Reserve

The existence of a national debate is a sign of how much progress has been made since France’s first International Dark Sky Reserve was created at the Pic du Midi (Hautes-Pyrénées) a decade ago.

But there is still a lot of work to do, says Nicolas Bourgeois, deputy director of the site.

“Ten years ago, at best we were seen as inoffensive scientists, or even poets,” he said. That changed with the Dark Sky Reserve label, which has allowed the department to raise millions of euros to transform its street lighting.

The certification was created by the US-based International Dark-Sky Association (IDA), and is awarded based on sky quality and steps taken in the surrounding area to support dark sky preservation.

Three more French sites have since obtained the title: the Mercantour and Cévennes national parks, and the Millevaches regional park in Limousin.

‘Like putting skyscrapers next to a magnificent coastline’

Mr Bourgeois has a PhD in geography and was heavily involved in applying for the certification for the Pic du Midi: 246 communes have committed to reducing light pollution in the area surrounding the Pic du Midi Observatory.

“In an area where tourism is an important part of the economy, we were able to convince local actors of the need to protect nighttime landscapes,” he said.

“We warned people that these magnificent mountain landscapes with the Milky Way above them were threatened by light pollution.

“It’s as if you had a magnificent coastline and put skyscrapers right next to it.”

Light pollution impacts nocturnal animals

Recent studies have also highlighted the negative effects of light pollution on biodiversity, from bats to caterpillars.

A third of vertebrates and two-thirds of invertebrates are nocturnal, and for them night is essential for hunting, reproduction and migration.

“The night is a habitat like any other. When lighting is poorly designed, that habitat is damaged,” Mr Bourgeois said.

The Pyrénées national park worked with the local syndicat d’énergie to identify areas where the wildlife is particularly sensitive to light pollution and to adapt the lighting accordingly.

Solutions include using warmer colours, and lamps that only light the intended area, meaning their power can be reduced.

Several other areas, including Lille, have begun implementing their own trame noire (black thread), aiming to reduce light pollution in key areas.

“Originally, lighting was very symbolic of modernity. The spherical street lights we used to have would shine on everything except what people needed to see.”

2018 street light law put France ahead

A December 27, 2018, decree banned street lamps that release light directly into the sky, as well as other measures including a ban on lamps shining directly above rivers and lakes, policies that “position France ahead of all but a handful of nations in terms of their comprehensive nature”, the IDA said at the time.

Mr Bourgeois says that the greater challenge has been to change mentalities rather than develop new technology, but he believes tackling light pollution can be a rewarding way to get people to care about the environment.

“When you turn the lights off, the night comes back immediately. It’s as if the Amazonian rainforest instantly started growing back.”

500 events across France for ‘Nuits des Étoiles’

Saving money has also been an effective motivator, as an increasing number of towns and villages have decided to turn off their lights for part or all of the night in response to the energy crisis.

Read more: Lyon restaurants turn out the lights to protest soaring energy bills

In some areas, Mr Bourgeois said, this has resulted in “a quality of sky we couldn’t have imagined since the middle of the 20th century.”

However, he warned, those communes must also focus on using better lighting technology.

First, because biodiversity is mainly active in the first part of the night, so species can be harmed even if the lights go off at midnight.

Secondly, in case energy prices were to fall in the future and the lights came back on.

In the meantime, dark sky reserves such as the Pic du Midi face another hurdle: the lack of an official status in French law.

In September, representatives of the four sites will come together for a first national convention, with the goal of developing proposals for their future framework.

More than 500 events will take place this month for the Nuits des Étoiles, organised by clubs, planetariums and town halls. Find those near you.

Look out for..

The Perseids meteor shower, which can be seen every August, has begun and will be visible until August 24, peaking around August 12-13. It can deliver up to 100 shooting stars per hour at its height

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