DW: How by turning off the lights in cities, Germany is protecting the climate and human health

The energy crisis has prompted cities across Germany to switch off the night lights at many landmarks and buildings such as town halls, museums and libraries.

As Deutsche Welle Berlin reports, 200 landmarks, including the Victory Column and the city’s Cathedral, will be left in the dark when the sun goes down.

As of September 1st, the energy saving decree officially prohibits the external lighting of public buildings. Meanwhile, neon signs may only work for a few hours a day.
Meanwhile, the city of Weimar in central Germany is saving energy by turning off its street lights for an extra hour each day.

But beyond saving energy and money, “dark” cities have many positives for both the climate and our ecosystem.

Closed lights help combat air pollution

The International Dark Sky Association, an Arizona-based NGO, estimates that about a third of all outdoor lighting is used at night without benefit. Even before the energy crisis and higher prices, stopping this fruitless lighting would save $3 billion (€2.9 billion) a year.

Since fossil fuels are still the main source of energy worldwide, turning off these unnecessary lights helps reduce air pollution and harmful emissions.

In India, for example, extreme city lighting emits 12 million tons of CO2 annually, according to Pavan Kumar of the Rhani Lakshmi Bai Central Agricultural University in Uttar Pradesh state.

This is about half of the country’s total air and sea pollution annually.

Today, more than 80% of people worldwide live under light-polluted skies. In Europe and the US, the figure reaches 99%, which means that people no longer experience true darkness.

In Singapore, for example, the nights have become so bright that people’s eyes have difficulty adjusting to real darkness.

Why do we need darkness?

Sufficient darkness at night is also good for health. Studies have shown the link between artificial light and eye injury, insomnia, obesity and in some cases depression.

A lot has to do with melatonin, a hormone that is released when it gets dark.

“When we don’t get that hormone, when we don’t make that hormone because we’re exposed to so much light in our apartment or as a shift worker, then the whole function of that biological clock system becomes problematic.” said Christopher Kimba, a scientist at the Potsdam-based German Research Center for Geosciences.

A 2020 study from the US shows that children and teenagers who live in areas with a lot of artificial light sleep less and suffer more often from emotional problems.

The introduction of artificial light is “one of the most dramatic changes we’ve made to the biosphere,” Kyba said.
Scientists estimate that our planet is getting 2% brighter every year.

Thus, reducing or partially switching off street lights could be a first step in tackling light pollution. This is despite theories that darkness affects accident or crime rates, a hypothesis contradicted by a study in England and Wales.

Animals and plants also like the dark

Wildlife also find it difficult to adapt to the use of artificial light at night. Corals, for example, are not reproducing as usual, migratory birds can lose their sense of direction and newly hatched turtles have been found walking inland, where they die.

In fact, insects are also affected. A study shows that around 100 billion nocturnal insects die every summer in Germany as a result of artificial light. They usually depend on the moon for orientation, but they are so distracted by bright street lights, for example, that they fly around all night. They then die of exhaustion, are too weak to reproduce, or become easy prey for predators.

Several recent studies have shown that plants growing near street lights are fertilized much less often at night and produce fewer fruits. Even the trees feel the effect.

DW – Tim Schauenberg

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