Germany must accept leading military role: Defense ministerBerlin, Sep 12: The energy crisis has inspired cities across Germany to turn off night lights at landmarks, monuments and prominent buildings such as city halls, museums and libraries.
In Berlin, 200 landmarks including the Victory Column and the Berlin Cathedral are to remain unlit when the sun goes down.
Since September 1, the Energy Saving Ordinance has also officially prohibited the illumination of public buildings from the outside. Meanwhile, neon signs may only burn for a few hours a day.
The city of Weimar in central Germany is saving energy by shutting off the street lights for an hour longer each day.
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But beyond saving power and money, darker cities have numerous positives both for the climate and biodiversity.
The International Dark Sky Association, an Arizona-based NGO, estimates that about one-third of all outdoor lighting burns at night without benefit. Even before the energy crisis and higher prices, shutting off this fruitless lighting would save $3 billion (€2.9 billion) a year.
Since fossil fuels are still the main source of energy worldwide, simply switching off useless lights helps reduce air pollution and harmful emissions.
In India, for example, extreme lighting emits 12 million tons of CO2 per year, according to Pavan Kumar of the Rhani Lakshmi Bai Central Agricultural University in the state of Uttar Pradesh.
That's about half as much as the country's total air and sea traffic per year.
Today, more than 80% of people worldwide live under light-polluted skies. In Europe and the US, the figure is as high as 99%, meaning people no longer experience real darkness.
In Singapore, for example, nights have become so bright that people's eyes now struggle to adapt to real darkness.
Sufficient darkness at night is also good for health. Studies have demonstrated the link between artificial light and eye injury, sleeplessness, obesity and in some cases depression.
Much is related to melatonin, a hormone that is released when it gets dark.
"When we don't get that hormone, when we don't produce that hormone because we're exposed to so much light in our apartment, or as a shift worker, then the whole working of this biological clock system becomes problematic," said Christopher Kyba, a scientist at the Potsdam-based German Research Center for Geosciences.
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A 2020 study from the US shows that children and adolescents who live in areas with a lot of artificial light get less sleep 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," said Kyba.
Throughout evolution "there was a constant signal coming from the environment," he explains. "This is daytime, this is nighttime, this is the lunar month. In areas that experience strong light pollution, that signal has been dramatically changed."
Scientists estimate our planet is becoming 2% brighter every year.
So dimming or partially turning off street lights could be a first step in counteracting light pollution. This is despite regulations that deem darkness influences accident or crime rates, an assumption contradicted by one study in England and Wales.
Wildlife also struggles to adapt to the use of artificial light at night. Corals, for example, don't reproduce as usual, migratory birds can lose their sense of orientation, and, rather than walking toward the sea, newly hatched turtles have been found walking inland, where they die.
Insects are also affected. One study suggests that an estimated 100 billion nocturnal insects die in Germany each summer as a result of artificial light. Usually reliant on the moon for orientation, the critters become so distracted by bright streetlamps for example, that they fly around them all night. They then die from exhaustion, are too weak to reproduce or become easy prey for predators.
Several recent studies have showed that plants growing near streetlights are pollinated significantly less often at night and produce less fruit than their unlit counterparts. Even trees feel the impact of light at night, budding earlier and with later leaf fall than others.
Source: DW