How much light is too much?
In 2017, the gene that controls the circadian rhythm was isolated in all species, from bacteria to humans.
Our internal clock.
Yes, that of food and sleep; in fact, all our cells are organized on the basis of these natural cycles.
Night and day, light and darkness.
Our planet shines 24 hours a day. The Earth is a glowing ball of artificial light. Between 2011 and 2022, light pollution on Earth increased by 9.6% annually. The entire planet is in permanent jet-lag.
And what are the consequences?
The excess artificial light we live in has increased insomnia, depression and even obesity: the hormone that controls appetite, leptin, works in conjunction with melatonin, the hormone sensitive to light that induces us to sleep.
We sleep less.
Yes, and this disrupts our circadian rhythms, affects our hormone cycles and immune system. Melatonin is activated in the dark, our heart rate slows down, our body temperature drops, and from here many other processes necessary for our body are set in motion.
Ours and that of all living beings.
Yes, the same goes for the rest of the animals and plants. In addition, those with nocturnal habits are displaced from the dark conditions in which they have evolved and in which they socialize, feed and reproduce.
We have driven out the inhabitants of the night with our light.
In Switzerland they have investigated moths and meadows at night. Because of the lighting the moths cannot do their work and pollination has dropped by 60%, and this affects all ecosystems and the entire planet.
In China, trees are pollinated by humans.
Yes, I saw the pictures: In Sichuan province, several thousand workers climbed trees to pollinate flowers, doing the work that bees would have done.
But they don’t have bees anymore.
An efficient worker is able to pollinate ten trees a day; a small colony of bees pollinates a hundred times that number.
…
Light pollution is one of the main causes of the insect apocalypse we are experiencing. In some places, their populations have declined by 70% in three decades.
Half of the insect species are nocturnal.
They are guided by the stars and the moon, the brightest source of natural light in the night sky, until they meet the artificial light.
They squirm and die of exhaustion.
Even those that survive haven’t gotten their nectar and transported pollen from plants, haven’t found a mate, and haven’t laid eggs.
It’s a sad ending.
Newborn sea turtles head for land instead of the moonlit sea. Tricked by outdoor lighting, urban trees stay green longer than their rural counterparts.
Better in half light.
If we restore circadian rhythms in all animals and plants, we will have healthier ecosystems. In the streets we can put movement sensors and timers so that the lights turn off if they are not needed.
This is being a city that thinks.
Less harmful light sources, such as red or yellow light, can also be used. There are many things that can be done without having to turn off the lights completely.
That would change even us.
Yes, we could see some stars, something unusual in cities. We believe that light makes a place safer, but studies show that crime has nothing to do with a bright or dark city.
And no one dims the light?
In some places measures are already being taken. France adopted a national policy that imposes curfews on outdoor lighting.
And dark sky tourism wins.
Countries around the world that have regions less polluted by city lights offer stargazing walks or excursions to see the aurora borealis.
Desire for starry sky.
There is something about the feeling of being small under the night sky that fascinates us all.
And how do we return the animals to their night?
We need to have some places with total darkness and use dark corridors and nature reserves for the well-being of animals and plants.
