According to new research and article recently posted by National Geographic, 83% of the global population lives under light-polluted skies. In the USA and Europe, this number is even more drastic were almost 90% of the population is impacted by light pollution.

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Even though the bulb is one of the greatest inventions in human history, it has its dark side as well. It can negatively impact our health or even whole ecosystems.

What is light pollution?

Light pollution is the artificial light visible in dark conditions. It is created by excessive usage of lights and it is a negative side effect of urbanization. The biggest light pollution “producers” are big cities full of artificial lights that are lighting up the night sky. The majority of light pollution comes from the East part of the USA, Europe, China, Japan, India, and the Middle East.

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Manhattan from the space. Photo by NASA.

Light pollution is also created by satellites that are reflecting the sunlight back to Earth.

The awareness about light pollution was firstly raised in the second half of the 20th century. In 1988 the International Dark-Sky Association (IDA) was found to combat this problem.

Too much light pollution can have a negative impact on our health. It can also disrupt whole ecosystems and the environment.

Light pollution map.

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What are the negative effects of light pollution?

Energy problem.

The first problem of light pollution is the energy problem. The more bulbs and lights we use the more energy we need to power them. And if the equipment is not efficient enough the unwanted illumination can get higher.

As an example just take look at the light pollution created by one single light. If the light is too strong the unwanted illumination is also very high. That’s why many urban architects are nowadays trying to swap them for more eco friendly LED lights in their projects.

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Also, we can see a huge change in society where people are voluntarily exchanging the old halogen bulbs for LEDs. In Europe this is mandatory as the halogen bulbs are banned in the whole European Union and they can’t be sold in the stores anymore.

Human health problems.

Light pollution is one of the biggest often underrated cause of medical problems. Too much exposure to artificial lights can cause headaches, decrease sexual life, or increase anxiety.

In 2007 the International Agency for Research on Cancer (IARC) which works under the World Health Organisation (WHO) published a study that shift work can cause cancer. This is due to a huge exposure to artificial lights during the night, which is unnatural to humans.

According to another study, too much light pollution from artificial lights in the evening can cause sleep disruption. And if you think that to dim your lights or the devices is enough to improve your sleep you are wrong.

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Impact on the environment.

The negative effect of light pollution on the environment is called ecological light pollution. The artificial light mainly impacts nocturnal animals and plants, but it can be also disruptive to migrating birds.

It confuses the orientation of animals and causes physiological harm. Some species that are depending on dark conditions can be unable to reproduce when extremely exposed to light pollution.

This issue not only affects the animals or plants itself bu in the long-term it can destroy the whole ecosystem.

Light pollution – negative impact on health and the environment.
The glare of Paris is visible from many kilometers.
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Light pollution above Los Angeles.

Light pollution and its impact on astronomy.

Light pollution is not only created on Earth. In some parts, it is also coming from space where it is created by satellites. The satellites reflect the sunlight back to the Earth making the sky observations very difficult.

This problem will only grow in as the number of satellites in the orbit will increase in the upcoming years.

Elon Musk just submitted new paperwork for 30 000 additional satellites for his Starlink project. Once this will be approved and the project finished it will create the biggest constellation consisting of 42 000 satellites.

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The night sky before and after the blackout in Toronto. Photo by Todd Carlson.


There is no way that we could switch off all the lights forever. The lights during the night also have their benefits. Like illuminating the roads, crosswalks, pedestrians and our homes.

But there are few solutions that can lower their negative impact. The first one is to always switch off the unnecessary lights and to use low energy LED lights.

Another solution is to make sure that whatever urbanization project comes next its creators will have the light pollution in mind. I guess that fixing this issue will take some time, but it is definitely worth trying.

And if you feel helping just a bit more, you can join these years Eart Hour on the 28th of March.

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