The Light pollution it is a growing problem. That’s clear. But perhaps it was not entirely clear how growing it is. To see it, you just have to see the report on the matter that the Sky Quality Office of the Institute of Astrophysics of Andalusia (IAA).
It shows the results of the analysis of the situation between the years 1992 and 2017. A total of 25 years, in which it can be clearly seen how negatively the entry on the scene of the led lights.
In fact, it is concluded that in that period light pollution has increased at least 49%. But it is a very optimistic estimate, as it could actually rise globally up to 270%. With 400% in some areas. It is clear that it is a problem that must be tackled.
What is light pollution?
Light pollution is complex to describe, as it depends on many factors. Broadly speaking, it can be said that it is the introduction of artificial light in an inherently dark environment such as open spaces at night. But, with this definition, it could be concluded that any light pollutes.
Therefore, it is specified that it is artificial light with unnecessary intensities, directions, times and spectral ranges. In short, a very intense light, very blue or on in a place with little traffic, at an hour when no one passes.
But what does color have to do with all this? It has been proven that it is the light with a greater blue component that pollutes the most. That is, the one that most hinders sky observation. Furthermore, it is precisely this light that most affects ecosystems, including the health of human beings themselves.
Photo by Guthrie Kuckes on Unsplash
Little known issues
If we ask someone for the Light pollution, you may know that it is the reason why too much lighting prevents us from seeing the sky. This is a problem, both for astronomers, who cannot carry out their work correctly, and for us, who cannot enjoy the wonderful spectacle that the night sky.
Insects, sea turtles and birds are some of the animals affected by light pollution
A good example of this was something that happened during an earthquake in The Angels in the 90s. It is said that, after the blackout caused by the earthquake, emergency telephones received a multitude of calls from citizens scared by the appearance of a huge silver stripe in the sky. As if the sky were suddenly torn apart. Actually, nothing strange had happened. Merely, lacking the enlightenment of the city, they were watching the Milky Way. A spectacle that had always been above their heads was seen majestic, for some for the first time, suddenly showing how sad the Light pollution.
But it is also harmful. For example, it affects insects very dangerously. We have all ever seen a cloud of mosquitoes flying swirling around a lamppost. This is because these animals have sensors that help them locate the light from the moon and the stars, in order to orient yourself. The problem is that they can mistake artificial light for these stars, so they fly until they run into it directly. This can lead to charred death, but it can also lead them to stay there, flying in a daze until they fall exhausted. The problem is that while the insects are concentrated there, they cannot perform such important functions as the pollination. And they are also not available to the animals that feed on them. Therefore, it is not only the insects that suffer, but also many other components of the ecosystems.
In addition, it has been seen that light pollution directly affects other species, such as birds, which can end up colliding with buildings when they are dazzled by light. Waves sea turtles, who are having more and more trouble finding dark beaches to lay their eggs on. It is something very problematic, because when the little turtles are born they are guided by the Moon and the stars to reach the sea. However, if streetlights are placed in the opposite direction, they will possibly walk towards them, confused, and will end up losing the sea and entering the cities, with the dangers that this entails.
We cannot forget the problems posed by the blue light for human beings. It is known to be involved in the regulation of melatonin release, a hormone very involved in the correct development of circadian rhythms, as it helps to trigger sleep. An excess of blue light inhibits the release of melatonin, so exposure to it at night leads to trouble sleeping. In addition, its relationship with some types of cancer, such as prostate or breast.
What can be done to combat light pollution?
There are solutions to combat light pollution, most of them related to the correct placement of luminaires. It is not about living in the dark, but about using those that least damage the sky, ecosystems and ourselves.
The spectral index G is a very important measure to calculate how blue a light is
For example, it is important that the streetlights do not direct the light upwardsbut towards the ground. They can also be regulate schedules, so that they are turned off in areas with less traffic. In addition, the latter can go one point further with the use of sensors that detect when a person, a car or even an animal passes. Thus, they would turn on to illuminate you and would turn off again, so that they only exert their function when it is really necessary.
And of course it is important to select the most suitable light. For this, you can use measures such as spectral index G, developed by the astronomer David Galadí, of the Calar Alto Observatory. It is a calculation that allows the spectral characteristics of a light source to be quantitatively determined. Said very briefly, it gives us a numerical value that indicates how blue a light is. It is a very important piece of information, which is helping a lot in the fight against light pollution, as it helps to select the best luminaires.
Unfortunately, no matter how much effort the experts are putting in, it is also important that the competent authorities do their part to legislate according to what the science indicates in this regard. For this reason, numerous scientific groups, such as the Spanish Society of Astronomy, have shown their disagreement with the draft reform of the Royal Decree 1890/2008, which regulates outdoor lighting, “since although on paper it provides for the reduction of light pollution, it could have just the opposite effect.” Scientists warn that it has “excessive permissiveness” and that it will encourage sky pollution by using excessive maximum illumination values and enhancing the illumination of “huge areas”. In addition, it promotes the use of a very blue light.
For this reason, the Institute of Astrophysics of Andalusia has now published its report, since it is this week when the term for allegations to this reform ends. And the conclusions seem clear. When analyzing satellite data taken in 25 years, it is concluded that throughout that time light pollution increased at least 49%. However, satellite sensors are blind to the blue light, so they underestimate emissions, which could be much higher. In fact, when also observing the images taken from the International Space Station, a clear deterioration is observed, closely related to the rise of LED bulbs. So much so that the increase could be 270% globally, and up to 400% in some regions.
Heaven is also our heritage. Lately we begin to worry more about the planet than we will leave our children and grandchildren. We should also go a little further and think about how we leave the sky for them. It would be very sad for a day to come when you look up and, as happened in Los Angeles, think that your sky has been broken.