Light pollution is the excessive light produced by humans at night. This light comes from artificial sources, mainly electricity form streetlamps, billboards, houses, offices and even car headlights. There are two kinds of light pollution: point source, which means that the light is produced directly from a source, and skyglow, the accumulated effect of point source lighting that eventually spreads through the earth's atmosphere. This is a slight glow that we see on the horizon if we look towards a city from a rural place.
Studies show that a quarter of the earth's global land area is said to be under light polluted skies, 80% of the world's population now live under light polluted skies and they are not even aware of it. It means that a third of all the people in the world can no longer see the Milky Way.
Artificial light at night was invested because at one point in time, the earth was in utter darkness. We only experience sunlight daily because of the earth's rotation and it being close to a star. We adapted to the constant and regular day-night cycles.
The problem with light pollution is that it affects the environment in a way that it disrupts the natural light cycles that species are wired into. These include changes in time partitioning. Light pollution also has a negative effect on human health. Melatonin is the hormone that regulates our sleep patterns and it is expressed under the light. The changes in light caused by light pollution means that it becomes vital to the hormone's natural expression. This is said the be linked to reduced sleep, obesity and impaired memory.
Melatonin is an antioxidant that can remove free radicals, so this means that the disruption of its expression may increase cancer risk. Researchers are now spreading the five key strategies that they've outlined to help reduce lighting globally without compromising its benefits.
Dark areas should not be introduced to light, lighting should be at the lowest intensity that is possible but still usable, lighting should be used where its directly needed, lighting should only be used when it is required and lighting should have more orange colors instead of the white spectrum.
Light pollution is increasing and while many people from the rural areas can still see the Milky Way, the expansion of infrastructure with lighting is imminent. Researchers are still finding ways on how to ensure that the economic trajectory does not compromise environmental and human health.