Artificial lights have revolutionized the way humans live their day-to-day lives. We’ve moved beyond the sun’s natural cycle and rely heavily on street lights, light bulb fixtures and flashlights. Unfortunately, we are now faced with what scientists call, “light pollution”. In big cities especially, the concept of “night” is almost obsolete because artificial lights are kept lit throughout the night. Now, more than ever, human and environmental health is suffering from this boom of artificial lighting. According to Bewitter, these are the various ways light pollution harms the world:
The Downside of LEDs
LEDs are considered one of the most energy efficient forms of light but they are disruptive for many species, including humans. Since LEDs are composed of light from all wavelengths, they resemble sunlight, more so than other bulb types. Unfortunately, these bright lights can disrupt human circadian rhythms and interfere with sleeping patterns. LEDs negatively affect humans and other species by stimulating the brain to wake up at night.
Threat to Human Health and Circadian Clock
The circadian cycle refers to the human body’s 24 hour day and night cycle. This cycle is crucial for human health because our bodies follow it for other biological functions such as cell regulation and hormone production. When artificial light continually disrupts our circadian cycle many severe health problems could arise. People are more prone to cardiovascular disease, depression, insomnia, and many other sleep disorders. Constant exposure to artificial light can also make melatonin production irregular, and in worst case scenarios may cause cancer.
Harmful for Insects and Bats
Insects, such as mosquitoes, are attracted to artificial light and spend extended periods of time around street lights and other bulbs. Unfortunately, a large number of insects end up dying because of the burning heat from the lights. The gravitation of insects towards street lights also has negative repercussions on the bat population. Some bat species are light-averse and are highly repelled by artificial light sources. And since more and more insects are gravitating towards artificial lights, bats have less food to eat.
Confusion for Proper Plant Growth
Flowering plants and trees need a certain amount of time in the darkness for proper development and growth. This specific photo period for plants is important for leaf shape, growth, and overall development. But with excessive light pollution their photo periods are constantly disturbed. Unfortunately, this has cascading effects on the pollinating insects and other species that rely on trees and flowering plants.
Distraction for Migrating Birds
Bright city lights can be misleading for nocturnal migratory birds. These migrating birds travel at night and use the setting sun and moon to navigate their route. Light pollution can confuse birds into thinking the lights are navigators and they can end up colliding into a building. Many migrating birds die from these collisions or become injured enough to be left for other predators.
Disruption for Freshwater and Marine Life
In rivers that run near or through cities, the migratory patterns of fish are increasingly disrupted. Light pollution confuses fish and has affected their foraging, predation, shoaling and reproductive rate. Marine ecology has also become negatively affected by artificial lights. When female sea turtles move to beaches to lay their eggs, they are put-off by any nearby lights. They want to lay their eggs in areas that are darker and less exposed, but sometimes artificial lights can be an obstacle. The bright lights negatively affect female sea turtles and their young.
Disturbance for Amphibian Reproduction
Frogs are nocturnal amphibians that also go through periods of hibernation. This hibernation period is also when they reproduce. Unfortunately, artificial light has begun to disrupt their reproductive cycles. It alters their senses to know when to breed and when to return to their home. As they become more desensitized, the frogs are missing their windows of opportunity to reproduce. As a result, they face breeding declines.
Difficulties for Astronomers
Artificial lights pose problems for scientists and researchers who want to observe and document objects in the night sky. Light pollution makes the sky brighter and makes it harder for them to take a smooth spectra. Their ability to study the night sky has been hindered by the overwhelming number of bright city lights.