Light pollution: How lighting harms the environment

Scientists have found that eco-friendly LED lamps have a negative impact on nature. In general, the problem of light pollution receives little attention, although it has an adverse effect on both the environment and humans.

Scientists have long been saying that light pollution in cities disrupts the biological cycles of ecosystems. Artificial light even penetrates to the bottom of the seas. A study conducted by the University of Plymouth in the UK showed that artificial lighting in coastal cities affects three-quarters of the habitats of marine animals. Plants and animals depend on the daily cycle of light and darkness to manage reproduction, feeding, sleep, and also to protect themselves from predators. Nocturnal animals sleep during the day and are active at night. Light pollution radically changes their habitat, turning night into day.

Light pollution is excessive, incorrectly directed artificial (usually street) light. Too much light pollution has consequences: it blurs the starlight in the night sky, interferes with astronomical research, destroys ecosystems, has an adverse effect on human health, and wastes energy.

Today, approximately 23% of the Earth’s surface is in the light pollution zone. Almost 80% of the population is exposed to it, including 99% of those living in Europe and the United States.

Every year, there is more and more light in the world, the area of ​​artificially illuminated areas increased by 2.2% from 2012 to 2016, and the brightness of light increases by 1.8% annually. The most paradoxical thing is that this is due to the transition to energy-efficient LED lamps, which are considered more environmentally friendly.

Why are eco-friendly lamps not eco-friendly?

It turns out that energy-efficient lighting, which reduces greenhouse gas emissions from energy production, harms the environment more than traditional sodium lamps (which produce a yellower light). Scientists from the UK Centre for Ecology and Hydrology have found that “eco-friendly” LED street lights create worse light pollution for insects than traditional sodium lamps. The number of moth caterpillars in hedgerows along rural roads in England was 52% lower under LED lighting and 41% lower under sodium lighting compared to nearby unlit areas.

In the grass, the number of moth caterpillars near LED lamps was a third lower than in unlit areas, while old lamps had little effect on the numbers. According to scientists, LED lamps are more energy efficient, but emit more blue light, which insects are not adapted to.

In general, any artificial lighting has a negative impact on nature. For example, street lights make insects more visible to predators, interfere with feeding, and reproduction. When illuminated, butterflies are more vulnerable to predators. This means that they lay fewer eggs. Street lights also make it difficult for male fireflies to attract a mate. It was found that bugs in dark areas usually found a mate after one night of illumination, while in illuminated areas it took up to 15 nights. In England, the number of fireflies has decreased by three-quarters since 2001.

The negative impact on insects is increasing every year, and this is not only due to light pollution, but also due to global climate change, deforestation, etc. Insects are by far the most diverse and numerous animals on Earth; there are millions of species, and they outweigh the combined weight of humans by 17 times. They are essential to the ecosystems on which humanity depends: pollinating plants, providing food for other creatures, and participating in the cycle of matter.

For example, moths play an important role in pollinating crops such as peas and oilseed rape. Moths pollinate crops at night, when bees and other daytime pollinators go to sleep. However, artificial lighting also has the opposite effect on pollination. Researchers found that pollination increased in areas of fields where lights were on all night, as butterflies flocked there. Despite this, scientists still urge to keep any disruption to natural systems to a minimum.

In Florida, hundreds of newborn turtles die every year because the coastline is built up with hotels and roads. The fact is that sea turtles lay their eggs on dark beaches, which are becoming less common. Newborn turtles usually crawl towards the sea, as this is a brighter horizon for them, but artificial lighting leads them astray, and this is how they die.

You can see light pollution on a special interactive map.

Light pollution also has a negative impact on human health by disrupting our biological clock. The spread of artificial lighting means that many of us no longer experience truly dark nights. Research shows that artificial light at night can negatively impact human health, increasing the risk of obesity, depression, sleep disorders, diabetes, cancer, and more.

Every year, about $7 billion is spent on the environment and human health due to the negative effects of light pollution. The problem is that access to more energy-efficient lamps forces people to install new light sources. Consequently, all the benefits of energy saving are lost. This is called the Jevons paradox — the efficiency of resource use can increase the volume of its consumption.

What solutions exist?

The problem of light pollution runs into a safety problem — it is impossible to simply turn off the lights in cities, although this has a positive effect on the environment. In some areas of the UK, municipalities began to turn off street lights in the dead of night, when there are practically no people on the streets, in order to save money. After this, scientists discovered a positive dynamics of reproduction of some insects. Research shows that turning off the lights from midnight to dawn is enough to prevent behavioral disorders in animals.

However, not all cities and countries are ready to turn off the lights at night, so the International Commission on Illumination adopted recommendations that prescribe the permissible levels of unwanted light for different natural zones. Unwanted light, or irrational use of light, is one of the main causes of light pollution. These are situations when light falls on an area or objects that do not need to be illuminated. The main cause of unwanted light is design errors.

The International Dark-Sky Association has formulated five rules that should be followed to reduce the negative impact of light pollution:

1. Usefulness. It is necessary to understand whether it is really necessary to illuminate the area. Experts suggest considering how light will affect the area, including wildlife. There may be other ways to reduce the need for permanent lighting, such as reflective paint.

2. Clear purpose. If you can’t avoid lighting, you need to get rid of unwanted light, i.e., point lamps and lanterns, only at the places that need to be illuminated.

3. Light level. Light should not be brighter than necessary. Experts urge using the minimum required illumination level.

4. Control. Light should only be used when it is useful. Motion sensors or timers can help with this.

5. Color. Use warmer shades if possible. Experts advise limiting short-wave blue-violet light to the minimum necessary, as it is the most harmful to insects and animals.

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