Light Pollution

Lamentamos que esta página no esté disponible actualmente en español.

By Travelife, 16th May 2025

In this article, Travelife for Accommodation explains how light pollution can affect biodiversity and emissions, along with some tips for reducing it.

The night sky gets increasingly brighter through artificial light with over 80% of the world’s population living under a ‘lit sky’. This number is even higher in North America and Europe, where it almost reaches 99%. From 2012 until 2016, outdoor areas lit up by artificial light increased by 2.2%, as shown from satellite monitoring. In urban areas, artificial lighting comes from streets, buildings, offices, cars, advertisements, etc., lighting up the night for safety reasons and people who are working or enjoying nightlife in cities after the sun goes down. This excessive or inappropriate use of artificial light brightening up our night skies, known as ‘light pollution’, has negative effects on human health, wildlife behaviour, and the environment, not to mention our connection with the night time sky, as in some places we are losing the ability to observe the night sky with its stars and other cosmic objects.

Effects of light pollution on the environment

Naturally, light pollution contributes to global warming as extortionate amounts of electricity are used to light up the night, which emits high rates of CO2 and other greenhouse gases. However, light pollution is also impacting animal behaviours with detrimental effects as it affects matters including migration patterns and sleeping habits. For example, light pollution confuses sea turtle hatchlings who use natural light orientation to find their way back to the sea after their mother laid her eggs on the beach. The horizon over the sea is slightly brighter than the horizon over land, and hatchlings recognise this and use it as a navigation system. With artificial light brightening up the naturally dark beach at night, with light coming from accommodations or restaurants for instance, hatchlings can no longer find the quickest way the ocean and crawl towards the artificial light source instead, often resulting in their deaths.

Additionally, every year, light pollution results in the death of millions of migratory birds, such as geese, ducks, certain songbirds, and seabirds, as their migration patterns get affected in numerous ways. For instance, migrating species might set off on their migration journey earlier than usual when they are exposed to light pollution, and the necessary resources and conditions for breeding or survival might not be in place at the destination when they arrive. Furthermore, long distance migration birds could get distracted by artificial light sources on their way to or from their migration destination, which could lead to depletion of energy, that in turn could cause collisions with buildings or increased chances of predation. It also has effects on city birds who get disoriented by artificial lighting coming from buildings and homes, and often fly into windows or buildings with the occasional bird falling hundreds of feet down onto the street.

Effects of light pollution on people

In addition to the negative effects on wildlife, light pollution also impacts human health, for example through disturbing our sleep-wake cycle, which can result in daytime tiredness and sleep disturbances, but also impacts our immune system and stress response. It is even believed that it increases the risk of hormone-related cancers.

What can you do?

Unlike many other forms of pollution, light pollution is reversable and individually and collectively we can help and make a difference.

These are a few examples of things you can do to reduce light pollution:

Only use lighting when needed and ensure to switch off lights when leaving a room.

Use LED lighting.

Reduce the use of decorative lighting.

Close your blinds to ensure light does not travel outdoors, reducing the risk of bird collisions, especially when you live in a high-rise building.

Make sure that outdoor lighting is properly shielded and/or use motion sensors so lights only turn on when needed. You can also use coloured lighting and glow stones as they reduce the effect of light pollution.

Switch off electronic devices at least an our before going to sleep and keep lights switched off when using the bathroom at night to ensure your sleep-cycle will not get disrupted.

If you own a house, restaurant, or hotel on the beach, invest in turtle-friendly lighting and ask your neighbours to do the same. Turtles do not respond to warmer light, so it is better to use longer-wavelength LEDs instead of bright white-lights.

Participate in light-out campaigns, such as EarthHour. There are also other campaigns raising awareness for light pollution you could get involved in, for example World Migratory Bird Day 2025.

Light pollution is a topic most people are not familiar with. You can educate yourself on the topic, for example by reading blog posts and articles.