Earth Hour: let's talk about light pollution

Earth Hour is a global environmental movement organized by the World Wildlife Fund. It aims to raise awareness and inspire people to take tangible action for Nature by inviting everyone to switch off their lights for an hour on Saturday, March 27th, at 8:30 pm local time. Millions of people from over 190 countries take part in this event annually. More than a mere symbol, Earth Hour is a catalyst for urgent change.

Age of Union takes the opportunity to reflect on Light Pollution, a phenomenon that has drastically increased since the 1950s and is perceived today as one of the most chronic environmental disturbances on Earth. The good news is that, unlike many other forms of pollution, this one is easily reversible. Let us dive into what exactly light pollution is and explore how each one of us can be part of the solution.

Starry Night of Alps by Babak Tafreshi

Why has the Milky Way disappeared from our sight?

A century ago, anyone could see the Milky Way in the night sky. Nowadays, if you live in a city, try to look up at the sky: you will likely not see any resemblance to a constellation. Light pollution is the excess of artificial light obstructing the visibility of the sky. Skyglow is a side effect of industrial civilization. Street lamps, commercial store lights that stay on throughout the night and even the light from your front porch or yard are sources of luminous pollution.

Light pollution facts:

° 83% of people in the world are impacted by light pollution.

° In places like Las Vegas, the glow of the city’s lights can project over 40 miles (70km) away from its source.

° The Milky Way is hidden from more than one-third of humanity

° 88% of Europe and almost half of the United States experience light-polluted nights

° With an estimated light pollution growth of 6% a year, all of the developed world may lose its dark skies by the end of the 21st century.

° If you want to see how bad is the light pollution where you live, check out “The New World Atlas of Artificial Sky Brightness

(Sources: National Geographic, Science Advances, Skyglow Project)


Why is light pollution dangerous for ecosystems and humans?

Light pollution has a significant impact on interrupting the day-night cycle that nature, animals and humans depend on. This cycle is engraved in the DNA of all species, from nature to animals, to humans. 

Ecosystems (plants, insects and animals)

Plants use photosynthesis to transform water and carbon dioxide into glucose during the day. Light is key to this energy-generating process. When the sun sets, they stop photosynthesizing. Most plants switch at night from photosynthesis to the opposite process, respiration, in which carbon dioxide and water are produced rather than consumed.

In regards to wildlife, many animals and insects are nocturnal, meaning they are mainly active at night. Birds’ migratory habits, sea turtles’ nesting locations and mammals’ reproductive periods also rely on this day-night cycle. The loss of dark nights disrupts the insects, mammals, amphibians and birds’ internal patterns, having a direct impact on their rapid population decline (source: UN environment program).

"Light pollution can disrupt critical behaviour in wildlife. It can stall the recovery of threatened species and interfere with their ability to undertake long-distance migrations, reduce breeding success and their chances of survival. Light pollution is a growing phenomenon which needs to be considered in conservation efforts and which can be avoided or minimized through nature-friendly lighting design and management." – Amy Fraenkel, Executive Secretary of the Convention on Migratory Species



The human body's internal clock or “circadian rhythms” – which regulates the hormone system, eating habits and digestion process, body temperature and sensation of tiredness throughout the 24 hour period – is directly related to the light cycle. The amount of brightness around us is captured by the optic nerve that sends the information to the brain. This is why, despite being night time, electronic screens (blue light) and artificial indoor or outdoor lights convince the brain that it is daytime, which interferes with the body’s biological clock. This confusion can exacerbate serious health problems such as insomnia, depression, bipolarity or obesity (source: National Institute of General Medical Sciences)

Beyond just health, a clear night sky impacts our thoughts and our core values as well. A professor at the University of California suggests that those who live in areas that are not affected by light-pollution show more empathy are kinder and less materialistic. 

“Philosophers have written about how a big beautiful sky makes you feel like you’re part of something big, like it’s sacred, like it’s purposeful (...) By contrast, a smoggy sky that is closing in on you or a night sky that’s filled with pollution kind of weighs heavily on your consciousness” (source: Dacher Keltner for National Geographic).

The Milky Way Arcs over Mountain Lake by Babak Tafreshi

What can we do to prevent light pollution?

Check all the lights that you use on a daily basis, such as inside and outside your home, in the common areas of your building, and even those from your personal electronic devices, to see if they follow the guidelines to minimize the harmful effects of light pollution. Three main points to keep in mind for anyone in control of a light switch: the lights should be shielded to reduce emission towards the sky, they should never be brighter than necessary and the light's temperature should tend towards warmer tones rather than cold,  such as oranges instead of blues. 

The International Darksky Association (IDA) encourages any citizen to use lighting wisely and propose a list of things to do.

In order to be light pollution friendly, lighting should:

° Only be on when needed

° Only light the area that needs it

° Be no brighter than necessary

° Minimize blue light emissions

° Be fully shielded (pointing downward)

(Source: IDA)

Milky Way and light pollution in the horizon by Masoud Ghadiri


Article written by Mariette Raina.
Mariette Raina writes articles that discussing environmental, spiritual and artistic subjects.
Mariette has a Master's degree in Anthropological studies and vast experience within the Fine Arts field. She has contributed to numerous projects for Dax Dasilva since 2016. She is currently Head of Research for Age of Union.

Photo 1 "A Galactic Night of Planet Earth" by Babak Tafreshi
Photo 2 "Starry Night of the Alps" by Babak Tafreshi
Photo 3 "Light Pollution" by Nosara Civic Association
Photo 4 "The World at Night" by Jeff Dai
Photo 5 "The Milky Way Arcs over Mountain Lake" by Babak Tafreshi
Photo 6 "Milky Way and light pollution in the horizon" by Masoud Ghadiri

Special thanks to the photographers Babak Tafreshi, Jeff Dai and Masoud Ghadiri for lending us their magnificent photos contributing to our article.