Remember being a kid and spending countless hours on summer nights looking up at the night sky, trying to discern constellations and looking for shooting stars to make a wish?

For an increasing number of children and adults around the world, that’s just a story, a myth, something people do in isolated places like Wyoming and the northern stretches of Canada where the population for miles around can be measured in small digits.

World map of artificial sky brightness: Source Science Advances
World map of artificial sky brightness: Source Science Advances

A new paper, “World Atlas of Artificial Night Sky Brightness,” published in the journal Science Advances found that some 80% of the world’s population lives in an area where lights are too bright to see the evening sky.

Light Pollution over North America. Google Earth / Fabio Falchi
Light Pollution over North America. Google Earth / Fabio Falchi

99% of people living in Europe and the United States are affected by Light Pollution

Light pollution, as the phenomenon is also known, comes from street lights, buildings, traffic, homes, industrial complexes, you name it. The glow prevents the light from stars to be easily noticed, if the stars can be seen at all.

Under the Milky Way in the Atacama desert. Source: Luis Calçada
Under the Milky Way in the Atacama desert. Source: Luis Calçada

Canada and Australia are among the least polluted places on the planet, making it easier to look up and find the Big Dipper or the Southern Cross on nights when cloud cover doesn’t impede viewing. But South Korea, Germany, the United States and Saudi Arabia are finding skies suitable for stargazing to be increasingly rare.

The study reports that street and outdoor lighting using 4000K lamps could increase light pollution two-and-a-half times. LED lighting is making the problem worse and more intense.

“The new atlas provides a critical documentation of the state of the night environment as we stand on the cusp of a worldwide transition to LED technology. Unless careful consideration is given to LED color and lighting levels, this transition could unfortunately lead to a 2- to 3-fold increase in skyglow on clear nights” warns Fabio Falchi of the Italian Light Pollution Science and Technology Institute, who led the research team.

Los Angeles in 2010 (before implementing LED), and after in 2012. Source: GIPFY
Los Angeles in 2010 (before implementing LED), and after in 2012. Source: GIPFY

But so what, right? Who cares if we can’t see the stars at night up in the sky? What did those burning balls of gas millions of miles away ever do for us? Stargazing is the stuff of silly minded poets and dreamers; the ability to see the stars has no practical purpose whatsoever. Right?

Wrong.

The report also notes that light pollution kills 300 million to 1 billion birds each year. Birds dying means an uptick in the insect population, which can lead to increases in communicable diseases. Further, it wastes energy costs, keeping all those lights on, and sleep loss and deprivation among people leads to lost productivity at work, meaning there’s a financial problem as well.

Looking at maps of skyglow across Europe is like looking at skin with some kind of disease: blotchy, deeply intense patches of red indicating a near constant canopy of light even in the depth of evening.

Europe at Night from ISS
Europe at Night from ISS

While most of Europe and Asia is ablaze in bright blues, greens and reds in the report’s maps on the intensity of light pollution, North Korea disappears. The country mandates turning off all lights at night, so skyglow is nearly nonexistent there.

One of the study’s authors, Dan Duriscoe, a scientist with the US National Park Service, says even a small change to the brightness of the night sky from overhead lighting is considerable—more than half the animal population is nocturnal, and not being able to see and navigate by the sky can throw off entire ecosystems.

“A site with sky brightness just 1% above natural zenith probably has much more skyglow near the horizon, because it is probably in a situation where it lies within the light dome of something else hundreds of kilometers away,” he says. “This is where the model is powerful for predicting light pollution threats from distant cities now and in the future. As populations grow and spread, areas with no evidence of artificial light are going to get much harder to find.”

The Milky Way
The Milky Way

More and more of the world’s population can’t look up and see any trace of the Milky Way. As more municipalities adopt LED street and exterior lighting, that number will decrease, as might the population of seabirds in the Channel Islands or the breeding population of Xantu’s murrelets along the coast of California.

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Amber Healy

Amber Healy has been writing, both personally and professionally, since she nagged her hometown paper to give her an internship in 1996. She's a big believer that the most fascinating stories are hidden under layers of seemingly boring drivel.