Light Pollution So Bad, 80 Percent of Americans Can’t See Milky Way Anymore

Map of North America’s artificial sky brightness. Fabio Falchi et al./Science Advances

Light pollution blankets America so extensively, almost four out of five can’t see the Milky Way at night from where they live.

And the United States is not even in the top 20 of the most light-polluted countries, according to a new global atlas of light pollution, recently published in the Science Advances journal.

World map of artificial sky brightness. Fabio Falchi et al./Science Advances

Light pollution contributes to many problems of our civilization. The main problem seems to be that it interferes with the natural day/night cycles of living things.

It can cause birds to migrate too early, too late, stray off course, or hit buildings. Baby sea turtles have trouble finding the sea because of artificial lights, according to the International Dark-Sky Association.

The pollution hurts people too.

Lack of darkness disrupts people’s sleep cycles, including the production of melatonin, the hormone responsible for synchronizing our biological clock.

Work and exposure to light at night has been linked to breast and prostate cancer, diabetes, heart disease, and obesity, according to a Harvard Medical School article.

And the problem may get much worse.

For example, for years, cities have been switching from high-pressure sodium (HPS) street lights to LED—which are a longer lasting and more energy-efficient light source. But LEDs produce more than two times the light pollution than HPS lights, according to the research behind the light pollution atlas, led by Fabio Falchi of the Light Pollution Science and Technology Institute.

Not only do our eyes perceive the LED light as higher pollution, but it increases the amount of light in the blue spectrum. And blue spectrum light is the most disruptive to sleep cycles.

“Light at night is bad for your health, and exposure to blue light emitted by electronics and energy-efficient lightbulbs may be especially so,” the Harvard article states.

So which country is worse off?

Singapore. “Where the entire population lives under skies so bright that the eye cannot fully dark-adapt to night vision,” the paper states.

A few small Arab countries follow closely—Kuwait, Qatar, and United Arab Emirates—which all have such severe pollution that it reaches over 90 percent of the population.

Countries whose populations are most exposed to light pollution. Color ranges are shown on the right and indicate the pollution level. Fabio Falchi et al./Science Advances

Almost 40 percent of Americans are affected by the most severe light pollution. In the European Union it’s about 20 percent of the population.

Countries of the G20 group whose populations live under skies polluted by specified artificial sky brightness. Color ranges are shown on the right and indicate the pollution level. Fabio Falchi et al./Science Advances

One the other hand, people in many African countries like Chad, Central African Republic, and Madagascar, still mostly enjoy pitch black nights lit by an awe-inspiring, star-filled sky.

Countries whose populations are exposed to the least light pollution. Color ranges are shown on the right and indicate the pollution level. Fabio Falchi et al./Science Advances