Light Pollution Data

Fun facts and figures about how artificial light is reshaping the night — worldwide and nationally.

Global facts

What is happening to the night sky across the planet.

Starry rural sky with a bright dome of light pollution glowing along the horizon

~10%

brighter each year

The night sky is brightening by roughly 10% per year in many populated regions — a child born today may see far fewer stars by adulthood.

Milky Way over a bog with city skyglow spreading along the horizon

1 in 3

never see the Milky Way

About 80% of the world's population lives under light-polluted skies, and around 1 in 3 people can never see the Milky Way.

Satellite view of Earth at night showing networks of artificial light

+2%

lit area per year

Artificial light at night grew in both extent and brightness by around 2% per year in the 2010s worldwide.

City lights along the France-Italy border photographed from orbit at night

99%

of Europe & North America

Roughly 99% of people in Europe and North America live under skies brighter than the natural night.

Flock of birds flying overhead against a pale sky

Billions

of migrating birds

Billions of migrating birds navigate by stars; bright cities pull them off course and cause mass window collisions each year.

Sea turtle hatchling crawling across sand on a beach

Wrong way

for hatchlings

Sea turtle hatchlings crawl toward the brightest horizon — beachfront lighting sends them inland instead of to the ocean.

Street lamp glowing brightly against a dark night sky

Blue light

scatters the most

Blue-rich LED light scatters most in the atmosphere, so the switch to cool white LEDs made skyglow worse even where energy use fell.

National facts (United States)

How much light the US sends into the sky — and what it costs.

Street lamp glowing brightly against a dark night sky

30%

of outdoor lighting is wasted

Roughly 30% of outdoor lighting in the United States is wasted by shining upward or sideways instead of on the ground.

City skyline at night glowing under a bright orange haze

$3B

wasted every year

That wasted light costs the US roughly $3 billion each year, along with about 21 million megawatt-hours of electricity.

The United States photographed at night from space, glowing with city lights

99%

of the continental US

Roughly 99% of the continental US population lives under skies too bright to be considered naturally dark.

Milky Way over a bog with city skyglow spreading along the horizon

80%

have never seen the Milky Way

About 80% of North Americans have never seen the Milky Way with their own eyes.

Starry night sky over a dark landscape with little artificial light

A handful

of states still have dark skies

Only a handful of US states still hold large regions of pristine dark sky, mostly the Mountain West and desert Southwest.

The Headlands International Dark Sky Park visitor center under a starry sky

200+

certified Dark Sky Places

More than 200 certified International Dark Sky Places exist worldwide, and the US holds the largest share of them.

Lowell Observatory in Flagstaff, Arizona at twilight

Flagstaff

first Dark Sky City

Flagstaff, Arizona became the world's first Dark Sky City, cutting skyglow with shielded fixtures and curfews without reducing safety.