Cities and light pollution are well acquainted, but the growing trend of replacing old streetlight bulbs with more energy-efficient LED ones is making cities glow even brighter after sunset.
Cities at Night is studying the level of light pollution in various cities, and is collecting images of Earth taken by astronauts at the International Space Station to show that increased brightening. Tech Insider compiled some of the astronauts’ images from a few years back and more recently for Milan, Mexico City, Seoul and Los Angeles.
The change in Los Angeles, as in the other cities, shows a much higher concentration of blue-hued LED light amid the city and its sprawl.
In addition to changing the view of the night sky, LED lights have been connected to confusion for nocturnal species (altering their hunting habits), disruption of trees’ growth patterns, and even human sleep disorders.
From Tech Insider:
LEDs also worsen light pollution by giving off more blue and green light than the high-pressure sodium lights they normally replace … It can also mess with our internal clocks. We produce melatonin at night to help us sleep, which is regulated by light and dark cycles. If we’re exposed to light at night, this can suppress melatonin levels, leading to sleep disorders or other problems such as headaches, anxiety, and obesity.
Check out the rest of Tech Insider’s contrasting pics here.
Marielle Mondon is an editor and freelance journalist in Philadelphia. Her work has appeared in Philadelphia City Paper, Wild Magazine, and PolicyMic. She previously reported on communities in Northern Manhattan while earning an M.S. in journalism from Columbia University.