In an attempt to reduce energy consumption and make street lighting more environmentally friendly, Europe has been switching to LEDs in its street lights. However, it’s not necessarily a good choice, at least not in all aspects. The switch to LEDs is already visible from space, as well as the light pollution they cause. Of course, it’s not only our photos and the view of the night sky that are being affected. As scientists warm, the increased use of LED lights will also mess with living creatures and their life cycles, including both animals and humans.
In a study published in Science Advances, a group of scientists published nighttime color maps they created from the ISS images of Europe. The maps were created for the periods between 2012 and 2013, and between 2014 and 2020. They display the before and after of the spread of LED street lights, showing us the changes in spectra of color and light intensity emissions.
According to the results, there has been a color shift as the lighting technology changed. White LED lights give away blue light compared to the high-pressure sodium lighting which gives away a yellowish glow. In addition, the light has become more intense with the implementation of LEDs. So why is all of this concerning? Of course, the intense glow of the LED lights will affect the view of the night sky, making our nighttime photos even crappier than they are now. It makes it even more difficult to find a dark spot and take photos of the night sky. But more importantly, light pollution affects sleep and life cycles in humans and animals, which could have major consequences. For humans, the blue light of LEDs inhibits the exposure of melatonin, the hormone that makes us sleepy and that is naturally stimulated by being in the darkness just before sleep. And if you’ve ever been sleep deprived for longer periods of time, you know what it does to you. Thankfully, we humans can at least use sleep masks, dark curtains, etc. to help us fall and stay asleep. But what about animals? They can’t just conclude “that’s just a street light, I won’t use it for navigation.” The use of LED lights can largely affect animals and their life cycles. “Many times the nighttime is the time to eat, pollinate, navigate, nest, or rest, and all those processes are disturbed by the artificial light,” says Alejandro Sánchez de Miguel, the lead author of the study. This kind of light pollution harms animals sometimes by exposing them to predators, “other times directly by messing up with their physiology,” Sánchez de Miguel explains. But there are some upsides to the blueish tint of LEDs. Thomas Kilkenny of the Institute Sleep Medicine at Staten Island University Hospital said that it could be beneficial in some situations. “Blue light added to the streetlights may make people feel more awake when they are driving and decrease accidents,”he explains. But as I mentioned, the downside is the harm it could do to your sleep while you’re in your bed. “Sleep deprivation is already a major problem in society and in itself may lead to more traffic accidents, illnesses, depression, and lost time at work,” Kilkenny warns. [via Popular Science; image credits: Sánchez de Miguel et al.]
