It’s no secret that the Earth is now brighter than it has ever been in the past. An abundance of street lights, billboards, stadiums, and cars is making the Earth glow to the point that the light is clearly visible from space. Sadly, light pollution also makes space less visible to us.
Moreover, it is a huge source of wasted energy.
That’s why researchers in Tuscon, Arizona, are using satellites to measure how much light is being emitted in the city. The experiment has yielded some impressive results and shows just how much energy is being wasted night in and night out.
At 1:30 every morning for a 10-night period, the city of Tuscon went dim. More than 14,000 streetlights had their brightness turned down temporarily so that satellites overhead could observe the change.
Though it doesn’t sound drastic, the difference is detectable from space. However, the team behind the research discovered something even more surprising. Just 20 percent of the light detected by satellite images came from streetlights.
Dr. Christopher Kyba, a physicist who led the experiment, said that most of the pollution comes from other sources, including things like stadiums, lit buildings, floodlights, and parking lots. He says, “That’s really important information for policymakers and light pollution activists.”
“This does make it more difficult to solve, because there are so many contributors. It means everyone has to get together to decide what lights need to be lit at night, and how brightly,” Kyba adds.
Indeed, light pollution is a serious problem in its own right. A 2016 study found that up to 80 percent of the global population may never experience a truly dark night sky. Aside from that, the artificial glow can disrupt animals who are more accustomed to a natural light-dark cycle.
Of course, light pollution isn’t directly harming the planet. Energy waste, on the other hand, is.
Addressing the Problem
The recent satellite study provides actionable data to help cut back on energy waste from inefficient nighttime lighting. The International Dark Sky Association estimates that about 35 percent of artificial light is being wasted. Thus, the U.S. alone spends $3 billion a year on “making the sky glow.”
Fortunately, the problem is fairly easy to address. It doesn’t involve getting rid of streetlights or preventing people from turning on their lights at night. Rather, redirecting the lights to be more effective actually cuts down on energy usage.
A church in Slovenia decreased its power consumption by 96 percent simply by adding masks to its floodlights to ensure they only shine on the building. This allowed the church to get rid of some of its lights and limit its power consumption in the process.
Kyba says, “A lot of people talk about climate emergency but never talk about light pollution. But it’s an important part. And at night, when most of us are asleep, all that electricity could be going to other things—charging electric vehicles, for example.”
“It’s the kind of thing that can be done with a little bit of cleverness and the will to take action,” he adds.
Indeed, with the world facing a serious environmental reckoning, it is important to take small steps like these to conserve energy whenever possible. Unlike other climate actions, limiting energy waste from nighttime light also yields some immediate results. For one, we’d get a clearer view of the starry night sky.