TURN OFF THE LIGHTS AT NIGHT!
Ask people to name the worst kinds of pollution, and most will mention dirty air over busy highways, oil spilled on beaches or mountains of plastic packaging. Very few will think of the glow that fills the sky above every town once the sun goes down. Yet light pollution is spreading fast, and experts say it comes mostly from streetlights and from illuminated billboards that shine from dusk until dawn. For migrating birds, which use the stars to navigate, this glow is a real danger: it confuses them, so many lose their way and fly into tall buildings.(lines 1–6)
Over the past decade, the Night Sky Alliance has tried to make more people aware of the issue. Founded by astronomy clubs and nature societies, the group now has more than 200 members around the world. To spread its message, the Alliance releases new guides and short films every year, each dealing with a different side of the problem. Its 2024 materials, for instance, were about office towers that stay brightly lit through the night although nobody is working inside.(lines 7–11)
Turning off more of these lights would bring real benefits. Empty shops and offices that remain lit until morning waste enormous quantities of electricity, and in most countries that electricity still comes from power stations that burn coal and gas. According to environmental scientist Rachel Moore, the savings could be dramatic. "Suppose every city turned off the lights it does not need after midnight," she says. "The electricity saved would be enough to power millions of homes. Fewer power stations would be burning fuel, too, and that means cleaner air for everyone."(lines 12–17)
Still, Moore believes that switching lights off is not enough by itself. "We also have to stop adding so many new lights every year, and that will not be easy," she explains. "Look at how many towns now light up every road and every park, including places where no one walks after dark. In an ideal world, streetlights would be on for just 5–6 hours a night, and only in places where people actually need them."(lines 18–22)
Of course, a light can go off for part of the night only if it has a timer, or a motion sensor that switches it on when a person comes near. Fitting such equipment to older streetlights is costly, since the old lamp usually cannot be adapted and must be swapped for a completely new one. Money is only part of the difficulty, though. Small towns rarely employ technicians who know how to set up sensors, so experts have to be brought in from other cities. Faced with this expense and effort, many local councils give up. "Unless the technology becomes cheaper and easier to install, most towns will never make the change," Moore warns.(lines 23–29)
Some governments are now acting on the problem. In several European countries, for example, a law already obliges shops and offices to turn off their lights and signs between 1 a.m. and 7 a.m. Environmental groups want to go further. They are campaigning for laws that would make every new streetlight face the ground and give off a warmer, softer light, which would help birds and insects find their way at night. "Laws like these could protect wildlife from much of the harm," says Moore. "With luck, people in cities will soon be able to look up at night and see the stars again."(lines 30–36)