There are no sea turtles in PA

When you first start learning about light pollution, inevitably you’ll run across someone bemoaning the fact that light pollution hurts sea turtles. It causes sea turtle hatchlings to crawl away from the ocean, where they get eaten by predators or run over by cars.  This is sad, of course. I like baby sea turtles as much as the next person. But there are no sea turtles in Pennsylvania. So, why should we care about light pollution?

As it turns out, excess light at night has serious consequences for things we love here in PA. Consider:

• Light pollution has been shown to cause all sorts of problems for birds. It disrupts migration, changes when they lay their eggs, and causes sleep disruption. Maybe some of you remember the evening in October 2020 when over a thousand migrating birds were lured in by lights in Philadelphia and died when they struck buildings there. Light at night also causes birds to spread viruses for twice as long, possibly due to lower levels of melatonin, which can impact the immune system. This is especially bad for birds like the ruffed grouse, the state bird of Pennsylvania, who have been hard hit by West Nile virus.

• You might not think light pollution could hurt plants, but it does. This makes sense once you realize plants literally eat light. Light pollution can affect plant growth, making them more susceptible to cold snaps and disrupting their relationship with pollinators. Consider this the next time you look at mountain laurel (PA state flower) or Eastern hemlock (PA state tree).

• Too much light at night even harms fish, such as the brook trout (PA state fish), and other aquatic creatures. This is because many marine animals rely on the natural day-night cycle to time their reproduction, feeding, and hiding from predators.  Too much light causes anxious behavior and reduces reproduction.

This is bad news for creatures that we are proud to have here in the Commonwealth. The good news is light pollution has simple solutions: follow the principles of lighting only when and where you need it, and only as brightly as you need it.  So whether you’re a birdwatcher, an angler, or someone who just likes to see flowers bloom each spring, do your wild Keystone neighbors a favor and keep the night dark in PA.