When you think of pollution, you might think of garbage on the ground, smoke in the air, or oil in the ocean. These are types of pollution that you can often see, feel, and sometimes even smell, and they have serious impacts on the health of both humans and wildlife.
However, there is one type of pollution that isn’t recognized as often: light.
Light pollution can obscure the stars or wash the night sky with a hazy glow; and it is something we all contribute to.
WHAT IS LIGHT POLLUTION?
DarkSky International, one of the most renowned worldwide authorities on light pollution, defines it as “the human-made alteration of outdoor light levels from those occurring naturally.”
So, what causes light pollution?
· Streetlights
· Downtown lighting
· Electronic advertising (Think electronic billboards or screens on the sides of buildings)
· Stadium/sports arena lighting
· Home lighting and porch lights
· Or any other human-made source of light
There are also four main components of light pollution.
Glare occurs when excessive brightness causes visual discomfort, such as headlights reflecting off your rearview mirror.
Sky glow is the brightening of the sky, particularly at night. This is what contributes to the hazy, dull appearance of the sky in and around urban areas.
Light trespass occurs when light falls where it isn’t needed, such as when streetlights cast light unnecessarily into the sky instead of just pointing down toward the street or sidewalk.
Clutter is an extremely bright, excessive, and often disorienting grouping of light sources. Think Times Square: hundreds of billboards and screens flashing with colors and patterns. That’s a lot of light!
SO WHAT?
You might be wondering what the big deal is about light pollution. It can be annoying, sure, but haven’t we all just become accustomed to it? How does it really affect humans or wildlife? Well, when we are exposed to light pollution, our circadian rhythms can be disrupted, leading to detrimental impacts to our sleep, mood, and stress levels. Light pollution can also create hazards while driving.
Glare caused by headlights, signs, and streetlights can cause visual discomfort or extremely limited vision while driving at night, potentially impacting anyone on or near the road.
WHAT ABOUT WILDLIFE?
Excessive light pollution can confuse, daze, or even “trap” migrating species. When blinded by nighttime lights, migrating birds may spend valuable energy trying to regain their bearings. However, they may not be able to escape the lights before becoming exhausted or colliding with trees, buildings, or even other birds.
Firefly populations may be critically impacted. Fireflies rely on their natural light to communicate with one another. Light pollution reduces natural darkness, which means fireflies may be less able to mate, find food, or defend themselves, which could be detrimental to their populations.
Research suggests that direct light, like headlights passing by, can disrupt firefly communication for as long as 20 minutes. Some species in Central Florida only flash for 40 minutes an evening, so you can see how this could be problematic for their reproductive success.
Bats may not know when to leave the roost. Bats use the cycles of sunlight and darkness as cues to know when to leave the roost and begin looking for food. When artificial lights remain illuminated after dark, bats may not know when to leave the roost; essentially becoming trapped! Though the bats may leave the roost eventually, this may disrupt their natural feeding and resting cycles, leading to poor health or exhaustion.
As with humans, the circadian clocks of wildlife species may become disrupted. Other mammals, birds, reptiles, and even fish rely on circadian cycles to hunt, forage, and sleep in the most efficient manner. When these cycles are disrupted, animals can waste time and energy, potentially missing out on food or rest.
WHAT CAN I DO?
Fortunately, we all play a role in contributing to light pollution, so we can all take steps to help reduce it!
The easiest ways to reduce your impact on light pollution begin at home. Here are some simple steps you can take:
· Change all outdoor lights to motion-activated to reduce the duration of light pollution
· Close your blinds, or curtains, at night to reduce light escaping into the yard
· Consider using string lights or lamps rather than overhead lighting
Additional suggestions can be found by going to darksky.org, the official website of Dark Sky International.
Outside of your own home, it can be difficult to influence lighting practices. However, one thing you can strive for is community education and communication. Share this article with a friend and talk about additional ways to reduce light pollution in Polk. Remember that we can all contribute - and each small contribution we make adds up, potentially improving the wellbeing of humans, wildlife, and natural areas globally. Take the time to turn out the lights, go outside, and look up at the night sky; you might be surprised by just how much you can see!
Did you know? Fireflies are still found in Polk County’s rural and urban areas. Our office has recent reports of fireflies on Lakes Howard and Rochelle in Winter Haven, Loyce Harpe Park in Lakeland, and along the rural roads and pastures in Fort Meade and other areas of rural Polk County
This article was written by Natural Resources Extension Program Intern, Ms. Hanley Renney, under supervision by Natural Resources and Conservation Extension Agent, Mrs. Shannon Carnevale.
