The Dark Side to Light

When was the last time that you saw the Milky Way? I am not talking about a picture of the Milky Way, but seeing it with your very own eyes. For many of us, when we look out at the night sky, we only see a handful of stars because light pollution is blocking our view of thousands. We do not realize that our lights are causing pollution and impacting our planet.

But how harmful can light really be? Well, it has a bigger impact than you might think.

First off, we allow our lights at night to spill into surrounding environments and ecosystems, having significant effects on wildlife. Plants and animals cannot tell the difference between sunlight and artificial light, and they rely on the structure of night and day for many essential activities such as reproduction, nourishment, and concealment from predators. With us producing so much extra light at night, they cannot tell that the sun has set, leading to changes in migration patterns, predator/prey relationships, feeding techniques, and mating habits.

For example, birds who migrate using stars in the night sky are now having trouble migrating because the bright lights from cities confuse them. Frogs wait for nightfall to begin croaking so that they can find mates, but if nightfall doesn’t come, they won’t croak and frog populations begin to decline. Hatching sea turtles look towards the moon to find water, but it's hard for baby sea turtles to tell the difference between the moon and glowing porch lights. This often sends them in the wrong direction, making them easy prey. When the days grow shorter and there is less sunlight, trees know to shed their leaves to start conserving energy for winter. If we leave artificial lights on all night long, nearby trees can no longer tell when the seasons are changing, providing consequences for many animals who take cues from the trees to prepare for winter. In these ways, we can see that something so insignificant as manmade light does have an impact on wildlife.

But light pollution doesn't just affect plants and animals--it affects us too. Our bodies have a circadian rhythm (or a "biological clock"), which relies on night and day to produce the correct hormones at the right times. When the sun sets, our bodies produce melatonin which helps us sleep, boosts our immune system, lowers cholesterol, and helps our body function properly. When we are surrounded by artificial light at night (by outdoor/indoor lights, TVs, cell phones, etc.), our body does not send the signal to our brain to start producing melatonin. The altering of our circadian rhythm and lack of melatonin can significantly impact our overall health. Research from the International Dark-Sky Association (IDA) has found that artificial light can increase the risk of obesity, depression, sleep disorders, diabetes, breast cancer, and more for humans.

The IDA also states that on average, the U.S. alone uses about 120 terawatt-hours of energy on outdoor lighting, mostly to illuminate streets and parking lots. That's enough energy to meet New York City's total electricity needs for two years! The real kicker is that at least 30 percent of all outdoor lighting in the U.S. is wasted because most of the lights aren't shielded, and the light escapes into the sky where it is not needed, adding up to $3.3 billion and releasing 21 million tons of carbon dioxide per year (for perspective, to offset that much carbon dioxide, we would have to plant 875 million trees annually).

By making changes to curb light pollution, we could potentially cut energy use by 60-70 percent and save billions of dollars annually. Furthermore, reducing light pollution would also have a beneficial effect on our bodies by restoring our natural rhythm with day and night and allowing our body to produce the right hormones at the right times. Plants and animals would be able to regain their sense of navigation and predator-prey relations, helping populations of many species recover in the process.

So how can we take sustainable steps towards reducing our light pollution footprint? Try some of the following tips below to start living more light-conscious!

• Lights with dimmers, motion sensors, or timers should be used whenever possible.

• LEDs and CFLs (compact fluorescent lights) can help reduce energy wastage and protect the environment. When shopping, look for warm-white bulbs that are 3000K (color temperature) or less.

• All outdoor light fixtures should be fully shielded and pointed down towards the ground where the light is needed.

• Lights that are not needed should be turned off at night (this is especially important for businesses and organizations that leave their lights on at night).

• Join the International Dark-Sky Association in their fight to bring back the night. April 5th-12th is International Dark Sky Week, so be sure to share this article to raise awareness about light pollution.

By taking these simple steps, you can help make a difference in the fight against light pollution. If you are interested in learning more or curious about where we learned this information, check out the International Dark-Sky Association at darksky.org. I encourage you to check out their website and support the great work they are doing to bring back the Milky Way.

A special thank you to Simply Environment for collaborating to share this blog post! For more by Sustainable Saplings, follow us on Facebook, Instagram and check out our blog.