When it Comes to Light Pollution, Red Lights Get the Green Light

February 28, 2025

It’s dark these days. For a period of time on either side of Winter Solstice, we’re treated to the least amount of sunshine all year. Depending on the longitude where we live our lives, we’re somewhere between utter darkness and just slightly dimmer than usual. For some, wintertime’s lack of light might be mitigated by light pollution.

Unlike Styrofoam cups, single use sporks and plastic bags, light pollution has silently seeped into our lives, coloring our nights with an unwanted artificial glow.

Photo Credit: David Lorenz – Center for Climatic Research

Light pollution takes three main forms, each of which we all can relate to:

Glare: When we get blinded by LED headlights and are left unsure about navigating the road ahead, that’s glare.
Light trespass: the motion sensor lights your neighbor installed on the garage that light up every time their cat walks by, bathing your bedroom in rising sun quality illumination, that’s this one.
Skyglow: Even though stars are more numerous than grains of sand on a beach, when we look up and think “I see like twelve stars,” that’s because of artificial light brightening the night sky, et viola, “skyglow”.

Besides being an annoying and blinding bummer, the impacts of light pollution are quite insidious. From disrupting our sleep cycle (which affects many areas of our lives), to impacting animals’ hunting, navigation and reproductive behaviors, we are beginning to understand the significance of light pollution’s negative impacts.

Now for the good news: there are areas where darkness still reigns supreme. Distance from population centers often equates to less of all types of light pollution and wonderfully darker landscapes. And, in even better news, Holiday River Expeditions runs trips in some of the absolutely least light polluted areas of the country (they even have stargazing specific adventures).

When we head out to immerse ourselves in these places, we always plan ahead and prepare (Leave No Trace principal number one!) to minimize our impact and care for the environment. When it comes to preventing the spread of light pollution to these wild and dark places, our top pick is to limit the use of LED lamps and make sure our light sources have a red-light option.

Here’s the rationale behind our reasoning:

For the non-optometrists in the audience, it turns out our eyeballs have cones and rods. Cones help us see colors during the day, but don’t operate in dimmer conditions. Rods are responsible for seeing black and white in low light, they don’t work as hard in daylight. So, as it gets darker, our cones log out and our rods sign in. Here’s why this matters…
Let’s be honest, when shopping for that new headlamp, we all geeked out on the light’s lumens (the measure of the perceived power of visible light emitted by a source). It turns out what’s really being conveyed with lumens is our ability to instantly blind everyone in camp. Since white LED light peaks in intensity at the blue-green end of the visible spectrum, it breaks down a protein in our eyeballs which allows our rods (the night shift) to operate. Once that happens, it takes 10-20 minutes to regenerate the protein and fully recover from the flash of your tent-mate’s lamp. Ouch.
To avoid being a perpetrator of light pollution, make sure lamps have a red bulb feature. Because red light is at the other end of the visible light spectrum, it doesn’t lead to temporary blindness. Most newer headlamps have this option, but for the DIY inclined, red brake light repair tape from an auto store or a red balloon (cut off the neck, stretch over lamp) can work too.

Spending a dark night under a blanket of stars resonates deeply in our experience. And not only is it a spectacularly pure pleasure, but studies also show that when we live our lives according to our natural circadian rhythms, letting cycles of light and dark dictate our activities, we have an opportunity to heal some of the more modern damage caused by our stressed out, sleepless and constantly distracted lives. Grab your red lamp, give us a call and book an adventure somewhere dark and lovely!

Eli Shostak is a Senior Lecturer of Adventure Education at Fort Lewis College. A former river guide, NOLS Course Leader, and sea kayaking instructor, he is a firm believer in the power of shared experiences in wild places. Eli is dedicated to using his expertise in mindfulness, leadership, and expedition planning to facilitate journeys for finding the personal and interpersonal benefits of exploring diverse landscapes. His favorite game to play on trips is called “Knuck Tats,” something you’ll have to ask him about.