The officer let us go with a warning and an admonition - “Be careful on the mountain, tonight.” It was 1:30 a.m., almost time for the mostly working-class bars in Leadville to close.  As I passed the police on Harrison Ave doing 32 in a 25, I guess I looked suspicious.  He pulled me over right in front of Wild Bill’s hamburger joint.  As I had been advised by a Colorado State Patrol officer who also happened to be a close friend, I turned off the engine, opened my window half-way, turned on my dome light, and put both of my hands on the wheel.  As police go, this guy looked bigger and more intimidating than most.  After I assured him that we were just a couple of crazy hikers trying to bag a fourteener under the full moon, his look of concern melted into mild amusement. We were headed to the Mount Elbert trailhead and we still had a 20-minute drive ahead of us.

Just south of Leadville, we turned off Highway 24 toward the Fish Hatchery but took a left before we got there.  From there we followed Halfmoon Creek to our destination.  At the parking lot, we opened the thermos of coffee and finished the burritos we got at Santiago’s earlier that evening. The air was cool for early-August but filled with the sticky sweet smell of pine.   Steam rose as we poured the hot liquid into our cups.  The smell of the coffee mixed with the greasy chorizo tricked our bodies into thinking it was a reasonable hour to be starting a hike and before long we were on the trail. 

The full moon that promised to light our way had been hidden most of the night under heavy clouds to the east.  Occasionally, it would find a small gap and light up the countryside, throwing shadows of trees, houses, billboards, fences, and cows across the landscape.  In the parking lot, the moon was again obscured by clouds, but our weather app promised clear skies by morning.  Once we got into the dense stands of Engelman Spruce and Subalpine Fir, vegetation and clouds completely obscured the sky.  It was dark.  We donned our headlamps to keep from tripping on the rocks and tree roots as the trail started to climb the north side of the mountain.  As we climbed into the narrow beams of our headlamps, I remembered the officers warning - “Be careful on the mountain!” - and I was thankful for our lights.  A twisted ankle or a blown-out knee even just a mile or two deep into the backcountry would not be a pleasant experience.  Losing the trail or missing a trail sign could also ruin your day.  We really needed that light.  We had two jobs that night: don’t trip, and stay on the trail, and physiologically, our eyes were not up to the task.  We needed our lights to stay safe.  

After about 2 hours, the skies cleared as promised. At about the same time, we started transitioning from the forest to the alpine tundra, passing the twisted, strained shapes of the Krummholz.    The full moon was now shining in all its spender, and the tortured trees cast odd, demonic shadows along the trail.  We emerged from the forest into one of the brightest moonlit landscapes I have ever seen. We could easily see the trail snaking up and then disappearing behind the false summit of Elbert.  The muted colors of the granite slopes were apparent and only a few of the brightest stars, Vega, Altair, and Capella, were visible.  The beams of our headlamps were quickly absorbed by the surrounding light.  Our eyes were more than capable of getting us to the top of the peak safely.  Our lights went back in our packs. 

There are times and places when artificial light is needed.  It keeps us safe.  It helps us complete our tasks.  There are other times when our lights are unnecessary, useless, and wasteful.  Like a fully lit, empty parking lot at 3:00 a.m., our lights were performing no useful function in the moonlight on that mountain.  They simply were not needed.   This is often the case in our homes and communities.  Wasteful, useless light streams unabated into the environment from countless sources, bringing with it an array of negative effects.  To minimize the effects of light pollution on humans and wildlife, and reduce the damage to our views of the night sky, we all need to assess which lights are truly needed and which are not.   When deciding whether to install a new light or to keep an existing fixture, there are a few things to consider.

The first thing to ask yourself is whether the light has a clear purpose.  Two years ago, my wife and I bought our dream home in the foothills of Colorado.  It’s a beautiful place on an acre and a half, with great views of Mount Evans, a fourteen thousand foot peak just west of Denver.  When we moved in, I began to notice all the lights on our property.  They were EVERYWHERE.  The original owners were artists, and I can only guess that they were using the light for aesthetic purposes to highlight the beauty of their home.  Thankfully, this lighting system had been abandoned by the previous owners and none of the fixtures worked.  Still, during a short walk around our property, I counted over THIRTY outdoor lights, ranging from low bollards along the driveway to spotlights over the decks.  But one light in particular caught my eye.  In front of our house a small spotlight was strapped to the trunk of a good-sized Douglas Fir.  The light was pointing straight up!   Over the past two years, I have removed many of the fixtures and the maze of wiring connecting them, but I left this wayward light as a perfect example of a light with no purpose.

If the light in question exists for a reason, are there things you can do to meet the same objective without lighting?  At my house, a natural walkway between a small parking area and our front door was lit with several low bollards. The lights clearly helped prevent people walking on the path from tripping on small rocks and tree roots. However, the walkway was rarely used as most people walked down our paved driveway at night.  We decided to remove the walkway and the bollards.  Remove the need and you can remove the light.

Generally, lights are installed to boost our ability to complete a task under low-light conditions. Nighttime tasks that are often enhanced by lighting include walking and wayfinding, negotiating stairs, entering and leaving buildings, driving, reading, and identifying things (e.g. our car in a parking lot).    Adding light to these situations can improve our ability to complete these important tasks safely and efficiently.  However, the benefit of adding light isn’t always related to illumination; in some cases it’s more about increasing contrast.  Visual contrast sensitivity is the ability to distinguish between an object and its background or to detect differences between similar shades of light and dark. If you increase the visual contrast in a scene, you can reduce or even eliminate the need for additional light. This can be accomplished in a number of ways including changing surface colors or textures.  To increase contrast on outdoor stairs, treads can be outlined in reflective tape or similar  material.  Door knobs and lock mechanisms can be painted lighter colors and walkways can be constructed using lighter colored surfaces.  Always look first for ways to increase contrast without installing a light.  Another option that eliminates the need for additional lighting is to encourage the use of personal lights.  These days almost everyone is carrying a personal flashlight in their pocket or purse in the form of a cell phone app.  In some cases, it’s much more efficient and cost effective to let people use their own light.  Of course, there are circumstances where outdoor lighting is necessary.  However, we should always consider other methods of illumination before we install permanent lighting fixtures.

By 6:00 a.m., we were standing on top of Mount Elbert at an elevation of 14,439 feet, the highest point in Colorado.  We enjoyed the warmth of dawn and watched as the first few rays of the sun reflected off the golden ribbon of the Arkansas River far below.  Hiking at night, may not be for everyone, but it helps us understand the purpose and usefulness of light as a tool for completing our tasks and goals efficiently.  It also demonstrates that nature and human physiology often combine to allow us to function effectively and safely in dark conditions without added light.   Our first task when considering outdoor lighting is to assess whether it is truly needed and whether it has a clear purpose.  If it doesn’t, don’t install it.  If it’s already there, remove it.  This is the first important step for ensuring that naturally dark conditions and starry night skies will exist for the enjoyment of our children, grandchildren, and generations to come.