It’s time for light pollution to play a bigger part in the energy conservation equation.

As an advocate for responsible outdoor lighting in my fast-growing Central Texas county as well as statewide with DarkSky Texas, I’ve noticed that too many energy conservation and efficiency programs pay little attention to the waste that derives from unnecessary use of light.  There is a common perception that light pollution is an astronomy issue having to do with the view of the stars, and not enough realization that improper or unnecessary use of artificial light not only wastes energy but also harms virtually all forms of living beings.

The International Dark-Sky Association estimates that at least 35 percent of all outdoor lighting in the United States alone is wasted, often because it was improperly shielded or poorly aimed.

That’s one reason why Scientific American published an article on light pollution last fall with the headline, “The Sky Needs Its ‘Silent Spring’ Moment,” referring to Rachel Carson’s 1962 book that was a trigger for the environmental movement.  Too many people do business as usual or choose the cheaper options.

Globally, the impact of light pollution is increasing at a startling rate.  The journal Science reported in January that an analysis of citizen science data collected through the Globe at Night program found skyglow increasing faster than previously recorded.  Skyglow is the artificial brightness of the night sky caused by light pollution, diminishing the view of the stars

The report based on data from 2011 to 2022 found that “In Europe and North America, where most of the participating citizen scientists live, skyglow has been increasing by 6.5% and 10.4% per year, respectively.”  Citizen science data points from other parts of the world were too scarce for conclusions, but the team conducting the study suspected that skyglow could be increasing at even higher rates elsewhere.

In a startling example, the study explains that a person born when they could see 250 stars in the sky would see only 100 by the time he or she is 18.  Imagine how much energy it takes to obscure so much sky.  

How often have you driven by an empty parking lot late at night with its light fixtures glaring, or seen houses with outdoor lights left on throughout the night?  Presumably this is because of fear of darkness, even though energy wasting, bright and glaring nights may actually hinder safety.

Each light matters, from the bulb or bulbs framing a residential door to those from a skyscraper.  Certainly, indoor light should be considered, especially lights left on all night long in empty office buildings.

IDA, soon to be known as DarkSky International, and the Illuminating Engineering Society have teamed up to publish the Five Lighting Principles for Responsible Outdoor Lighting.  It’s not enough to simply point light downward; all five principles should be considered to be effective.

They state that light should be useful, targeted, low level, controlled and of a warmer color.

By useful, it means that light should be used only when needed, with a clear purpose.  Turn a light on to walk a dog outside, turn it off when you are back inside.

By targeted, use direct light so it falls only where it is needed.  Shielding and careful aiming target the direction of the light beam so that it points downward and does not spill beyond where it is needed.

By low level, light should be no brighter than necessary.  The lowest level required should be the choice.

By controlled, use light only when it is needed.  Timers or motion detectors help make sure that light is available when needed, dimmed when possible and turned off when not needed.

And by color, warmer color lights should be used where possible.  The cooler choices in many LED streetlights for example, are in the shorter blue violet length on the spectrum instead of toward the yellow. That’s why we often see so much glare from unshielded or even shielded streetlights and spotlights that use cool white LEDs or compact fluorescents.

Light trespass and glare can be minimized with proper light design.

In our local group as well as DarkSky Texas, we’re working to counteract the conventional view that more people and more buildings automatically means more light and more light pollution.  The often used reminder is that light pollution is perhaps the easiest environmental concern to solve, if only light could be used responsibly..

We are working to protect and restore our night skies, increase safety, reduce energy cost and waste, and enhance the health of people, plants and animals.