The human-centric focus on the impact of artificial light has overshadowed its effects on animals and plants
By Jane Slade
Darkness is disappearing from the face of the Earth, blinding wildlife in the light. Since life began, the Earth’s rotation has created cyclical darkness by which living things evolved, tuning instincts and behaviors over millennia. Each night, darkness fell upon the Earth without fail, bringing with it a moment of rest and reflection, and a philosophy of understanding one’s place in the universe by looking up at the night’s sky. There is a subtle yet profound loss without this moment of reflection, and much of the discussion of dark-sky awareness has focused on this loss. Yet, there is something much more urgent happening than the absence of philosophy and reflection.
The loss of darkness has also inhibited the sensory experience of wildlife, changing not only the behavior of species, but also how species interact with one another. Whether it is a tree’s misunderstanding of how soon winter is to prepare for dormancy1 or a bird’s inability to see the night’s sky for astronavigation, artificial light is creating a language for animals and plants that is impossible to interpret.
For wildlife, light has been the environmental factor that has remained constant and therefore became the great indicator of time and space. In comparison to the ebb and flow of other factors such as weather patterns and climate, light’s precision was incomparable. In the last 100 years, however, the original ways to perceive time and space through light have become distorted, altering perception of the natural daylight cycle and obscuring the view of the night’s sky. This has created blindness for all living creatures on Earth, with unknowable impact.
A BROADER VIEW OF CIRCADIAN
In recent years, we have begun to understand that the impact of light upon humans is more than just visual. Light is deeply connected to circadian functions through biochemical reactions in the body. While we have begun to wrestle with the benefits and drawbacks of artificial light for humans, this human-centered focus has overshadowed the understanding of the impact of artificial light upon the environment. Circadian rhythms are also present in plants and animals, and in many ways are more important for wildlife than for humans. For wildlife, staying in rhythm with the environment is the first line of defense for survival.
This article will review a sampling of species that are impacted by light pollution. It should be noted, however, that due to biodiversity and the interdependence of all living things, there is no living creature on Earth that is not impacted by light pollution, either directly or indirectly. It should also be noted that sea turtles will not be discussed here, as this species’ battle with light pollution has received much attention. The impact of light pollution is far more widespread than just a single species, and awareness must be shifted to a larger scope of understanding.
As humans, the sky was our first screen, revealing constantly changing data about time, season, location, direction and the Earth’s atmospheric conditions. In modern times, we now have other ways of collecting information about the world, whether it’s the phone we keep in our pockets, the television or social behaviors. For animals, the sky is an irreplaceable and unique source of information that speaks directly to instincts developed over lifetimes of evolution. Here are a few examples of impacts among species:
Simply put, light outside of natural daylight cycles is a form of pollution for all living creatures, whether directly or indirectly. Yet, if the power went out right this second, light pollution would immediately go away. That is to say, of all forms of environmental pollution, light pollution may, in fact, be one of the easiest to solve.
As lighting controls begin to become a mandatory component of lighting designs, it bears mentioning that the very name, lighting controls, points to the fact that we have not been in control of lighting up until this point. This is evidenced by the many satellite images of Earth showing enormous amounts of light spill into the sky. Design for the environment has always been difficult to navigate within a cost-driven economy where human comfort and safety are central concepts. Yet controls offer a way to utilize one lighting installation in multiple ways, therefore adding in the ability to bring in environmental lighting concepts easily.
There are other innovations that will contribute to reducing the effect of artificial light upon the environment, such as Dark-Sky compliant fixtures, color tuning and fixture optics. As the lighting industry emerges from its nascence of utilizing older, inefficient sources such as metal halide and fluorescent lamps, we are coming into a new era of LEDs. The tiny size of LED chips offers unparalleled optics and the ability to direct light exactly where we want it.
Lastly, as LEDs refine color techniques, including tuning and designing with specific wavelengths, we may just find ourselves with abilities in lighting design that we have never had before, such as biologically supporting well-being by fine-tuning wavelengths for specific needs across species. The future of lighting is not just about human health, but rather about the wellbeing of all beings in order to best support biodiversity and interdependence.