Why I light up my garden for more than half the year

On a particularly grey, rain-swept evening in Drumchapel, Glasgow, where the encroaching winter darkness typically casts a somber spell, a sudden, almost defiant explosion of colour pierces the gloom. It’s not a fireworks display, nor a distant carnival, but the radiant spectacle of Sandra Lee Myles’ garden. For over half the year, her modest plot transforms into a wonderland of twinkling LEDs, glowing inflatables, and meticulously arranged festive figures. From the street, the effect is immediate: an involuntary smile, a gasp of delight, a momentary reprieve from the mundane. Sandra, a local legend, has lost count of the myriad decorations she owns, each one a brushstroke in her ever-expanding canvas of light, a beacon drawing curious glances and warm conversations from passersby. Her garden isn’t just decorated; it’s alive, pulsating with an energy that transcends mere aesthetics, sparking a deeper inquiry into our complex relationship with light.

This dazzling display, however enchanting, prompts a scientific contemplation that stretches far beyond the immediate joy it brings. The very act of illuminating our surroundings, whether a single garden or an entire city, has profound and often unseen consequences for the natural world. Scientists refer to this phenomenon as Artificial Light At Night, or ALAN, and its reach is now global, altering fundamental ecological processes. Our planet, once governed by the ancient rhythm of day and night, is increasingly bathed in an unnatural glow, disrupting the delicate balance that life has evolved over millennia. Nocturnal animals, from tiny insects to large mammals, rely on darkness for navigation, foraging, and reproduction. Migratory birds, using celestial cues, become disoriented by city lights, veering off course or colliding with illuminated structures. The very fabric of ecosystems, from predator-prey dynamics to plant pollination, is subtly, yet significantly, altered by the pervasive presence of artificial light.

Consider the humble moth, drawn irresistibly to a porch light. While seemingly innocuous, this attraction can be a death trap, pulling them away from foraging or mating opportunities, making them easy prey, and ultimately impacting entire food webs. Research has shown that even low levels of artificial light can suppress melatonin production in various species, including humans, interfering with sleep cycles and overall health. For plants, ALAN can alter flowering times, disrupt dormancy, and affect the timing of leaf senescence, confusing their internal clocks and impacting their interaction with pollinators. The blue-rich light emitted by many modern LEDs, while energy-efficient, is particularly problematic, as it penetrates deeper into the atmosphere and has a more pronounced biological effect on many organisms. Sandra’s garden, while a source of community cheer, becomes a microcosm, a tangible representation of a worldwide phenomenon, forcing us to consider the intricate dance between human innovation, aesthetic desire, and the profound ecological ripples we inadvertently create.

Beyond the immediate ecological concerns, the proliferation of artificial light speaks to a deeper human impulse. For centuries, light has been a symbol of safety, progress, and celebration. From the flickering hearths of ancient settlements to the gas lamps of Victorian cities and the electric grids of our modern metropolises, humanity has sought to push back the darkness. In colder climates, like Drumchapel, where winter days are short and often bleak, the psychological benefits of light cannot be overstated. Sandra’s vibrant display combats the gloom, fostering a sense of community, wonder, and shared festivity. It’s a powerful antidote to Seasonal Affective Disorder, a communal act of defiance against the natural world’s more austere moods. This duality – light as a source of comfort and joy versus light as an environmental disruptor – is a defining characteristic of our age. Urban planners grapple with balancing public safety and visibility with the need to minimize light pollution. Astronomers lament the loss of the night sky, now obscured by a pervasive glow that extends hundreds of miles from city centers. The discussion around ALAN is not merely about turning off lights; it’s about thoughtful, responsible illumination, understanding its spectrum, direction, and intensity, and finding harmony between human needs and ecological integrity.

For those of us who feel the pull of Sandra’s illuminated garden, yet also recognize the scientific implications of our brightly lit world, there are profound experiences to be sought out. To truly grasp the impact of artificial light, one must seek its antithesis: genuine darkness. Travel to a certified International Dark Sky Place, such as the Galloway Forest Park in Scotland, or further afield to the Aoraki Mackenzie International Dark Sky Reserve in New Zealand, or the vast stretches of Big Bend National Park in Texas. Here, under skies unmarred by urban glow, the Milky Way arches overhead in breathtaking clarity, revealing a cosmic spectacle that most modern humans have never witnessed. It is a humbling experience, connecting us to the universe in a way that no city light ever could, offering a profound appreciation for the natural rhythm of light and shadow that once governed all life on Earth.

Conversely, to experience the communal joy and artistic potential of light in a more controlled and celebrated manner, consider visiting one of the world’s renowned light festivals. Lyon’s Fête des Lumières, Berlin’s Festival of Lights, or Vivid Sydney transform entire cities into galleries of light art, using cutting-edge technology to create dazzling, temporary installations. These events showcase humanity’s ingenuity and creativity, demonstrating how light can be used not just for utility, but for profound aesthetic and social impact. They echo the spirit of Sandra Lee Myles’ garden on a grand scale, celebrating light as a source of wonder, community, and shared human experience, albeit for a limited duration and with a conscious design towards artistic rather than pervasive illumination. Both extremes – the pristine darkness of a dark sky preserve and the vibrant spectacle of a light festival – offer unique perspectives on our relationship with light, inviting us to contemplate its power, its beauty, and its often-overlooked consequences. They encourage us to find a balance, to appreciate the brilliance of human innovation while safeguarding the delicate equilibrium of the natural world.