By Prof Corrie Schoeman
Light pollution is the presence of unwanted, inappropriate, or excessive artificial lighting, and is one of the fastest and most drastic changes humans have made to the earth’s environment. Sources of light pollution include street lights, security lights that light up buildings and their surroundings, advertising and display lighting, and floodlights used to illuminate sport fields and places of entertainment. Light pollution has increased about 10% each year over the past decade, and is currently turning night into day in 80% of the world. Near cities, cloudy skies are now hundreds or even thousands of times brighter than they were 200 years ago. Today, most people can no longer see the true beauty of the night sky from their homes. Even some of the brightest stars are lost in the glare of light pollution from towns, cities, roads and industrial areas. For many people, the sight of the Milky Way stretching across the night sky is a childhood memory; a new generation is growing up without ever seeing our own galaxy. We are only now beginning to learn what far-reaching effects light pollution has had on the nocturnal biology and ecology of organisms.
The day to night cycle is an essential part of nature, alerting animals when to emerge to hunt, forage, migrate, and mate. When artificial light at night disrupts those natural night cues, wildlife are negatively impacted. For example, it skews the circadian rhythms of songbirds and mice, interferes with amphibian and firefly reproduction, confuses sea turtle hatchlings searching for the moon, throws migrating birds and butterflies off course, and renders many nocturnal insects such as moths more vulnerable to predation. Even plants are affected by light pollution – it disrupts their seasonal rhythms, their ability to sense and react to natural light, and their fragile relationship with pollinators. Many species aren’t directly affected by light pollution, but they can be indirectly impacted. For example, bees aren’t attracted to light, but they’re negatively affected by light pollution because the plants they pollinate aren’t as stimulated to produce pollen by nocturnal pollinators who are driven away by artificial lights. Indeed, there is increasing evidence from scientific research that light pollution will have devastating impacts on biodiversity if nothing is done urgently. In humans, increased light at night lowers melatonin production, which results in sleep deprivation, fatigue, headaches, stress, anxiety, depression, and other health problems including diabetes and breast cancer. Perhaps most importantly to people, light pollution takes away the enjoyment and awe of the immensity of space, and the spiritual experience of discovering our place in nature.
Unlike air or water pollution, light pollution can be eliminated immediately. However, lighting decisions are made by millions of people, therefore to make real progress you have to get all those people on board. Some communities are showing what those social changes might look like. For example, the entire island community of New Zealand is currently working to meet light pollution standards, the Pacific island country of Niue was the first country to become a certified International Dark Sky Sanctuary in 2020, in 2019, France imposed a new law setting strict limits for how and when light shines at night, and in the USA, the National Audubon Society’s Lights Out program encourages cities from San Francisco to New York to reduce their nighttime lights during periods when migratory birds are passing through.
Advocating for large-scale policy changes on light pollution can feel daunting, therefore best is to start small. For Simbithi residents, reducing light pollution can be as simple as turning off the lights, installing motion sensors that limit when lights are on, shielding your lighting so it’s aimed downward rather than up into the sky, or adding dimmers that reduce the light coming from a single bulb. Although energy efficient LEW light bulbs are cheaper and longer-lasting than their incandescent predecessors, they produce a short-wave blue-tinted light that attracts more insects and birds and disrupts circadian rhythm in mammals. Replacing blue LEW bulbs with warm LEDs (<3000K) or yellow-tinted filters, for example, can significantly minimize these impacts. Moreover, if light in the neighbourhood is bothering you or you think it’s a problem, it’s worth complaining to the relevant local authorities. Often, there are simple fixes that don’t cost very much money and can solve the problem effectively. Many of the solutions saves money by reducing electricity usage, hence it is a win-win for everyone.
Artificial light that serves no purpose is a waste of money and energy, and ultimately increases carbon emissions. Reducing light pollution therefore not only benefits energy consumers financially, but helps mitigate climate change by reducing the emissions associated with energy production. The last decade has seen a global movement to establish “dark-sky places”. These are typically protected areas with clear management plans to minimise light pollution; have night skies below a certain level of skyglow; host public engagement and outreach activities related to the night; support ecological integrity; and engage with local citizens, companies, and management agencies to foster good outdoor lighting practices. Perhaps it is time eco-estates such as Simbithi become part of this drive to maintain the health of our incredible biodiversity, and increase our quality of life by restoring our access to the wonder of beautiful night skies.
