The scourge of industry pollution and its effect on global warming, the raping of our natural resources, and the threat of urbanisation and poaching on our dwindling species diversity are hugely topical in today’s age.
However, one form of pollution is often overlooked and its influence is slowly spreading across the globe, causing havoc within ecosystems for wildlife and people alike. For millennia, humankind has found ways to cast light into the shadows, and illuminate the world. But we have come a long way from our ancestors huddling around campfire. With 8 billion people in the world, the majority of whom live squashed together in population centres, it is no wonder that the sanctity of darkness is now under real threat.
Light pollution is measured on the Bortle Scale from 1 to 9. 1 denotes an area completely devoid of artificial light such as deserts, while 9 is excessively polluted and synonymous with population centres like cities. Eighty percent of the population live under light polluted skies, including a staggering ninety-nine percent of all Americans and Europeans.
Light pollution includes the following categories: Glare – excessive lighting that can cause visual discomfort. Light is scattered in the eyes which can reduce contrast and be dangerous, especially when driving. Light Trespass – light falling where it is not needed or intended. Artificial light from street lights for example can illuminate bedroom windows, causing annoyance and sleep difficulties. Light Clutter – bright, confusing, and excessive grouping of light sources. These are typically found in areas like malls and entertainment venues.
Many studies have shown that dark skies are synonymous with health. Our bodies, just like all organisms, have adapted to a world with periodic phases of light and dark. This is known as a ‘circadian rhythm’, and it governs both physical and mental cycles. The Earth has been spinning since its conception, our parent star rising and setting with every turn. For 4,5 billion years this cycle has dominated, and every life form on this planet, from single celled organisms to dinosaurs and humans have evolved in parallel. Our technological success, and subsequent reliance, has rendered this ancient pattern defunct, and the disruption can be seen in all life, manifesting itself both physically and psychologically.
The circadian rhythm in humans is governed by the hormone, melatonin, which is created in response to darkness. It triggers the body to sleep and enter a resting phase which comes with a whole host of beneficial, and necessary, effects. With excessive lighting and the artificial light from screens such as phones, tablets, TV’s and computers, melatonin creation is stunted and can lead to a variety of health issues such as insomnia, depression, stress, anxiety, and weight gain. Some studies have even suggested a link between melatonin deficiency and cancer.
But it is not just humans that suffer at the hands of light pollution. Nocturnal predators rely on the anonymity afforded by the cover of darkness. Many animals navigate by the stars. Various marine mammals use the stars to help them traverse the vast oceans, as they provide the only reference point from which to take a bearing. Every year thousands of sea turtle hatchlings perish, heading inland instead of towards the water, mistaking skyglow from human habitation for the ocean’s vast horizon.
Experiments have shown that migratory birds use the motion of the night sky to guide themselves on their great, cross-continental journeys, and the innumerable swathes of insects rely on moonlight to orientate their flight. Let us not forget the lovable dung beetle who relies on the Milky Way to plot its course during moonless nights!
Insects make up the bulk of food for countless other animals, and the disruption of artificial light has a major effect on this food source, including driving their predators towards lit areas. Why insects are so attracted to outside lights is not fully understood, but many species have what is known as a ‘dorsal light response’, meaning that they fly orthogonally to the light (at 90°), keeping the Moon and stars above them. This is why they tend to spiral towards outside lights as opposed to simply landing on them.
Without action, this scourge will get worse, especially as the population and its reliance on technology increases. So, what can be done? As with most issues like this, the answer starts at home. Turning off unnecessary lights, ensuring lights are appropriately shielded and pointed downwards, and using ‘warm’ coloured lights are very simple fixes. This also helps with saving money and reducing the carbon footprint. If everyone adopted this approach, particularly commercial outfits, the improvement would be monumental.
In South Africa, the !Ae!Hai Kalahari Heritage Park is recognised as an International Dark Sky Sanctuary, and next door in Namibia, the Namib Rand Nature Reserve is proclaimed an International Dark Sky Reserve. These areas attract a great deal of tourism on the back of these accolades, with people from all over the world flocking to the area to take advantage of the dark skies for both recreational and research purposes.
Here in Hoedspruit, with the Kruger National Park on our doorstep, we should be aiming for similar standards. Safari lodges and surrounding areas should lead by example and can very simply improve the standard of lighting. In addition to a greatly enhanced natural experience, it will ultimately save money in terms of wasted electricity (particularly important in these load-shedding afflicted times!), not to mention the benefits to the wildlife these areas seek to preserve. People visit these areas to enjoy the natural beauty and rich species diversity, and to be immersed in the natural world. After all, what is more immersive that sitting under a starry African night sky, listening to the haunting whoop of distant hyena or the ‘bass baritone’ roar of a patrolling lion.
Anyone wishing for more information should have a look at the IDA website at www.darksky.org.
See Celestial Events SA advert for contact details
