We all deserve to see the stars – how light pollution affects our health

Artificial light at night has a detrimental effect on the natural world, and our physical and emotional well-being

The wonders of the night sky are revealed when we experience real darkness. EPA

“Lights please, lights please, turn off the lights”  these are the lyrics of a hip-hop track that often pops into my head while I’m driving through Abu Dhabi after dark. On one of my typical nocturnal routes, I might pass office blocks with every floor still illuminated, floodlit construction sites and the houses of newlyweds decked out in decorative fairy lights. Add to this thousands of street lamps, and it matters very little whether there is a full moon or a waxing crescent – the night is always bright.

At one of my previous homes, with my own indoor lights off, I could open my curtains at night and literally read a book by the spotlights of my neighbour’s villa. I had to invest in blackout curtains to ensure any chance of a good night’s sleep.

Beyond my own personal grievances, however, the issue of artificial light at night is a genuine and growing environmental concern.

"Skyglow" sounds like something delightful, but it is actually the name given to light pollution, the diffuse luminescence in the night sky not attributable to the moon or the stars. According to the World Atlas of Artificial Night Sky Brightness, around 80 per cent of the world's human population now live beneath skyglow. Many of us rarely, if ever, experience a naturally dark night.

Unlike many other countries, it is possible to gain some respite in the UAE. If you have ever been camping deep in the nation's desert, you will know what an Arabian night sky really looks like. The stars shine brighter for one thing, and way more of them are visible.  The first time I saw the night sky in such a setting, I was mesmerised.  It was like gazing at a beautiful face that I knew well but had somehow never really seen before.

Beyond the aesthetics, the darker side of artificial light pollution is that it interferes with our ecosystems in complex ways that we are only slowly beginning to appreciate. For example, 40 per cent of the world’s insect species face extinction, and some of this loss is attributed to artificial night light making insects more vulnerable to predation. Some might dismiss the loss of a few creepy crawlies as trivial. However, it is worth reflecting on the words of the Pulitzer-prize-winning biologist, E O Wilson.  “If insects were to vanish, the environment would collapse into chaos,” he has said.

It is not only insects that are affected. Another recent discovery is that artificial night light stresses amphibians too. Ultimately, this means fewer frogs and toads are making it to maturity. Again, this is likely to have a knock-on effect further up the food chain. Perhaps one of the saddest examples, though, is the impact that artificial light has on baby sea turtles. Each year tens of thousands of newly hatched turtles are misguided and disorientated by our artificial light sources. Rather than following the light of the moon to the sea, they end up stranded on land, squished by cars or picked off by predators. Light pollution is one of the main reasons hatchlings don’t make it to adulthood.

Beyond the animal kingdom, light pollution can also take its toll on humans. Always fond of a good acronym, scientists now talk about Alan (artificial light at night) posing a significant threat to our health.

Frequently, when we go to sleep, even if we have blackout curtains, our bedrooms are filled with small artificial lights blinking away at us – TV standbys, phones, internet routers. This artificial light at night – Alan, if we must – is thought to disrupt the production of the hormone melatonin, and is associated with an increased risk of numerous health complaints, including diabetes, breast cancer, prostate cancer and sleeping disorders.

There is also a link between light at night and mental health. For a long time, we referred to mental-health problems as lunacy, and those who experienced them as lunatics – words derived from the idea that the moon, especially the full moon, triggered insanity. The notion of a link between the moon and mental health is not as wild as it might sound. In pre-industrialised societies, when nights were dark, a full moon might prove particularly disruptive to sleep patterns, triggering psychological disorders in the vulnerable.

It is now well established that circadian rhythm disruption, messing with the body clock, can trigger psychological problems. This is especially true for those prone to episodes of depression and mania.

In short, artificial light at night is damaging. So much so that the American Medical Association published a public report titled Light Pollution: Adverse Health Effects of Night-time Lighting.

The full health and environmental implications of Alan are still emerging. However, we know enough to understand that taking action is in our best interest and the interest of the planet. Thankfully, unlike air and water pollution, light pollution is entirely reversible. The solution is relatively simple too: keep lighting to a necessary minimum. The night sky is far more beautiful with the lights off.

Justin Thomas is a professor of psychology at Zayed University