LET THERE BE LIGHT?

A ‘Incandescent light bulbs lit the 20th century; the 21st will be Jit by LED lamps.’ So stated the Nobel Prize Committee on awarding the 2014 prize for physics to the inventors of light-emitting diodes (LEDs).

Around the world, LED systems are replacing most kinds of conventional lighting since they use about half the electricity, and the US Department of Energy expects LEDs to account for 74% of US lighting sales by 2030.

However, with lower running costs, LEDs may be left on longer, or installed in places that were previously unlit. Historically, when there has been an improvement in lighting technology, far more outdoor illumination has occurred. Furthermore, many LEDs are brighter than other lights, and they produce a blue-wavelength light that animals misinterpret as the dawn.

According to the American Medical Association, there has been a noticeable rise in obesity, diabetes, cancer, and cardiovascular disease in people like shift workers exposed to too much artificial light of any kind. It is likely more pervasive LEDs will contribute to a further rise.

B In some cities, a brown haze of industrial pollution prevents enjoyment of the night sky; in others, a yellow haze from lighting has the same effect, and it is thought that almost 70% of people can no longer see the Milky Way.

When a small earthquake disabled power plants in Los Angeles a few years ago, the director of the Griffith Observatory was bombarded with phone calls by locals who reported an unusual phenomenon they thought was caused by the quake – a brilliantly illuminated night sky, in which around 7,000 stars were visible. In fact, this was just an ordinary starry night, seldom seen in LA due to light pollution!

Certainly, light pollution makes professional astronomy difficult, but it also endangers humans’ age-old connection to the stars. It is conceivable that children who do not experience a truly starry night may not speculate about the universe, nor may they learn about nocturnal creatures.

C Excessive illumination impacts upon the nocturnal world. Around 30% of vertebrates and over 60% of invertebrates are nocturnal; many of the remainders are crepuscular – most active at dawn and dusk. Night lighting, hundreds of thousands of times greater than its natural level, has drastically reduced insect, bird, bat, lizard, frog, turtle, and fish life, with even dairy cows producing less milk in brightly-lit sheds.

Night lighting has a vacuum-cleaner effect on insects, particularly moths, drawing them from as far away as 122 metres. As insects play an important role in pollination, and in providing food for birds, their destruction is a grave concern. Using low-pressure sodium-vapour lamps or UV-filtered bulbs would reduce insect mortality, but an alternative light source does not help amphibians: fogs exposed to any night light experience altered feeding and mating behaviour, making them easy prey.

Furthermore, birds and insects use the sun, the moon, and the stars to navigate. It is estimated that around 500 million migratory birds are killed each year by collisions with brightly-lit structures, like skyscrapers or radio towers. In Toronto, Canada, the Fatal Light Awareness Program educates building owners about reducing such deaths by darkening their buildings at the peak of the migratory season. Still, over 1,500 birds may be killed within one night when this does not happen.

Non-migratory birds are also adversely affected by light pollution – sleep is difficult, and waking up only occurs when the sun has overpowered artificial lighting, resulting in the birds’ being too late to catch insects.

Leatherback turtles, which have lived on Earth for over 150 million years, are now endangered as their hatchlings are meant to follow light reflected from the moon and stars to go from their sandy nests to the sea. Instead, they follow street lamps or hotel lights, resulting in death by dehydration, predation, or accidents, since they wander onto the road in the opposite direction from the sea.

D Currently, eight percent of all energy generated in the US is dedicated to public outdoor lighting, and much evidence shows that lighting and energy use are growing at around four percent a year, exceeding population growth. In some newly-industrialised countries, lighting use is rising by 20%. Unfortunately, as the developing world urbanises, it also lights up brightly, rather than opting for sustainability.

E There are several organisations devoted to restoring the night sky: one is the International Dark-Sky Association (IDA), based in Arizona, US. The IDA draws attention to the hazards of light pollution and works with manufacturers, planners, legislators, and citizens to encourage lighting only what is necessary when necessary.

With 58 chapters in sixteen countries, the IDA has been the driving force behind the establishment of nine world reserves, most recently the 1,720-square-kilometre Rhon Biosphere Reserve in Germany. IDA campaigns have also reduced street lighting in several US states and changed national legislation in Italy.

F Except in some parks and observatory zones, the IDA does not defend complete darkness, acknowledging that urban areas operate around the clock. For transport, lighting is particularly important. Nonetheless, there is an appreciable difference between harsh, glaring lights and those that illuminate the ground without streaming into the sky. The US Department of Transportation recently conducted research into highway safety and found that a highway lit well only at interchanges was as safe as one lit along its entire length. In addition, reflective signage and strategic white paint improved safety more than adding lights

Research by the US Department of Justice showed that outdoor lighting may not deter crime. Its only real benefit is in citizens’ perceptions: lighting reduces the fear of crime, not crime itself. Indeed, bright lights may compromise the safety, as they make victims and property more visible.

The IDA recommends that where streetlights stay on all night, they have a lower lumen rating, or are controlled with dimmers; and, that they point downwards, or are fitted with directional metal shields. For private dwellings, low-lumen nightlights should be activated only when motion is detected.

G It is not merely the firefly, the fruit bat, or the fog that suffers from light pollution – many human beings no longer experience filling stars or any but the brightest stars, nor consequently ponder their own place in the universe. Hopefully, prize-winning LED lights will be modified and used circumspectly to return to us all the splendour of the night sky.