Light pollution is not just a waste of money, argues astronomer Darren Baskill. Badly designed lighting, he continues, harms the environment and our health, and deprives millions of people of the right to enjoy the beauty of the night sky.
When people think of light pollution, they mostly think of beleaguered astronomers.
The orange haze of night-time light pollution, which also hides the stars from view, is the most visible evidence of wasted light. But what is truly astronomical is the economic, environmental and human cost of light pollution. Light pollution is wasted artificial light that ends up where it is neither necessary nor wanted. Most light fittings waste a large proportion of the light they produce. More than 300 megawatts of light is wasted into the sky by Britain’s street lights alone, at an annual cost of around £100m ($190m).
Even the most modern street lighting systems direct light away from the road and towards the sky. This makes the night sky brighter and the roads darker, which is a double blow for a cycling astronomer, for example.
It takes a medium-sized lignite-fired power station to generate all this wasted energy, adding millions of tonnes of carbon dioxide to the atmosphere every year. If we also count inefficient lighting in homes, businesses, churches and sports facilities, we begin to grasp the sheer scale of the waste.
Light pollution is also growing rapidly. According to the Campaign to Protect Rural England (CPRE), light pollution in the UK rose by 24% between 1993 and 2000, making Great Britain the third most light-polluted country in Europe.
False Security
Our desire for lighting at night in a 24-hour society seemingly justifies any amount of wasted light, yet the consequences are sometimes tragic. In the Oxford area, a person was killed when a floodlight from a bar blinded a driver. In Australia, poor design of the direction of an airport’s lighting caused a fatal crash. Intrusive lighting can also cause stress with health consequences, heart problems and even suicidal thoughts.
Exposure to light at night may also increase the risk of cancer. Dr Chris Idzikowski, director of the Sleep Assessment and Advisory Service, says: “[This] could lead to disrupted sleep patterns and hyperactivity, and may have a negative effect on a child’s health.” Light pollution also has a devastating effect on wildlife, disrupting feeding and breeding cycles. A study in Toronto found more than 2,000 migratory birds of 89 different species dead beneath over-lit skyscrapers. Bats and various insects are also adversely affected.
The most common justification for lighting is safety, together with the naive belief that “the more light, the better”. Visit any supermarket in New York and you will see the shelves full of 150W, 300W and even 500W floodlights. Yet the website of the Department of Homeland Security states specifically that in most cases this kind of lighting is not appropriate.
Consider that the Smalls lighthouse (20 miles off the coast of Wales) has a 35-watt lamp that produces a beam visible for 21 miles, and you can see why. The irony is that such dazzling so-called “security lights” can in fact conceal criminal activity in their glare, and because they are often triggered by cats moving about at night, neighbours soon learn to ignore them.
Research on street lighting by the British Home Office revealed that brighter lighting does little to combat crime, since lighting helps everyone see better around them, criminals included.
Turning Down the Brightness
The government has introduced the Clean Neighbourhoods Act (2005), which aims to bring intrusive lighting under criminal law. Unfortunately, the Act includes a long list of unexplained exemptions. While a homeowner can be punished for installing indiscriminate lighting, a bus stop cannot. A growing number of badly lit buildings, especially churches, can also be exempted from control.
While some local councils understand the problem of light pollution, others make it worse. Stockport Council recently installed new street lighting systems that light homes five times more brightly than the recommended levels. Things are different in other countries. Light pollution laws exist in the Czech Republic, Italy, Chile and some parts of the US. In 2005, the city of Calgary finished replacing 37,500 street lights with more efficient ones, saving $2m (£0.9m) a year, which will pay back the replacement costs in just six years.
Elsewhere, such as in Rome, lighting levels are reduced after midnight, cutting costs by 40% at the same time, and in the US, Long Island’s energy management replaced all outdoor lighting systems with more efficient ones. All this shows that we can have light without light pollution. Make sure that the lighting at your home or office is directed only where it is needed and at the appropriate level, with no waste towards the sky or neighbouring homes. Walk around your lights and make sure they are not visible from beyond the area they are meant to cover.
The same goes for street lighting: dimming technology should be used wherever possible. England’s M65 motorway was fitted with such systems, cutting energy costs by 50% and also reducing visual difficulties for drivers.
These small steps will save significant amounts of energy and money, reduce carbon dioxide emissions, and improve the view of both the streets and the sky. While many people have heard of light pollution, few, unfortunately, make even a small effort to tackle it.
We all need lighting, astronomers included, but that need must not be used as an excuse for inefficiency on a vast scale. No one should have their right to see, explore and be inspired by the night sky called into question.
Dr Darren Baskill is an astrophysicist at the University of Leicester and works on the European space telescope mission XMM-Newton. He is also a member of the Campaign for Dark Skies, a group originally formed by amateur astronomers to encourage the use of efficient, appropriate lighting.
