The Death of Night: Astronomers and Environmentalists Fight to Save Dark Skies
In the era of 24/7 artificial light, real darkness is hard to find. But not only stargazers are affected -- light pollution also threatens animals and even entire ecosystems.
A small drama unfolds in the skies over Germany and other industrialized countries every evening. The sun sets, and yet it remains light -- so light, in fact, that one can hardly see anything.
Even before the sun goes down, Germans are already switching on billions of light bulbs, fluorescent tubes and headlights. Office towers shimmer, streets are illuminated and billboards are brightly lit, as are churches, castles and ruins. Airports, nuclear power plants and football fields are bathed in blazingly bright light. Despite climate change, the economic crisis and high electricity prices, thousands upon thousands of new light sources are constantly being added to the mix. As a result, Germany is getting brighter, practically from one night to the next.
People living in Germany no longer react with awe when they happen to look up at the sky on a clear night. Nothing twinkles in the heavens anymore, and most Germans are only familiar with the majestic appearance of the Milky Way from trips abroad.
One of the most prominent stars in the night sky at the moment is Aldebaran, a red giant which is the brightest celestial body in the constellation of Taurus. The Andromeda galaxy should also be visible without a telescope. But who notices anymore? City children, who are growing up under a hazy orange night sky, can barely name three celestial bodies anymore: the sun, the moon and possibly Venus, also known as the evening star.
For thousands of years, the stars served mankind as a natural navigation system. They were also the inspiration for calendars, stories, legends, myths and religions. The changing night sky was always part of the landscape and at the same time part of culture. But then industrialized society pushed a button, and the firmament was switched off. The 24-hour day had arrived, and the night sky disintegrated like a coral reef destroyed by tourists.
Fighting the Loss of Night
But now a new movement is taking shape worldwide in opposition to the misuse of artificial light. Stargazers, environmentalists, light engineers, cultural anthropologists and doctors specializing in the treatment of sleep disorders all want to put an end to the dictatorship of eternal light. Light pollution is a rapidly growing environmental problem, but it is also one that could be solved relatively easily. In many cases, all it takes is goodwill and a few little tricks.
Some countries have already passed laws and regulations to control light pollution. Slovenia is a pioneer in Europe. There, cities and towns are now required to reduce their light emissions. In addition, artificial lights must shine in such a way that their light beams do not rise above the horizon. This spells the end of the "skybeam" searchlights much loved by nightclub operators.
Germany has been less active on the photon front, although German scientists did recently embark on the battle against light pollution. Under the leadership of the Berlin-based Leibniz Institute of Freshwater Ecology and Inland Fisheries (IGB), more than two dozen scientists from various disciplines will study the effects of light pollution on plants, animals and human beings, as well as what to do about it.
For eons, all life on earth has been shaped by the constant cycle of day and night. But in many places, night has been lost. This loss, says IGB director Klement Tockner, "entails a dramatic reduction in biodiversity." According to Tockner, the adverse effects are especially noticeable in bodies of water, where "the light shining in promotes algae growth and changes the food web throughout an entire lake."
The United Nations Education, Scientific and Cultural Organization (UNESCO) has proclaimed 2009 the International Year of Astronomy, marking the 400th anniversary of Galileo's invention of the telescope, and in doing so has officially declared war on light pollution as the enemy of astronomers. Under today's conditions, the Italian astronomer might as well have thrown away his telescope, because it would have been useless.
Protecting the Dark
For years, the US-based International Dark-Sky Association has fought to stop the adverse effects of light pollution. The organization has awarded the title "International Dark Sky Park" to two regions to date, one in Utah and one in Pennsylvania. This year the designation will likely also be awarded to a region in Europe for the first time, but only after intensive study.
At least one public nature reserve will be named as an oasis of darkness, based on its efforts to protect its night sky as vehemently as its owls and other aspects of the natural world. Brightly illuminated Germany has no candidates up for the award. England, on the other hand, has two favorites, the Exmoor National Park near Bristol and the Peak District National Park near Manchester. Admittedly neither are as dark as an oil rig in the Pacific -- which ranks as a class one "excellent dark-sky site" on the Bortle nine-point scale of night-time illumination -- but they are hilly enough to be relatively well-protected against incoming urban light. France also has a strong contender in the form of the mountainous region surrounding the Pic du Midi Observatory in the Pyrenees.
The candidates hope to use their potential status as dark sky parks to promote "astro-tourism." The British are particularly fond of the stars, so much so that astronomy magazines enjoy large circulations. In the future, anyone looking up at the sky on clear nights in these stargazer parks can expect to see satellites flying by or, depending on the season, the constellation of Orion. Though barely visible in cities today, in dark-sky regions Orion appears as a three-dimensional giant made up of dozens or even hundreds of twinkling components.
The park administrations must demonstrate that they are committed to the dark-sky designation. This includes cleaning up their light, which means eliminating streetlights and other light sources, or at least modifying them so that they shine downward, rather than to the side or upward. Though technically straightforward, the necessary effort and expense can be considerable, particularly as European national parks, unlike those in the United States, are often inhabited. All it takes is a few uncooperative residents unwilling to give up the floodlights on their barn and the candidate's prospects become as good as nonexistent.
Steve Owens, an astronomer from Glasgow and the coordinator of all British Dark Sky Park applications, is nonetheless optimistic. "In a few years," he says, "there could easily be 10 or even 15 of these parks in Great Britain." There is considerable willingness among park managers to recognize the night sky as a core constituent of nature requiring conservation, says Owens.
Owens, for his part, doesn't need dark-sky parks to see the stars. Thinly populated Scotland is still considered one of Europe's darkest regions. "All I have to do is drive for two hours into the Highlands, and I'm surrounded by complete darkness," says Owens. "This is unique. Elsewhere in Europe, what we usually have are small pockets of darkness. Here the darkness is everywhere." In the summer, however, the northern night sky is so strongly illuminated by the midsummer sun that Owens could even read a newspaper on a moonless night.
In Germany, a truly dark sky is nowhere to be found. Andreas Hänel, an astronomer in the northwestern city of Osnabrück and head of a German dark-sky association, recently went looking for a place to view the stars in the eastern Alps. He was unable to find even a single spot that has remained completely protected from light smog.
He is also pessimistic when it comes to the northeastern state of Mecklenburg-Western Pomerania. On satellite images, it occasionally appears as a refuge of darkness, but Hänel fears that the lights of civilization can even be seen there, glowing on the horizon.
A Menacing Glare
These issues raise a fundamental question for people in populated areas: How much light do people need? For decades Belgium, with its passion for brightly lit highways, took an extreme position when it came to artificial light. But even Belgium has now revised its approach. For the past two years, almost all highway lights have been shut off shortly after midnight. Many feared a sharp increase in the number of accidents, but that has not happened. In fact, motorists drive more slowly and cautiously in the dark.
For traffic experts, street lighting in areas other than risk zones, such as intersections, is an ineffective means of improving safety. In fact, because such lighting is often installed incorrectly, the resulting glare can cause more harm than good.
The issues are similar for many downtown and residential areas. Although people feel safer not having to walk around in the dark, there has been little change in levels of risk in places where lighting was switched off. For instance, four years ago, the city of Rheine in northwestern Germany started shutting off most of its streetlights on weekdays between 1:00 and 3:30 a.m. The move saves electricity, money and CO2 emissions -- and yet there has been no increase in street crime.
But light at night does have deadly consequences for many animals. Some species, no longer able to find shelter in the dark, are more likely to be eaten by predators.
Billions of insects die on streetlights each year or in the webs of the spiders that live on these lights in unnaturally large quantities. Many birds flying at night become confused by the light smog and collide with brightly lit high-rise buildings. Light-sensitive frogs stop their mating activity, thereby producing fewer or no offspring. Freshly hatched sea turtles crawl toward the light on streets instead of into the ocean. Salamanders remain hidden longer than usual, because of insufficient darkness, which deprives them of the time they need to search for food.
People are also adversely affected by the elimination of night, but in less direct ways. Electric light, rather than a natural rhythm, now determines the waking and sleeping times of individuals. Artificial light disturbs the hormonal balance, especially the production of the sleeping hormone melatonin, which also helps block the growth of cancer cells.
Studies have shown that women who often work night shifts have an elevated risk of contracting breast cancer. Some scientists have even concluded that an excessively bright sleeping environment, such as one in which streetlights shine into the bedroom, increases the risk of cancer.
"We know about the adverse health effects of noise," says Hänel, "but with light we are just beginning to understand the connection."
For this reason, Hänel believes that the establishment of large dark zones in Germany is long overdue. They could be set up in places like the Harz Mountains, the Bavarian Forest and Mecklenburg-Western Pomerania. "We could save energy and money, and improve our quality of life at the same time."
Translated from the German by Christopher Sultan
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