Shining a light on a far too bright and wasteful world

The Eiffel Tower will be dimmed come July as France tackles light pollution by curbing unnecessary use at night. John Elk / Getty Images

The City of Light dimmed? It's true. Thanks to a new law, not only Paris but all of France will see its lighting level reduced, beginning this July.

Window lighting in commercial buildings and the lights on building facades will be turned off after 1am, and interior lighting in offices will be off an hour after the last employee departs.

The new law promises to reduce carbon emissions and save energy - the annual equivalent of 750,000 households' worth. Most significant is its potential to turn the tide against light pollution by changing attitudes about our unnecessary overuse of light at night.

In almost every city, suburb and town in the United States, the streets, parking lots, petrol stations, and commercial and public buildings are lit through the night.

Over recent decades, the growth of this pollution has been relentless, yet slow enough that most of us haven't noticed. Parking lots and service stations, for example, are now often 10 times brighter than they were just 20 years ago, and light pollution continues to grow at an estimated 6 per cent every year.

The cost of all this light, monetary and otherwise, is high. The connections to sleep disorders, cancer, diabetes and other disease are serious enough that the American Medical Association has declared its support for light-pollution control efforts.

Every ecosystem on Earth is both nocturnal as well as diurnal, and light destroys habitat just as easily as any bulldozer can. And when eight out of 10 children born in America today will never see the Milky Way, we have even lost the stars.

The usual justification for these costs is that we need all this light for safety and security. This simply isn't true.

No one doubts that artificial light can reduce the risks of being out at night, and no one is saying that we ought to exist in the dark. But increasingly, police, doctors, astronomers, economists, business leaders, communities and now the French government agree that we should reduce the light we use, and that too much brightness at night actually reduces our safety and security. Bright lights may make us feel safer. Alone, however, they don't actually make us safer.

The research bears this out. In 2008, PG&E Corporation, the San Francisco-based energy company, reviewed the research and found "either that there is no link between lighting and crime, or that any link is too subtle or complex to have been evident in the data".

Others are even more to the point. The Australian astronomer Barry Clark went so far as to conclude that "advocating lighting for crime prevention is like advocating use of a flammable liquid to try to put out a fire".

Our own eyes tell the same story. Too much light at night actually blinds us with "disability glare" - something middle-aged and elderly drivers know all too well - and bright, unshielded lights make it impossible to see past them to where criminals might hide.

The next time you face a bright streetlight, block it with your hand and notice how much better you can see the area beneath and beyond the light.

Numerous villages, towns and cities in Europe and the US have initiated programmes to shut off streetlights for at least part of the night.

European cities such as Berlin and Copenhagen already have much lower levels of light than their US counterparts, and even some major American cities, such as Tucson, have strict lighting ordinances that require a level of light that most Americans would consider dim.

None of these towns and cities has reported related increases in crime.

The new French law is to be applauded, not only for what it may do to save energy and reduce carbon emissions, but also for what it may help us to understand. True safety and security at night comes from making smart decisions, being aware of our surroundings and using lighting wisely.

If the City of Light can do it, why shouldn't the rest of us?

Paul Bogard, who teaches creative nonfiction at James Madison University in Virginia, is the author of The End of Night: Searching for Natural Darkness in an Age of Artificial Light

* Bloomberg News