On a semi-clear night, an observer with fairly good vision should be able to see over 7,000 stars. But that spectacular sight requires darkness, an increasingly rare condition in our modern society.
A cloud of light hovers above most of the United States, nearly all of Europe, and all of Japan. Light pollution is said to be the worst in Hong Kong, where unlike other major cities like London, Frankfurt, Sydney, and Shanghai, there are no laws to control external lighting. In Tsim Sha Tsui, an urban area in southern Kowloon, Hong Kong, the night sky is trapped in a state of perpetual dawn, appearing 1,200 times brighter than normal.
Electricity forms the backbone of our modern society. City lights are in part a celebration of our power and achievements, and in pragmatic terms, streetlights are vital to our collective safety. We must pause, however, to think about what all that light really means and how it is damaging our world in significant ways.
Wildlife is the first to suffer the effects of rampant light pollution. The cycle of night and day is critical in telling animals when to carry out vital life functions like when to eat, sleep, and reproduce. Unnatural light patterns can cause significant behavioral changes, and as a result of increasing light pollution, many species of birds, like the Bewick swan in England, have altered their migration departures, arriving at their destinations in weather that is no longer suitable for mating. Others become confused by the brilliance of cities and crash into buildings. The European lesser horseshoe bat simply began to vanish after streetlights were installed.
Sea turtle hatchlings rely on the light of the moon to guide them from where they’ve hatched on the beach down to the water. Light pollution causes them to crawl in the wrong direction, and they can become stranded and die. In Florida alone, hatchling losses number in the hundreds of thousands every year.
Like other species in the animal kingdom, we as humans are not immune to the effects of light pollution. Excessive light at night impedes the production of one hormone, melatonin. Melatonin is critical in immune functions, metabolism, and our endocrine system. When its levels are disrupted, our circadian rhythms are thrown out of balance, which can cause sleep deprivation as well as a whole slew of problems that are linked to sleep like hypertension, poor metabolism, obesity, type II diabetes, heart disease, and heart attacks. Melatonin also naturally impedes cancer cell growth, and its depletion is connected to increased cancer risk.
Light pollution is also linked to air pollution. Light breaks down and depletes levels of NO3, a nitrate radical that neutralizes other nitrogen oxides that contribute to smog. The nighttime is important for levels of NO3 to rebuild in order to prevent smog buildup. Higher light levels mean up to 7 percent less NO3, which can increase smog components by up to 5 percent.
Luckily, light pollution caused by bad lighting design is one of the easiest and most cost effective environmental issues to prevent. All the light shining upwards into the sky is solely energy wasted, and a waste of energy is also a waste of money. This helps motivate cities to use lower-watt bulbs, motion-sensor lighting, and directionally optimized light fixtures, or fixtures that shield the light from shining upwards unnecessarily.
States such as Maine, Connecticut, New Mexico, Arizona, and Texas have passed laws mandating that outdoor lights be properly shielded and have a limited luminosity. Some of these laws pertain to privately owned lights, whereas others apply to state highways. Statewide measures to regulate light pollution have been brought to Washington and Idaho governments as well, though they have not received enough support to pass yet. The movement is especially prevalent in Northwestern cities, where municipalities and counties, such as Ketchum, Hailey, and the Sun Valley in Idaho, have grouped together as the “Dark Sky Ordinance” and have pledged to dial back light waste. Ingram Organizations such as the International Dark-Sky Association are pushing for each Northwest state to establish one International Dark Sky Park. So far, Goldendale Observatory State Park in South Central Washington is the first to meet the requirements.
Fifty years ago, when light pollution was thought to only affect astronomers, Flagstaff Arizona began to regulate lights and has since been named the first International Dark Sky City. Since 2009, the United Nation’s Year of Astronomy, light pollution has received international attention and is now a widely acknowledged environmental issue. A growing international concern with light pollution has led to the growth of many NGO’s, such as the Light Pollution Awareness Group in Malta, political action, and individual improvement of private lighting.
The EU has launched a number of programs, such as GreenLight, to adopt efficient lighting systems. France passed new light pollution laws this summer, and now offices and shops are required to turn their lights off overnight. Some European cities, like Madrid and Florence, have passed legislation and made a conscious effort to keep the brightness below 100 times the standard dark night.
Last year in Hong Kong, where the night skies are 1,000 times brighter than globally accepted levels, major buildings along the Victoria Harbor turned off their lights to mark earth hour. In Tsim Sha Tsui, the number of individual complaints to the government about light pollution has risen from 9, in 2003, to 361, in 2011.
Just as we have the ability to outshine nature, putting on a spectacle of unnecessary lights that drown out the stars, we are also capable of using efficient, conscientious lighting. Beyond the significant and real environmental effects of light pollution, the psychological impact of losing our vision of the universe is especially distressing. It is worth considering what it means that we’ve chosen to block out the universe, the infinitely powerful force that has remained mostly untouched by humanity.