“Red skies at night, sailor’s delight.” The old adage is taking on a new meaning as the world lights up, saying good-bye to the dark nights of the past. While some lighting is useful, other types are wasteful. On average, the latter costs Americans about $2 billion or 17 billion kilowatt-hours (KWH) of energy each year.
Light Pollution and Climate Change
The multitude of unnecessary and poorly directed light is a form of pollution, explains the World Health Organization. For every 1,000 KWH, it takes about 940 pounds of coal or 1.8 barrels of oil to supply the electricity. According to the New Jersey Astronomical Association, over 30 percent of outdoor lighting is misdirected into the sky, adding an absurd amount of greenhouse gases to the atmosphere.
These facts say nothing about the mercury emitted into the environment from the common dusk-to-dawn mercury vapor light. Sulfur dioxide and nitrous oxide are also released from fossil fuel combustion needlessly.
Light Pollution and Public Health
The human body relies on its circadian rhythms or biological clock to function properly, as does wildlife and plants. Artificial light can increase stress and negatively impact natural cycles. These effects can cause sleep disruptions, which can, in turn, increase the risk for obesity and related chronic health conditions.
Part of the reason may lie with effects on the production of melatonin hormone in the brain, which helps the body regulate sleep and wake cycles. The potential risks are so great the American Medical Association issued a warning against the health hazards of artificial light.
Changing Night Sky
The deluge of artificial light is causing the night sky to appear red rather than black, especially in urban areas. It can affect animals’ circadian rhythms, just as they do in people. In wildlife, this can be manifest in disturbances in natural predator-prey relationships and breeding cycles.
The loss of the night due to light pollution has widespread consequences. This form of pollution is especially insidious because of itself, it is not commonly thought of as harmful. The reality is that misdirected light can have serious health consequences that are more frightening than not being able to see the Milky Way or thousands of stars.