The Issues: Lights

 

Leslie Peltier, a well known amateur astronomer and author once wrote, "The moon and the stars no longer come to the farm. The farmer has exchanged his birthright in them for the wattage of his all-night sun. His children will never know the blessed dark of night."

sustainable TablePeltier was referring to light pollution, or the excessive use of light. Large industrial dairies are often heavily lit 24 hours a day—making them visible for miles in the nighttime sky. Their light can blot out clear views of the rural nighttime sky, distract drivers passing by on neighboring roads, spill unwanted light onto the property of neighboring homes, and reduce property values by making the area less attractive. Most importantly, light pollution is also a major waste of energy, especially considering that many factory farms use lights 24 hours a day.

Undesired Effects

But light pollution is not just annoying and wasteful - it’s also hazardous to the health of farm animals, human beings and even entire ecosystems. Since life evolved around natural patterns of light and dark, artificial light can alter animal and plant behavior. For instance, light pollution has been found to disrupt the behavior of birds, aquatic animals and insects, it can increase algae in nearby lakes and ponds, and it effects seasonal patterns of plants and trees. ii

The heavy use of lights in dairy free stall barns and drylots can also lead to heath problems for both cows and human beings. Operators of industrial dairies often keep lights on for eighteen or more hours a day in the free stalls and dry lots where cows are confined. Increasing the number of hours a cow is exposed to light is a way to manipulate the animal’s internal clock and increase the amount of milk she produces. That’s because exposure to light suppresses the secretion of a hormone called melatonin.  When there’s less melatonin in the blood, that affects production of other important hormones, like insulin growth factor-I (IGF-I), which triggers the production of extra milk. In order to reap maximum production from cattle herds, 18 hour-a-day lighting is now standard practice on large factory dairy farms. iii

The problem is that melatonin— for cows, for wildlife, and for humans and all other mammals—is a powerful and critical hormone. For instance, melatonin levels in the body can help determine when puberty begins. Studies have found that heifer calves exposed to artificially long periods of light grow faster and reach puberty faster. iv

Melatonin is also an important antioxidant that helps maintain the body’s immune system. Exposing cows to 18 hours of lighting in free stalls can therefore contribute to a vicious cycle: it increases a cow’s chances of becoming sick, which in turn increases the chances that the dairy operator will treat the animal with antibiotics and anti-virals, which then risk getting passed on to humans in milk (or beef, if the cow is slaughtered.) And as antibiotics get overused, dangerous bacteria begin to mutate and become resistant to certain drugs. v

Light pollution may also pose more direct risks to humans. Night light doesn’t just suppress melatonin in cows, but in humans, too. In addition to strengthening your immune system, melatonin also reduces your cholesterol and blood pressure, benefits that are lessened with exposure to light at night. Recent studies suggest that there may be a link between lower levels of melatonin in women and the risk of breast cancer, and some experts believe that light pollution should be taken more seriously as a public health threat. vi

What you can do

  • Hold  CAFOs (confined animal feeding operations) accountable.
    If you live near a CAFO, talk to your neighbors and others in the community also affected by light and other forms of pollution. Share information that you can use to lodge a complaint. Many local governments have nuisance laws and environmental laws that govern the operations of CAFOs. Get to know the people on your local zoning commission — they can be great allies.
  • Buy sustainable dairy products.
    Support farmers that raise their animals without damaging the night time environment. Visit your local Farmer’s Market where you can ask the farmer directly about the farm’s light usage.
  • Use the Eat Well Guide to find farms, stores, restaurants, and bed & breakfasts offering sustainable dairy and other animal products in your area.

Did you know?

  • The human body produces melatonin – a chemical that helps protect your body against cancer – while in darkness. According to two studies published last year in the Journal of the National Cancer Institute, if the light coming in your bedroom window at night is at least as strong as a streetlight, it may be detrimental to your health. vii
  • Some groups view dark skies as a natural resource akin to an old growth forest or wetlands, worthy of protecting for its role in ecological balance.
  • Nocturnal birds use the moon and stars for navigation during their bi-annual migrations, which can be disturbed by artificial light. viii

For more information

  • International Dark-Sky Association: The mission of the International Dark-Sky Association (IDA) is “to preserve and protect the nighttime environment and our heritage of dark skies through quality outdoor lighting.”
  • Use Sustainable Table’s Shop Sustainable section to learn more about where to get food from local farms, and get the questions to ask the farmers you meet there.

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