WHAT IS LIGHT POLLUTION?

-By Prudhvi Raj Madhu

Most environmental pollution on Earth comes from humans and their inventions. Take, for example, the automobile or that human-made material, plastic. Today, automobile emissions are a major source of air pollution, and plastics fill our ocean, creating a significant health hazard to marine animals. 

And what about the electric lightbulb, thought to be one of the greatest human inventions of all time? Electric light can be a beautiful thing, guiding us home when the sun goes down, keeping us safe. But, too much of a good thing has started to negatively impact the environment. Light pollution, the excessive or inappropriate use of outdoor artificial light, is affecting human health, wildlife behavior, and our ability to observe stars and other celestial objects.

How Bad is Light Pollution?

With much of the Earth’s population living under light-polluted skies, over lighting is an international concern. If you live in an urban or suburban area all you have to do to see this type of pollution is go outside at night and look up at the sky.

According to the 2016 groundbreaking World Atlas of Artificial Night Sky Brightness 1, 80% of the world’s population lives under skyglow. 

Before and during the 2003 Northeast blackout, a massive power outage that affected 55 million people. Photo by of Todd Carlson

If you want to find out how bad light pollution is where you live, use this  NASA Blue Marble Navigator 2 for a bird’s eye view of the lights in your town.

Effects of Light Pollution

Environment: The International Dark-Sky Association 3 (IDA), a non-profit organisation that raises awareness of light pollution, estimates that excessive nighttime lighting releases more than 12 million tons of carbon dioxide, the most serious greenhouse gas, into the atmosphere each year. It would take nearly 702 million trees to absorb the carbon dioxide produced by wasted light.

Light pollution may also contribute to other forms of pollution. According to a 2010 study by the National Oceanic and Atmospheric Association, photopollution increases air pollution by suppressing a naturally occurring radical that cleans the air at night. Nitrate radical, a form of nitrogen oxide, breaks down vehicle and factory emissions at night. The nightly process prevents the emissions from becoming smog, ozone pollution, or other harmful irritants. The process only takes place at night because sunlight destroys nitrate radicals. However, artificial lights from buildings, cars, and streetlights, although 10,000 times dimmer than sunlight, also affect nitrate radical and slow down the cleansing process by 7%. Artificial light also increases the chemicals for ozone pollution by 5%.

Energy: Wasted light results in energy waste. A 2007 IDA study estimated that 30% of all light emitted by public outdoor light fixtures is wasted, which amounts to 22 Terawatt Hours (TWh)/year of wasted electrical energy. This is equivalent to the following:

  • About 3.6 million tons of coal per year
  • About 12.9 million barrels of oil per year

The total amount of wasted electrical energy each year is enough to illuminate over 11 million homes and power over 777,000 cars.

Wildlife: Luminous pollution affects the feeding, sleeping, mating, and migration cycles of all wildlife. Wildlife can also experience disorientation of time when there is too much artificial light at night.

  • Mammals – Mammals such as bats, raccoons, coyotes, deer, and moose can experience difficulty foraging for food at night due to over illumination. They risk exposure to natural predators and increased mortality due to night vision impairment. They also experience a decline in reproduction that leads to a shrinking population.
  • Birds – Birds such as owls and nighthawks use moonlight and starlight to hunt and migrate at night. Artificial lights sources can overwhelm natural light sources, causing birds to be drawn to or fixated on the artificial lights. This results in birds deviating from their intended migration route, flying until they experience exhaustion and collapse

Astronomy: Light pollution alters our view of the sky and stars, but no group of people is more affected by this phenomenon than astronomers. Light spill and sky glow interferes with astronomical equipment, and makes viewing faint celestial bodies difficult even with the aid of a telescope.

Astronomy is one of the oldest sciences in human history, and has made countless contributions to technology, economy and society with applications like personal computers, communication satellites, mobile phones, Global Positioning Systems (GPS), solar panels, and Magnetic Resonance (MRI) scanners.

Today, astronomy helps us determine the Sun’s effect on Earth’s climate, and identify any potential threats to Earth from space. In order to conduct observation and research, astronomers require dark skies.

Humans: Humans, like plants and wildlife, are regulated by circadian rhythms, the physical, mental and behavioral changes that occur in a 24-hour cycle. The circadian clock regulates physiologic activities such as brain wave patterns, hormone production, and cell regulation. The rhythms respond to the light and darkness around an organism. Disrupting these rhythms can result in a variety of health problems, including sleep disorders, anxiety, depression, diabetes, cancer (particularly breast and prostate cancer), cardiovascular disease, immunological disorders, and obesity.

Melatonin, the naturally occurring hormone that regulates the sleep and wake cycle, is acutely affected by light pollution. The hormone is activated by darkness and repressed by light. Melatonin deficiency can result in anxiety and mood disorders, insomnia, and elevated estrogen/progesterone ratio.

In 2009, the American Medical Association (AMA) unanimously supported the reduction of light pollution, and advocated the development of energy-efficient outdoor lighting to reduce glare and energy waste.

How can you help ?

Take Action Now: We can’t protect the night from light pollution without you! And we have some great simple ideas for you to take action right now.

  1. Inspect the lighting around your home:

Poor lighting not only creates glare and light pollution but also wastes enormous amounts of energy and money. Take a few moments to inspect your property for inefficient, poorly installed and unnecessary outdoor lighting. Learn how by visiting Residential/Business Lighting page 4 

  1. Talk to your friends, family, and neighbors:

You can be a powerful dark sky advocate for your neighborhood, your city, and even your state and country. Solving the light pollution problem involves raising awareness of the issue so that people are empowered to make better decisions as consumers, voters and community members. 

  1. Advocate for a light pollution laws in your town:

Unfortunately, there are not many laws in India recognizing light pollution. We have to  ask the state government and pollution control board to draft norms for light pollution in the cities,

New Delhi, Telangana, Maharashtra, Karnataka and Uttar Pradesh experienced an increase in “very high light pollution intensity” from 1993 to 2013. West Bengal, Gujarat and Tamil Nadu witnessed a remarkable change from low to high light pollution.5

References

  1. https://www.darksky.org/80-of-world-population-lives-under-skyglow-new-study-finds/
  2. http://www.blue-marble.de/nightlights/2012
  3. https://www.darksky.org/
  4. https://www.darksky.org/our-work/lighting/lighting-for-citizens/residentialbusiness-lighting/
  5. https://www.sciencedirect.com/science/article/abs/pii/S2212095518303717
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