The use of artificial lights at night contributes to an alarming increase in light pollution that affects places all over the world, findings of a new study published in the journal Science Advances on Nov. 22 revealed.

Planet Earth Getting Brighter At Night

Christopher Kyba, from the GFZ German Research Centre for Geosciences, and colleagues used data from the Suomi National Polar-orbiting Partnership, or Suomi NPP, to study surface light pollution and found that Earth is getting brighter and brighter.

The researchers reported that the artificially lit surface of the planet at night rose by 2 percent per year over the past four years.

"We use the first-ever calibrated satellite radiometer designed for night lights to show that from 2012 to 2016, Earth's artificially lit outdoor area grew by 2.2 percent per year, with a total radiance growth of 1.8 percent per year. Continuously lit areas brightened at a rate of 2.2 percent per year," the researchers wrote in their study.

Effects Of Light Pollution On Human Health

As nighttime on the planet becomes brighter and brighter, researchers raised concern over the threats that this poses to humans, animals, and the whole ecosystem. Earlier studies have already identified some of the unwanted effects of light pollution, particularly on human health.

A 2016 study found that light pollution can interfere with sleep patterns. Researchers found that people who live in urban areas with strong outdoor lighting were 6 percent more likely to have less than six hours of rest at night compared with those who live in areas with less intense lights at night. Those exposed to more nighttime lighting are also more likely to experience fatigue, and have higher odds of suffering from impaired functioning and extreme drowsiness.

A Harvard study also found a link between outdoor light at night and increased breast cancer risk. The researchers said that exposure to light at night may lead to reduced level of the hormone melatonin that influences the body's circadian rhythms, which in turn can lead to increased odds of developing breast cancer.

"In our modern industrialized society, artificial lighting is nearly ubiquitous. Our results suggest that this widespread exposure to outdoor lights during nighttime hours could represent a novel risk factor for breast cancer," said study researcher Peter James.

The disruption of the circadian rhythm, which may arise because of ill-timed electric lighting especially at night, has also been linked to mood disorders, obesity, diabetes, and certain cancers.

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