The unfortunate side effect of LED lighting

Steep, unhealthy rise in use of artificial lights at night across India, shows ...

Our night lights are eating away night sky! Lifestyle to blame?

Due to energy and cost-saving benefits of these artificial lighting, more and more people are switching to artificial lights across the world, increasing outdoor lighting on a global scale.

There are two separate factors to be considered when looking at light pollution - the total outdoor area that is artificially lit, and the brightness of those lit areas. The total radiance of lit areas over the country also increased by 7.1% per year or 31.6% during the same period.The study is important because light pollution, which is caused by excessive, misdirected or obtrusive outdoor lighting, has adverse effects on humans, plants and animals.The analysis, led by GFZ German Research Centre for Geoscience, using data from Visible/Infrared Imager Radiometer Suite (VIIRS), showed that globally, the increase in artificial lighting over the Earth's surface has increased by 2.2% every year - 9% from 2012 to 2016 - with a 1.8% growth in total radiance.

Much of the increase is concentrated in the Middle East and Asia.

Scientists used images from one of the USA's polar-orbiting satellites to study the changes in nighttime light over time. "Continuously lit areas brightened at a rate of 2.2 percent per year", according to the study.

The trend shows no sign of relenting.

"The fact that the median country's 15 percent increase in lighting from 2012 to 2016 almost matched the median 13 percent increase in GDP suggests that outdoor light use remains subject to a large rebound effect on the global scale", according to the study.

The Arizona-based International Dark-Sky Association's executive director J. Scott Feierabend said the study "validates the message IDA has communicated for years" about the hazards of artificial night lights.

LED lights offer the advantage of lower energy consumption, making the switch to using the technology an easy decision.

"The fact that we did not see the country get darker means that there were new lights in other places, or else brighter lights that were in some other cities installed that make up for this difference", said Kyba.

The shift from incandescents to LEDs has been directly observable from space.

But as LED lights become more efficient and cheaper people have chosen to use more of them, rather than holding on to their energy savings - a process known as the "rebound effect". Last year, the American Medical Association issued a warning about health risks associated with this type of light. Then, filtered the data to check night brightness for the month of October between 2012 and 2016.

Bright nighttime lighting only started becoming widespread about 100 years ago, meaning we have little idea how humans or other species adapt to it at an evolutionary level.

Ecologist Franz Holker of Germany's Leibniz-Institute for Freshwater Ecology and Inland Fisheries (IGB) said light pollution has ecological consequences, with natural light cycles disrupted by artificial light introduced into the nighttime environment.

Perhaps the most effective way of solving the light pollution problem, however, is to spread awareness. Studies have shown, for instance, that judicious use of low-level LED lighting can reduce light pollution without compromising peoples' sense of safety. "Transitions to LED lighting greatly increase this 'skyglow, ' because the clear sky predominantly scatters short-wavelength light", the study explains.

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