Published: Sun, November 26, 2017
Sci-tech | By Javier West

Earth's nights are getting brighter due to artificial lighting

Earth's nights are getting brighter due to artificial lighting

It also could be harming vital interactions between species, such as the pollination of plants and spreading of seeds by key nocturnal creatures.

The ecosystem is also at risk, with the changes impacting the migration and reproduction patterns of birds, fish, amphibians, insects and bats.

Humans are impacted by artificial light too because there are certain physiological processes that happen during the day and certain ones that happen in the darkness of night - and they often work against each other, Holker said. That's why working against our biological day-night clocks (for example, as night-shift workers must) can result in many kinds of issues, from depression-like symptoms to obesity and diabetes.

Artificial light at night is a major contributor in causing light pollution, both in quantity and luminosity influencing places all over the world.

"We can say with fairly high confidence even though we didn't measure in the satellite an increase in these countries, they are almost certainly increasing in brightness in terms of how human beings would perceive the light", Kyba said. Their time series comprises the years 2012 to 2016. For another, transient, unintended light - such as wildfires in the western United States and especially in Australia during the four-year observation period - could throw off the results, with some areas appearing as if they had actually gotten darker over time, but only because the blazes had at last been extinguished. There is also a continuous growth in lightings in Asia, Africa, and South America. Researchers noted a few rare declines in war-torn places like Syria and Yemen; while Italy, the Netherlands, Spain, and the U.S., which make up some of the world's brightest areas, remained relatively stable. A small number of war-ravaged countries such as Yemen and Syria saw a drop in their artificially lit levels.

The American Medical Association a year ago said that white LED lights are increasingly suspected of impacting humans, estimating they have "five times greater impact on circadian sleep rhythms than conventional street lamps".

Shanghai, the most populous city in the world!

Chris Kyba, a physicist at the GFZ, explained how cheaper, whiter LEDs have led to increased usage, "People keep installing more and more lights".

Researchers had long suspected that the introduction of LEDs would mean less energy used for lighting, he said. Moving to outdoor LED lighting was supposed to help the problem, but it's made matters worse.

"Whenever you make lights more efficient, you just don't save energy", Kyba said. "The problem is that light has been introduced in places, times and intensities at which it does not naturally occur, and many organisms have had no chance to adapt to this new stressor".

Worldwide there has been thrust towards more power- and cost-effective lighting such as LEDs, but this has instantly bestowed to a shocking expansion in light pollution, the researchers presume.

There are some possible solutions, Kyba said, such as using LEDs that don't have a blue component.

Those who study light pollution are also looking at ways to improve lighting to make it more practical, including full cut-off lighting, more diffuse lighting and less blue light.

On a global or national scale, all this wasted light is expensive, he says: "It costs a lot of money to radiate that light into space and it's not doing anybody any good".

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