The Tunnel at the End of the Light

Recognize the picture above? From old photographs? Your vision of the night sky? Well not if you are among the 85%plus of Americans who live in or near urban concentrations. Odds are that you will never see this many stars anywhere near a city, much less in one, even in towns with virtually no air pollution to speak of. It’s why so many of the red states have it all over those urban concentrations in the blue states. It’s what the sky is supposed to look like at night. It just might be why all those campers are so darned happy!

It’s called light pollution, and it has been creeping up on humanity for a long time now. “Thanks to electric lights, outdoor lighting grew at a rate of 3% to 6% annually in the second half of the 20th century. Though this has benefited human productivity and safety, it has come with a dark side: The night is no longer dark enough.

“Half of Europe and a quarter of North America have experienced seriously modified light-dark cycles, the study authors wrote, calling it a ‘widespread loss of the night.’… This light pollution can have serious consequences for living things, which have evolved in accordance with a natural day-night cycle, in which the only major sources of light at night would have been the moon or more intermittent sources such as volcanoes, lightning, wildfires or auroras.

“‘From an evolutionary perspective, now, artificial light at night is a very new stressor,’ [said Franz Holker of the Leibniz-Institute of Freshwater Ecology and Inland Fisheries, author of a recent study on this phenomenon]. ‘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.’

“That’s a big problem, given that 30% of vertebrates and more than 60% of invertebrates are nocturnal, he pointed out. It can affect plants and even microbes. It also could be harming vital interactions between species, such as the pollination of plants and spreading of seeds by key nocturnal creatures… ‘It threatens biodiversity through changed night habits, such as reproduction or migration patterns, of many different species: insects, amphibians, fish, birds, bats and other animals,’ he said.

“Humans are affected by artificial light too because there are certain physiological processes that happen during the day and certain ones that happen at 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.” Los Angeles Times, November 26^th.

OK, we aren’t going to turn off tons of lights to avoid light pollution, although there’s a lot to be said for saving electricity and reducing our carbon footprint accordingly. But this is still a big problem. “The researchers [from NASA and the National Oceanic and Atmospheric Administration] studied data from the month of October in each year from 2012 to 2016. They found that over that time, Earth’s artificially lit outdoor surface grew by 2.2% each year, and the total radiance grew by 1.8% a year. On top of that, the outdoor areas that already had been lit when the study started in 2012 also brightened by 2.2% a year.

“The fastest growth took place in countries in developing regions, such as Asia, Africa and South America. Countries that already were brightly lit, such as the United States and Spain, appeared stable. A small number of war-ravaged countries such as Yemen and Syria saw a drop in their artificially lit levels… But even in those brightly lit countries that appeared stable, light levels are probably still on the rise, the scientists said.

“That’s because many well-lit cities have been replacing yellow-orange sodium lights with energy-saving LED lights. Those sodium lights put out a small amount of infrared radiation, which would have made them look brighter to VIIRS. The white-toned LED lights have more blue wavelengths, which VIIRS cannot see. The combination of losing the infrared signal and not being able to see the blue wavelengths means that VIIRS registers these areas as dimmer, even though they may be brighter than they were before.

“‘That means that this measurement that we’re reporting is a lower bound on how Earth’s light is increasing,’ said study lead Christopher Kyba of the German Research Center for Geosciences. ‘And in fact, the true increase that a human being would perceive is actually larger than what we report here.’

“Researchers had long suspected that the introduction of LEDs would mean less energy used for lighting, he said. The problem is this also made lighting cheaper… ‘Whenever you make lights more efficient, you just don’t save energy,’ Kyba said. ‘What happens instead is that people put more lights up.’… The blue light in those LEDs also are particularly disruptive for many nocturnal animals, researchers said.

“There are some possible solutions, Kyba said, such as using LEDs that don’t have a blue component. There also are ways to position and manage existing light sources — say, the lamps in a parking lot — so that they are not as bright but still are effective.” LA Times. But for the rest of us, it is amazing what a cool, quiet room with blackout curtains can do for a good night’s sleep. Still, switch off what you don’t need on… and dim lights or use LEDs when you can.

I’m Peter Dekom, and I hope I didn’t make too light of this subject matter.