Residents of Fountain Hills, a small town near Phoenix, Arizona, fought against the night sky pollution to restore their Milky Way skies.
Light pollution is defined as the excessive or wasteful use of artificial light.
Light-emitting diodes (LEDs) -- which became commercially available in 2002 and rapidly gained popularity in offices, schools, and hospitals when their price dropped six years later — inadvertently fueled the surge in light pollution. As traditional light sources like halogen, fluorescent, mercury, and sodium vapor lamps have been phased out or banned, LEDs became the main source of lighting globally in 2019. Switching to LEDs has been lauded as a win-win decision. Not only are they cheap but they also consume a fraction of electricity compared to their traditional counterparts.
But as cheap LED installations became omnipresent, they increased light pollution. “People have been installing LEDs thinking they are making a positive change for the environment. But LEDs are a lot brighter than traditional light sources,” explains Ashley Wilson, director of conservation at the International Dark-Sky Association (IDA). “Despite being energy-efficient, they are increasing our energy consumption. No one expected this kind of backlash from switching to LEDs.”
Light pollution impacts the circadian rhythms of all living beings — the natural internal process that regulates the sleep–wake cycle.
Currently, more than 80 percent of the world lives under light-polluted skies. In the U.S. and Europe, that figure is above 99 percent.
According to the IDA, $3 billion worth of electricity is lost to skyglow every year in the U.S. alone — thanks to unnecessary and poorly designed outdoor lighting installations. Worse, the resulting light pollution has insidious impacts on humans and wildlife — in more ways than one.
Disrupting the brain’s clock
Light pollution impacts the circadian rhythms of all living beings—the natural internal process that regulates the sleep–wake cycle. Humans and other mammals have neurons in their retina called intrinsically photosensitive retinal ganglion cells (ipRGCs). These cells collect information about the visual world and directly influence the brain’s biological clock in the hypothalamus.
The ipRGCs are particularly sensitive to the blue light that LEDs emit at high levels, resulting in suppression of melatonin, a hormone that helps us sleep. A 2020 JAMA Psychiatry study detailed how teenagers who lived in areas with bright outdoor lighting at night went to bed late and slept less, which made them more prone to mood disorders and anxiety.
“Many people are skeptical when they are told something as ubiquitous as lights could have such profound impacts on public health,” says Gena Glickman, director of the Chronobiology, Light and Sleep Lab at Uniformed Services University. “But when the clock in our brains gets exposed to blue light at nighttime, it could result in a lot of negative consequences like impaired cognitive function and neuro-endocrine disturbances.”
In the last 12 years, several studies indicated that light pollution exposure is associated with obesity and diabetes in humans and animals alike. While researchers are still trying to understand the exact underlying mechanisms, they found that even one night of too much light exposure could negatively affect the metabolic system. Studies have linked light pollution to a higher risk of hormone-sensitive cancers like breast and prostate cancer. A 2017 study found that female nurses exposed to light pollution have a 14 percent higher risk of breast cancer. The World Health Organization (WHO) identified long-term night shiftwork as a probable cause of cancer.
“We ignore our biological need for a natural light and dark cycle. Our patterns of light exposure have consequently become different from what nature intended,” explains Glickman.
Circadian lighting systems, designed to match individuals’ circadian rhythms, might help. The Lighting Research Center at Rensselaer Polytechnic Institute developed LED light systems that mimic natural lighting fluxes, required for better sleep. In the morning the lights shine brightly as does the sun. After sunset, the system dims, once again mimicking nature, which boosts melatonin production. It can even be programmed to increase blue light indoors when clouds block sunlight’s path through windows. Studies have shown that such systems might help reduce sleep fragmentation and cognitive decline. People who spend most of their day indoors can benefit from such circadian mimics.
When Diane Turnshek moved to Pittsburgh, she found it almost impossible to see a clear night sky because the city’s countless lights created a bright dome of light called skyglow.
Diane Turnshek
Leading to better LEDs
Light pollution disrupts the travels of millions of migratory birds that begin their long-distance journeys after sunset but end up entrapped within the sky glow of cities, becoming disoriented. A 2017 study in Nature found that nocturnal pollinators like bees, moths, fireflies and bats visit 62 percent fewer plants in areas with artificial lights compared to dark areas.
“On an evolutionary timescale, LEDs have triggered huge changes in the Earth’s environment within a relative blink of an eye,” says Wilson, the director of IDA. “Plants and animals cannot adapt so fast. They have to fight to survive with their existing traits and abilities.”
But not all types of LEDs are inherently bad -- it all comes down to how much blue light they emit. During the day, the sun emits blue light waves. By sunset, red and orange light waves become predominant, stimulating melatonin production. LED’s artificial blue light, when shining at night, disrupts that. For some unknown reason, there are more bluer color LEDs made and sold.
“Communities install blue color temperature LEDs rather than redder color temperature LEDs because more of the blue ones are made; they are the status quo on the market,” says Michelle Wooten, an assistant professor of astronomy at the University of Alabama at Birmingham.
Most artificial outdoor light produced is wasted as human eyes do not use them to navigate their surroundings.
While astronomers and the IDA have been educating LED manufacturers about these nuances, policymakers struggle to keep up with the growing industry. But there are things they can do—such as requiring LEDs to include dimmers. “Most LED installations can be dimmed down. We need to make the dimmable drivers a mandatory requirement while selling LED lighting,” says Nancy Clanton, a lighting engineer, designer, and dark sky advocate.
Some lighting companies have been developing more sophisticated LED lights that help support melatonin production. Lighting engineers at Crossroads LLC and Nichia Corporation have been working on creating LEDs that produce more light in the red range. “We live in a wonderful age of technology that has given us these new LED designs which cut out blue wavelengths entirely for dark-sky friendly lighting purposes,” says Wooten.
Dimming the lights to see better
The IDA and advocates like Turnshek propose that communities turn off unnecessary outdoor lights. According to the Department of Energy, 99 percent of artificial outdoor light produced is wasted as human eyes do not use them to navigate their surroundings.
In recent years, major cities like Chicago, Austin, and Philadelphia adopted the “Lights Out” initiative encouraging communities to turn off unnecessary lights during birds’ peak migration seasons for 10 days at a time. “This poses an important question: if people can live without some lights for 10 days, why can’t they keep them turned off all year round,” says Wilson.
Most communities globally believe that keeping bright outdoor lights on all night increases security and prevents crime. But in her studies of street lights’ brightness levels in different parts of the US — from Alaska to California to Washington — Clanton found that people felt safe and could see clearly even at low or dim lighting levels.
Clanton and colleagues installed LEDs in a Seattle suburb that provided only 25 percent of lighting levels compared to what they used previously. The residents reported far better visibility because the new LEDs did not produce glare. “Visual contrast matters a lot more than lighting levels,” Clanton says. Additionally, motion sensor LEDs for outdoor lighting can go a long way in reducing light pollution.
Flipping a switch to preserve starry nights
Clanton has helped draft laws to reduce light pollution in at least 17 U.S. states. However, poor awareness of light pollution led to inadequate enforcement of these laws. Also, getting thousands of counties and municipalities within any state to comply with these regulations is a Herculean task, Turnshek points out.
Fountain Hills, a small town near Phoenix, Arizona, has rid itself of light pollution since 2018, thanks to the community's efforts to preserve dark skies.
Until LEDs became mainstream, Fountain Hills enjoyed starry skies despite its proximity to Phoenix. A mountain surrounding the town blocks most of the skyglow from the city.
“Light pollution became an issue in Fountain Hills over the years because we were not taking new LED technologies into account. Our town’s lighting code was antiquated and out-of-date,” says Vicky Derksen, a resident who is also a part of the Fountain Hills Dark Sky Association founded in 2017. “To preserve dark skies, we had to work with the entire town to update the local lighting code and convince residents to follow responsible outdoor lighting practices.”
Derksen and her team first tackled light pollution in the town center which has a faux fountain in the middle of a lake. “The iconic centerpiece, from which Fountain Hills got its name, had the wrong types of lighting fixtures, which created a lot of glare,” adds Derksen. They then replaced several other municipal lighting fixtures with dark-sky-friendly LEDs.
The results were awe-inspiring. After a long time, residents could see the Milky Way with crystal clear clarity. Star-gazing activities made a strong comeback across the town. But keeping light pollution low requires constant work.
Derksen and other residents regularly measure artificial light levels in
Fountain Hills. Currently, the only major source of light pollution is from extremely bright, illuminated signs which local businesses had installed in different parts of the town. While Derksen says it is an uphill battle to educate local businesses about light pollution, Fountain Hills residents are determined to protect their dark skies.
“When a river gets polluted, it can take several years before clean-up efforts see any tangible results,” says Derksen. “But the effects are immediate when you work toward reducing light pollution. All it requires is flipping a switch.”
Avalanche rescue dogs train to find and dig out people buried in snow slides
By the time he is three, Lume, like Huckleberry, will be a fully trained avy pup and will join seven other avy dogs on Breckenridge ski patrol team. Some of the team members, both human and canine, are also certified to work with Colorado Rapid Avalanche Deployment, a coordinated response team that works with the Summit County Sheriff’s office for avalanche emergencies outside of the ski slopes’ boundaries.
There have been 19 avalanche deaths in the U.S. this season, according to avalanche.org, which tracks slides; eight in Colorado. During the entirety of last season there were 17. Avalanche season runs from November through June, but avalanches can occur year-round.
High tech and high stakes
Complementing avy dogs’ ability to smell people buried in a slide, avalanche detection, rescue and recovery is becoming increasingly high tech. There are transceivers, signal locators, ground scanners and drones, which are considered “games changers” by many in avalanche rescue and recovery
For a person buried in an avalanche, the chance of survival plummets after 20 minutes, so every moment counts.
A drone can provide thermal imaging of objects caught in a slide; what looks like a rock from far away might be a human with a heat signature. Transceivers, also known as beacons, send a signal from an avalanche victim to a companion. Signal locators, like RECCO reflectors which are often sewn directly into gear, can echo back a radar signal sent by a detector; most ski resorts have RECCO detector units.
Research suggests that Ground Penetrating Radar (GPR), an electromagnetic tool used by geophysicists to pull images from inside the ground, could be used to locate an avalanche victim. A new study from the Department of Energy’s Sandia National Laboratories suggests that a computer program developed to pinpoint the source of a chemical or biological terrorist attack could also be used to find someone submerged in an avalanche. The search algorithm allows for small robots (described as cockroach-sized) to “swarm” a search area. Researchers say that this distributed optimization algorithm can help find avalanche victims four times faster than current search mechanisms. For a person buried in an avalanche, the chance of survival plummets after 20 minutes, so every moment counts.
An avy dog in training is picking up scent
Sarah McLear
While rescue gear has been evolving, predicting when a slab will fall remains an emerging science — kind of where weather forecasting science was in the 1980s. Avalanche forecasting still relies on documenting avalanches by going out and looking,” says Ethan Greene, director of the Colorado Avalanche Information Center (CAIC). “So if there's a big snowstorm, and as you might remember, most avalanches happened during snowstorms, we could have 10,000 avalanches that release and we document 50,” says Greene. “Avalanche forecasting is essentially pattern recognition,” he adds--and understanding the layering structure of snow.
However, determining where the hazards lie can be tricky. While a dense layer of snow over a softer, weaker layer may be a recipe for an avalanche, there’s so much variability in snowpack that no one formula can predict the trigger. Further, observing and measuring snow at a single point may not be representative of all nearby slopes. Finally, there’s not enough historical data to help avalanche scientists create better prediction models.
That, however, may be changing.
Last year, an international group of researchers created computer simulations of snow cover using 16 years of meteorological data to forecast avalanche hazards, publishing their research in Cold Regions Science and Technology. They believe their models, which categorize different kinds of avalanches, can support forecasting and determine whether the avalanche is natural (caused by temperature changes, wind, additional snowfall) or artificial (triggered by a human or animal).
With smell receptors ranging from 800 million for an average dog, to 4 billion for scent hounds, canines remain key to finding people caught in slides.
With data from two sites in British Columbia and one in Switzerland, researchers built computer simulations of five different avalanche types. “In terms of real time avalanche forecasting, this has potential to fill in a lot of data gaps, where we don't have field observations of what the snow looks like,” says Simon Horton, a postdoctoral fellow with the Simon Fraser University Centre for Natural Hazards Research and a forecaster with Avalanche Canada, who participated in the study. While complex models that simulate snowpack layers have been around for a few decades, they weren’t easy to apply until recently. “It's been difficult to find out how to apply that to actual decision-making and improving safety,” says Horton. If you can derive avalanche problem types from simulated snowpack properties, he says, you’ll learn “a lot about how you want to manage that risk.”
The five categories include “new snow,” which is unstable and slides down the slope, “wet snow,” when rain or heat makes it liquidly, as well as “wind-drifted snow,” “persistent weak layers” and “old snow.” “That's when there's some type of deeply buried weak layer in the snow that releases without any real change in the weather,” Horton explains. “These ones tend to cause the most accidents.” One step by a person on that structurally weak layer of snow will cause a slide. Horton is hopeful that computer simulations of avalanche types can be used by scientists in different snow climates to help predict hazard levels.
Greene is doubtful. “If you have six slopes that are lined up next to each other, and you're going to try to predict which one avalanches and the exact dimensions and what time, that's going to be really hard to do. And I think it's going to be a long time before we're able to do that,” says Greene.
What both researchers do agree on, though, is that what avalanche prediction really needs is better imagery through satellite detection. “Just being able to count the number of avalanches that are out there will have a huge impact on what we do,” Greene says. “[Satellites] will change what we do, dramatically.” In a 2022 paper, scientists at the University of Aberdeen in England used satellites to study two deadly Himalayan avalanches. The imaging helped them determine that sediment from a 2016 ice avalanche plus subsequent snow avalanches contributed to the 2021 avalanche that caused a flash flood, killing over 200 people. The researchers say that understanding the avalanches characteristics through satellite imagery can inform them how one such event increases the magnitude of another in the same area.
Avy dogs trainers hide in dug-out holes in the snow, teaching the dogs to find buried victims
Sarah McLear
Lifesaving combo: human tech and Mother Nature’s gear
Even as avalanche forecasting evolves, dogs with their built-in rescue mechanisms will remain invaluable. With smell receptors ranging from 800 million for an average dog, to 4 billion for scent hounds, canines remain key to finding people caught in slides. (Humans in comparison, have a meager 12 million.) A new study published in the Journal of Neuroscience revealed that in dogs smell and vision are connected in the brain, which has not been found in other animals. “They can detect the smell of their owner's fingerprints on a glass slide six weeks after they touched it,” says Nicholas Dodman, professor emeritus at Cummings School of Veterinary Medicine at Tufts University. “And they can track from a boat where a box filled with meat was buried in the water, 100 feet below,” says Dodman, who is also co-founder and president of the Center for Canine Behavior Studies.
Another recent study from Queens College in Belfast, United Kingdom, further confirms that dogs can smell when humans are stressed. They can also detect the smell of a person’s breath and the smell of the skin cells of a deceased person.
The emerging avalanche-predicting human-made tech and the incredible nature-made tech of dogs’ olfactory talents is the lifesaving “equipment” that Leffler believes in. Even when human-made technology develops further, it will be most efficient when used together with the millions of dogs’ smell receptors, Leffler believes. “It is a combination of technology and the avalanche dog that will always be effective in finding an avalanche victim.”
