Light pollution is a serious issue. Many studies from the most eminent institutes have been conducted discussing how artificial light has an affect on health and the quality of life for wildlife, ecosystems and humankind. These studies can be researched quite readily so I advise, if you care, to look around the internet to seek out the truth. One of the widely known harmful complications that arise from unnatural airglow (see the links below for more detail of this in magnitudes for natural and artifical) is the effect it has on the aspect of clear skies. Astronomers have to battle to view through the reflective atmosphere in order to make out stars near the majority of areas where humans live. That is why the best telescopes are on mountains or isolated deserts far from artificial light sources.
This pollution is getting worse in the developed world. If we go back to 1994 during a black out in Los Angeles. Police started to receive calls from members of the public who were seeing a strange object in the sky. That object was the Milky Way. Back to the present day and with the increased light sources, a paper from the Light Pollution Science and Technology Institute in Italy states from 2020 60% of the population in Europe can’t see the Milky Way. In America that is 78% and these figures are increasing rapidly.
There is a more concerning effect that comes from unwanted light. As with air pollution, light is causing health issues and these too are increasing year on year. If there is too much of the wrong kind of light then the circadian system starts to become confused. This is the human biological functions controlled by the inner clock. The eyes have a third photoreceptor that was discovered in the 90’s. It is mainly responsible for the input of light for the circadian system being particularly sensitive to light on the blue end of the spectrum. This is important to make sure the body stays in check and alert to those shifts in the days natural light. Mess with the clock and mental health starts to suffer.
So our inner clock gets mixed up, what has the latest science research brought to the table. The American Medical Association, in an early 2016 report, found definite links with depression, insomnia, dementia, diabetes, heart disease and cancer. If that seems far fetched then let’s look at reports from Nasa and Stanford University. This involved 15 thousand participants who were studied for the amount and quality of sleep. It was a full study using GPS from their homes and used satellites viewing light levels at night. The result showed those with greater light levels at night had delayed bedtime and wake up time ensuring increased daytime sleepiness. importantly this same inner clock is in all living organisms. Wildlife and plants have different versions of the circadian system.
A 22 year study of 100 thousand nurses published their findings in 2017. It was found that those that lived in areas with more outside light interference were at greater risk to develop breast cancer. This is even after accounting for individual and area risk. It has to be stressed that the study had confidence in 5% at a 95% confidence level. Not a huge increase but enough to be sure the light risk should be reduced.
The science is well proven that hormone levels have a link to cancer risk. The connection to the blue part of the spectrum causing imbalance comes from that internal clock of the circadian system. Scientists believe that this alters the hormone levels. Two other studies seem to support the research. In Israel from 2008 with artificial light connected to breast cancer and a 2019 study from Spain. This was over 5 years and with several thousand people involved. Those exposed to light pollution from the blue part of the spectrum had 47% developing breast cancer and 100% with prostate cancer. Note that the percentages are those that researchers were confindent the light was the instigating factor.
Wildlife are in the innocent party yet again to human behaviour. Light pollution has been proven to be responsible for killing 5 to 50 million birds every year in North American alone. The United States Fish and Wildlife Service states that the glow from cities confuses the birds into thinking the sunrise is near. They become chronically exhausted due to lack of sleep and fall victim to predators and illness. I could go on with the ways in which wildlife is affected around the world but the article will become a novel. If you decide to research then start with the links below. I will give common sense tips to help save lives by reducing outside light at night. If you are reading this and chose to ignore it then it is your choice, just as it is the decision for those to still drive combustion engines with exhausts near a child height. They will do it no matter what research shows. Like smokers with packets of cigarettes display graphic depictions of illness still smoking. Some are just lost causes and my mantra is always that forward thinkers will change the pattern.
This is getting constantly worse as a 2017 paper researched from Europe and America shows. All areas with artificial light pollution increases 2.2% every year. This in areas with or without light at present.
So we can see the negative effects of this always on night light pollution. What should be done. Firstly the white light can be changed for light in the yellow spectrum. This is luminance that is conducive for better sleep patterns. Secondly the light must be directed downward which thankfully new LED lighting does achieve. Thirdly home or business lighting needs to be timed or on intermittently. Security lighting should always be only tripped when detecting movement. This has two advantages. It is more of a deterrent than always on and if it is white light will have a negated effect on both wildlife and humans. Fourthly check if the lighting is needed, if it is then reduce the brightness or the time it is on for. Where I live the street lighting is LED in the white spectrum and I have seen bats confused as well as birds calling way into the night. Thankfully the local council do have them on timers that turn off a number of them at 12 at night. A gradual step further would be to change to lights in that yellow spectrum. I have sent a letter to my member of Parliement with the evidence and I recommend you do the same.
Personally for home use I use a number of Lumie lights and even have one at work to keep me alert. I find the Lumie Halo particularly useful. It highly adjustable and counteracts the unnatural lighting both outside and in. I wake to a Lumie that gradually has sunrise. At night it emulates the yellow light of sunset, steadily fading like the setting sun. I recommend them to refresh where unnatural white light causes the issues described above. I just wish wildlife was protected from the human need to overpower nature. That protection is gaining more traction as the stilted generations move aside. This is definitely a discussion for another time.
Here are a few links to get started:
An interesting light pollution study at Science.org
A charity to make the countryside better Nightblight
An interactive map to find clearer skies Darksitefinder
The Natural History Museum with an article on Wildlife and Light Pollution that includes excellent tips