Where has the night sky gone? Where is that thing called the Milky Way?
It is estimated that today over 80% of the world’s population live in “skyglow” (diffuse, scattered skylight attributed to scattered light from ground sources.) That means that four out of five people in the world do not or cannot see the night sky in its full, natural, startling, brilliance. Furthermore, in some parts of the world this percentage is significantly greater. In the US and Europe, the figure is 99%.
That Milky Way mentioned earlier. It is hidden to more than 2/3 of the world’s population.1
Losing this experience and being unable to see the stars has enormous consequences for us (humans) as well as for the non-human species that share this planet with us.
For well over 99% of our time on Earth as Homo sapiens we lived without light pollution. Our bodies, behaviours, psyches, and emotional states adapted to the circadian rhythm of life. Essentially, that rhythm is: day is light, night is dark.
However, over the past 100 years or so we have seriously disrupted that circadian rhythm. This has impacted our health and wellbeing.
Melatonin is necessary for our health. Melatonin is produced in our bodies in response to the circadian rhythm of life and helps to regulate and maintain our immune system.
When the circadian rhythm is disrupted, so too is our supply of melatonin.
[Could there be a correlation between the rise of diseases that our immune system would normally deal with and the disruption of our circadian rhythms? I am not in a position to be able to answer that, but the question is certainly worth asking.]
Not only is night light pollution disruptive of our health and harmful to wildlife, but it is also an enormous contributor to the world’s increasing electricity consumption. Visual Capitalist (whose aim is to help cut through the clutter of data in the world) claims that lighting makes up 19% of the world’s total electricity consumption.2 Presumably, night lighting is a significant proportion of that 19%.
Why? Why do we light up our cities at night? Why do we think that lights at night are a good thing?
Many will claim that night lights reduce crime and make us safer.
Yet there is little, if any, evidence to support this. Indeed, some research suggests entirely the opposite.
Research in England and Wales concluded that there was, “little evidence of harmful effects of switch off, part-night lighting, dimming, or changes to white light/LEDs on road collisions or crime in England and Wales.”3
Indeed, research in Chicago found a 21% increase in offending following the installation of lighting in Chicago’s streets and alleys.4 This staggering figure seems counter-intuitive, until it is pointed out that lights at night (when there are fewer people around) make victims and property easier to see!!
The increasing light pollution of our world is not good news for those of us who wish to be startled by starlight.
Our sense of place in the world, our identity of belonging to the Earth, is promoted and stimulated by our wonder, our awe, and our ability to be startled by nature.
When we lose that ability to be startled by one half of our ecosphere (the night sky) then we lose our sense of wonder. We lose who we are as humans.
Let’s turn off the lights and learn to be star-tled again.
1. Fabio Falchi et al. The New World Atlas of Artificial Night Sky Brightness, Science Advances, 10 June 2016, Vol 2 Issue 6.
2. https://www.visualcapitalist.com/anatomy-smart-city/ Accessed 12-12-22
3. Rebecca Steinbach et al., The effect of reduced street lighting on road casualties and crime in England and Wales: controlled interrupted time series analysis, Journal of Epidemiol Community Health, 2015;69:1118–1124. doi:10.1136/jech-2015-206012
4. Erica Morrow & Shawn Hutton, The Chicago Alley Lighting Project: Final Evaluation Report, Illinois Criminal Justice Information Authority, April 2000.