THE 18th century French philosopher Jean-Jacques Rousseau did not believe that God approved of street lighting. He thought that humans risked losing their souls in an overly artificial world! That was in the days of gas street lamps.
The first incandescent electric light bulb was commercially produced in 1881 by the English inventor Joseph Swan and the first city in the world to use such as street lighting was Newcastle, in the UK, in that very year.
How many times have we heard ourselves saying to family members, “Turn off the light”? For five years in my life, my family and I lived in the seaside resort of Blackpool in North West England where ‘The Illuminations’ are a prominent feature of Lancashire life. These decorative lights will again be switched on from Sept 1 to the very end of December this year as an extension of the summer season, gaining extra trade for hoteliers.
We used to take our two very young daughters for a saunter on a Saturday evening along 5km of Blackpool’s 10km promenade to see ‘The Lights’. We never questioned the cost of this lighting in our annual council rate bills and just marvelled at the one million light bulb displays. How the world has changed in 50 years.
Yesterday, we celebrated ‘Earth Hour’, when we were encouraged by the World Wildlife Fund to extinguish our lights for one hour between 8.30pm and 9.30pm as a symbol of commitment to our planet Earth. This event was first started in Sydney, Australia, 16 years ago and today, globally, nearly every country celebrates this hour without artificial light.
It has been estimated that 83 per cent of our world’s population live under light polluted skies and that nearly a quarter of the world’s land area is affected by ‘sky glow’ — a dome-like shield of light pollution over urban areas. Worldwide, light pollution has increased by over 50 per cent this century.
Light pollution is caused by artificial lighting competing with moonlight and star lights in dark conditions. It is a side effect of civilisation and includes the exterior and interior lights of buildings, advertising beacons, car parks, offices, factories, sports venues, and road lights. How many of us are very annoyed at night, that without blackout curtains, we have street lights glaring through our bedroom windows?
From the night time garden of my home, deep in the countryside in South West England, I can marvel at the heavens above, observing the Milky Way and other planets together with the overhead passing of the International Space Station on its orbit around our plant. It is estimated that 33 per cent of the world’s population can no longer see the Milky Way with 80 per cent of North Americans and 60 per cent of Europeans deprived of this night-time spectacle.
The most light polluted country in the world is Singapore, while Hong Kong was declared the most light polluted city in Asia. Maybe this is for security and as assistance to traffic flow in densely populated cities. Critics of the ‘Earth Hour’ concept argue that a worldwide switch off of lights for one hour only reduces the world’s total consumption of electricity by 5 per cent on that day.
In reality that seemingly small amount does have an impact when viewed against the damage to the atmosphere caused by thermal powered electricity generating stations.
The night time sky glow of urban areas can be seen in the skies of rural environments. I can even see the glow of the nearest small town (population: 14,000) to me, 10km from my home in Somerset, UK. John E Bortle, an amateur American astronomer, in 2001 produced a graduated scale of the severity of light pollution, numbering 1 to 9, thereby helping us to judge the darkness of the sky.
Class 1 shows excellent darkness whereas Class 9 shows very bright illumination associated with inner-city skies. He maintained that, in the 1970s, he only needed to travel for an hour from a major population centre to find truly dark skies. In 2001, he needed to travel 200 miles for the same effect. This is an interesting piece of research which can be applied anywhere in the world.
Ecological impacts of light pollution
The presence of night light does disturb ecosystems. Some spider species avoid well lit areas whilst other species are enhanced in their night time activities in building webs beneath street lights. Inevitably these lights attract most flies. Human sleep patterns may be disrupted by the glare of street lights leading to sleep disorders, depression, and stress.
Moths also experience death through starvation from the lack of night flowering plants in well-lit environments which they help to pollinate or through the jaws of bats. In darkness, moths have evolved acute hearing thereby picking up the high frequency sounds made by bats. As soon as the environment is lit up, the moths become totally deaf to bat sounds and movements and become easier prey. Congregating under street lights, moths become gobbled up by bats. Male glow worms mistake city lights for a host of lit-up females and thus never find a mate.
Light pollution around city lakes prevents some species of zooplankton, which feed on algae, from developing and thus lead to algal blooms, which destroy the plant life of lakes besides causing a deterioration in water quality affecting humans and fish.
High rise buildings, illuminated at night, can cause the disorientation of migrating birds and their survival rates. Night time bird migration is more frequent than one imagines, for the birds not only conserve water in cooler flight conditions but city lights outshine the stars which the birds naturally use for navigation. Fatalities have also been observed in bird collisions with buildings.
Turtle hatchlings on beaches near well illuminated tourist resorts are attracted to the lights of seaside eateries, mistaking them for the moonlit distant horizon of the sea. Rather than moving seawards they crawl landwards and become victims to dehydration, exhaustion, cats, and night time vehicular traffic.
During the height of the Covid-19 pandemic, there was a respite for nature as fewer people were seen in our inner city areas of tourism, restaurants, night clubs, and drinking spots. Such facilities were closed down and the need for street lighting and illuminated advertising signs was less. Road traffic was drastically reduced as more people worked from home. The ‘shutdown’ had a massive effect upon night time light pollution and this was well illustrated in Nasa space shots.
Today, Britain has faced yet a further reduction in night glow as electricity consumption prices have suddenly doubled in the last six months and people have switched off their lights earlier and high-rise office blocks are no longer flooded with night lighting.
Electricity companies have offered rebates in their charges for people with smart meters, who do not use electricity for cooking purposes from 5pm to 6pm each day when there is normally peak time electricity usage.
There, ‘Earth Hour’ has taken on a new meaning and long may it continue. We all have a greater duty than ever before to ‘Switch off the light’!