Too much of a 'good' thing
On darkness, daylight and reducing our use of artificial light
At some point in the early hours of this morning (22 December 2023), while most of us slept - at 3.27am GMT to be precise - the winter solstice occurred. After months of the days gradually getting shorter, each day will now have slightly more daylight than the last, until the summer solstice when the whole cycle begins again.
I find the reduced hours of daylight hard, and I am always glad when we reach this point of the year and the days start to lengthen again. I know the coldest months are still to come but I love those crisp, bright winter days when the sun can transform even the dullest patch of frosty grass into a thing of sparkling beauty. Frosty conditions can be beautiful at night-time too especially when moonlit. We haven’t had much weather like that in London so far this year and the lack of sunshine has made some days recently feel very short indeed. The last couple of times I’ve been out volunteering, the light has already been fading by 3pm. And there have been many days when the sky has been so dull and overcast it’s felt as though it has never truly got light outside.
Humans have been seeking ways to brighten the darkness for thousands of years. For most of that time they were dependent on whatever natural materials were to hand, and the solutions they came up with such as rushlights made from reeds dipped in animal fat often produced more smoke and smell than light. When providing any form of artificial light was either time-consuming or expensive, all but the very wealthiest had to use it sparingly. The invention of gas-powered lighting and then electricity changed that.
Having light available at the flick of a switch extended the hours of work, gave us more leisure opportunities and made the streets feel safer and more welcoming to those afraid of the dark. In the centuries since we’ve taken full advantage of the many benefits of artificial light, and as we have produced ever increasing amounts of it, what started as a good thing is now creating more and more light pollution in the world around us. Brightly lit windows in offices, shops and homes, streetlights, car headlights, stadium floodlights, security lights, advertising hoardings and more - there is artificial light everywhere in the modern world. And, of course, at this time of year, there are lots of extra decorative lights too.
As with so much of our behaviour, we’ve given too little thought to the impacts that our efforts to banish darkness are having on wildlife. While humans are diurnal, and most active during the day, many insects and around 70 per cent of mammals are nocturnal. We are robbing these creatures of the night-time they need for feeding and mating. Light-avoiding species such as bats are now less easily able to use darkness to hunt at times when they are not at risk of being caught by birds of prey. Millions of migrating birds die each year as a result of becoming disorientated by artificial light and colliding with buildings. Moths are unable to reproduce successfully, plant pollination is suffering and street lights are causing trees to shed their leaves later.
Artificial light isn’t necessarily a benefit for the species that rely on daylight either. If they become more active at night, they will be competing with nocturnal species for food and will miss out on the rest and sleep they need. This is something which affects the minds and bodies of humans too. Disruption to our circadian rhythms (our natural sleep-wake cycles) has been identified as being bad for our health, contributing to a range of conditions including diabetes and depression.
While artificial light may have increased what we can see close to, it has cut off our long-distance views, and reduced our sense of connection to the wider universe. Less than a tenth of the population of the UK can now see the Milky Way from where they live. In London, there are no truly dark skies and ‘skyglow’ almost completely obscures any view of the stars.
All this lighting makes a significant contribution to carbon emissions too. The introduction of more energy efficient LED light bulbs has had little impact on this as it has simply resulted in more lighting being installed.
It’s not all doom and gloom though. Unlike many of the other impacts of modern life, it is as easy to reduce light pollution as it is to cause it. We can turn off unnecessary and excessive lighting and design the lighting we do need more carefully. I certainly don’t want to suggest we get rid of all our Christmas lights – in a heavily illuminated city like London, most smaller displays are unlikely to make too much difference - but I don’t think anyone needs lights that are designed to be visible miles away like the ones the Shard has installed this year and I like this suggestion of having a big switch OFF, before the annual Christmas lights switch-on.
Most positively, there are quick and inexpensive actions we can all take as individuals - ensuring lit windows are covered by blinds or curtains at night or using warm-colour temperature bulbs and motion sensors for outdoor lighting and avoiding lighting up trees that could be feeding sites for nocturnal wildlife. We can satisfy our desire for light without destroying the darkness other species need and these small and simple measures could make a huge difference to the wildlife that relies on our gardens.
To finish…
…a few things I’d like to share:
Dark Sky London: This community group aims to ‘rewild the night in London’. Their website includes lots of useful information and resources including details for places to go stargazing in and around London and a list of books and articles with more information about light pollution and the night sky.
An ethereal gravity: In this edition of her Witness Marks newsletter, Melissa Harrison describes her experiences of being out alone, after dark, night-walking, in a rural area with no street lights, something I’m determined to become more confident about doing. As she puts it: To only ever walk in daylight…is to limit what you can know about a place, to circumscribe your relationship with it…
The Lost Rainforests of Britain by Guy Shrubsole: This is a well-researched, and very inspiring, assessment of the opportunities for restoring the temperate rainforest which once covered much of the Western side of Britain. Shrubsole describes in vivid detail the vast array of species these places contain, species such as mosses and lichen, many of which are slow-growing and highly sensitive but which, like the fungi I talked about last time, we have a tendency to overlook. I’ve been to some of the places described and thought they were amazing but it is only after reading this book that I can truly appreciate what rare and special habitats they are, and the benefits they deliver for both climate and nature.
Nice one. It is a good, interesting read.
I was just working on a light pollution piece myself! Lovely article, thanks for writing it.