59. The Challenge of Light Pollution

Our abuse of the natural world is causing problems which grow more terrifying with every passing day.  

Understandably, climate change and the physical destruction of entire ecosystems attract the most attention. 

But we face another environmental threat - one which is insidious and fast-growing, yet still widely ignored. 

Light pollution.

The world we inhabit was, until modern times, governed by strict astronomical laws. Day followed night, and the night was always dark - except when the moon was full. This celestial regime shaped the behaviour and biological rhythms of (almost) every living thing on the planet. 

The coming of electric light changed everything - and continues to do so. In many places true darkness now never comes. And while we may welcome that change because some of our deepest fears are associated with darkness, all that new light is causing immense damage. 

There is overwhelming evidence of the destructive effects of artificial light on the animals (and plants) with which we share the planet. 

To give just a few examples, it is likely that billions - yes, billions - of migratory birds die when they are drawn to brightly lit buildings. And even that number is dwarfed by the number of insects that suffer a similar fate. Then there are the countless, doomed turtle hatchlings that are lured away from the sea by artificial light.  

Light pollution is a major but little-noticed factor in the massive problem of biodiversity loss. 

Moreover it is increasingly clear that by banishing darkness we are also damaging our own health and well-being.

Exposure to artificial light at night is associated with a host of physical and mental disorders including diabetes, depression and even some forms of cancer.

And we are suffering other, less tangible but important injuries.

The darkness that once permitted everyone on the planet to see thousands of stars, as well as the glowing ribbon of the Milky Way - our home galaxy - has been obscured by the halo of artificial light that surrounds every town and city. The arrival of the LED has only made matters worse.

Most people living today will never see the night sky in all its glory. 

The facts are not in dispute.  In some countries (France, for example) governments are already taking practical steps to address the problems of light pollution. In the US there are many cities that have taken steps to reduce the glare of outdoor lighting.

But the British government rejected an amendment to the recent Environment Act that would have added the reduction of light pollution as a target. 

Low public awareness is a major obstacle, coupled with the common assumption that more light must be better, and a widely held (but questionable) belief that it always improves our security.  

Few people realise that the worst effects of light pollution can be reduced or eliminated by taking a few simple, inexpensive steps - such as installing lights with warmer colours, shielding them so that they don’t not spill upwards into the sky, and using motion sensors so that they only come on when needed. 

The best solution of all - just turning unnecessary lights off - has the great additional benefit of saving both energy and money.  

Often it is enough to draw someone’s attention to the problems. I recently persuaded the British Army to remove some outrageously bright lights from a military base in the middle of Chichester Harbour (a nature reserve on the South Coast of England) simply by having a conversation with the senior officer in charge. 

In the UK, the Council for the Protection of Rural England’s (CPRE) annual ‘star count’ has helped people become more aware of the problem of ‘skyglow’ - and it’s good news that several Dark Sky Parks have been designated in the UK.  

But while some UK charities take an interest in light pollution, none treats it as a priority. Because all their efforts are small and fragmented, progress in tackling the problem has been painfully slow.

 Much more needs to be done. 

 So here are a few ideas: 

Why don’t British environmental charities devise and adopt a code of conduct in relation to light pollution? 

Why don’t those same charities ask all their grant recipients to follow a similar code of conduct? Perhaps they could offer extra funding for this purpose. 

A good way of raising public awareness in the UK would be to establish an annual prize in recognition of outstanding achievements in tacking light pollution. Who would like to take this on? 

Above all, policy change is needed. Will one of our leading environmental charities launch a campaign to get the government to regulate light pollution? 

Yes, it’s a big challenge, but it’s also an urgent one.  

51. The night sky and the problem of light pollution

I spent the month of July sailing from Southern Greece to Northern Spain - a 2000 nautical mile voyage in a 14-meter yacht.

It was the first time I’d been out of sight of land since the start of the COVID pandemic.

As we headed across the Ionian Sea to Siracusa, I saw a red sun disappear beneath the horizon with the briefest wink of green light. The so-called ‘green flash’ - so rarely seen that some doubt its reality!

On watch that night I was treated to the sublime spectacle of a truly dark night sky, unpolluted by artificial light - stretching from horizon to horizon.

The arch of the Milky Way glowed above us and the occasional meteor briefly slid across the sky. Jupiter and Saturn rose slowly in the east, Antares glowed low in the south, Arcturus descended towards the western horizon, and Cassiopeia looked down on us from her throne in the northern sky.

A mysterious rain fell from that cloudless sky - a rain of wonder and peace - and I felt a strange, spine-tingling joy.

Among all the many precious things threatened by our reckless and greedy commitment to what economists and politicians call ‘growth’, is the darkess of the night.

Most of us now live in towns and cities where artifical light veils all but the brightest stars. And the plague is spreading ever wider. The night we see is quite different from that with which all our ancestors were familiar. Different, and profoundly impoverished.

Yet unlike many of the environmental problems we face, light pollution is relatively easy to fix.

It’s not difficult to turn off the many lights that serve no useful purpose, and it’s easy to shield those that we really need so that their light isn’t wastefully poured into the sky.

Light pollution is a serious threat to the welfare of many of the creatures with which we share the planet - from migratory birds and insects, to amphibians, crustaceans, reptiles and even plants. And there’s a strong body of evidence that it’s bad for our health too.

Of course reducing light pollution would also save a great deal of money as well as reducing energy consumption and CO2 emissions.

The UK Parliament is currently considering a new Environment Bill which contains a number of key targets. Bafflingly, however, reducing light pollution is not yet among them.

The UK charity Buglife has been working hard, in collaboration with others, to change that, but they need all the help they can get.

If, like me, you want to see light pollution reduced, why not lend Buglife your support? You can do so by joining as a member or by writing to your MP (if you live in the UK) to support their proposed amendment to the Envirnoment Bill.

You might also be interested in supporting the impressive work of the excellent US-based International Dark Sky Association.

50. A bit of a catch-up...magnetoreception in birds, place cells in bats and misguided beetles.

Off the coast of Portugal a week or two ago…

I’ve been away for a while, on the high seas, doing some real navigation in the Mediterranean and Atlantic - and tasting a bit of freedom after all those months of lock-down. Good to see some wildlife too: lots of Cory’s shearwaters, dolphins, green turtles (a few), a humpback whale breaching, swordfish leaping…even an errant hoopoe heading south towards the distant shore of Africa. I hope it made it!

Now I’m home again, I’ve been catching up on the latest research. Here are a few highlights that caught my eye.

First, there was this paper about magnetoreception from Jingjing Xu et al. This strengthens the case for cryptochrome molecules in the retina of night migratory birds being the basis of their magnetic compass sense. This theory - which I also discuss in Supernavigators/Incredible Journeys - is the subject of enormous research interest at present. Eric Warrant has provided a really good commentary that explores the significance of this piece of research. As he explains, Xu et al. have made a major advance by showing that ‘the version of CRY4… in the migratory European robin has a crucial property needed to sense Earth’s magnetic field: the ability to form radical pairs that have high magnetic sensitivity’. Moreover, they have demonstrated that CRY4 is more sensitive in the robin than it is in other, non-migratory birds.

Then there was this fascinating article by Eliav et al. about how bats navigate. Up until now, most of what we know about how the brains of mammals support their ability to navigate has come from laboratory-based studies of rats and mice (and humans). Nachum Ulanovsky and his colleagues in Tel Aviv have however developed wireless techniques for recording the activity of single cells in the brains of bats on the wing! This latest paper shows that single place cells (which ‘represent’ the positiion of an animal in space) in bats flying through a long tunnel can operate on a range of scales - from about 1m to 30m. This multiscale coding provides a really efficient way of representing large environments of the kind that bats inhabit. It will be very interesting to see what emerges when this kind of research is extended to other animals that navigate over long distances - like birds.

Finally I want to mention a piece of research that touches on something that really bothers me: the scourge of light pollution. In this paper, James Foster et al. have shown how light pollution can seriously interfere with the navigation of nocturnal dung beetles - which rely on polarised moonlight and the orientation of the Milky Way to maintain a straight course as they roll their balls of dung. They found that ‘that light pollution…induces dramatic changes in dung beetle orientation behavior, forcing them to rely on bright earthbound beacons in place of their celestial compass’. The beetles are attracted toward artificial lights, and this results in more competition between individuals and reduced dispersal efficiency. As the authors rightly observe, ‘for the many other species of insect, bird, and mammal that rely on the night sky for orientation and migration,
these effects could dramatically hinder their vital night-time journeys’.

This important article by Van Doren et al. also relates to light pollution. Based on historical records at a site in Chicago, it suggests that bird deaths caused by collisions with lighted buildings could be substantially cut by reducing lighting to more sensible levels.

Here also is a link to good BBC article about the problem of light pollution.

That’s all for now.