Light pollution: time to flick the switch
Many people don't recognise light pollution at night for what it is: pollution. Largely, we fail to see this harmful introduction into the environment because we have been conditioned to associate light with good and dark with bad. It's time to change that. In this episode, we explore the various implications of artificial light at night and speak to the activists trying to put a stop to it.
In this episode
00:42 - Excess light stunts astronomy and sea turtles
Excess light stunts astronomy and sea turtles
Imma Barrera & Xander Byrne, University of Cambridge & Thomas Reischig, Turtle Foundation
James Tytko spoke with Imma Barrera and Xander Byrne about the disruption of light pollution on the study of the stars, and also Thomas Reischig about the harm done from light at critical points in the lives of sea turtles...
James - The temperament of an Astrophotographer is one of patience…
Imma - ’I tried 3 nights in a row, I needed no clouds in the sky, low tides, no winds so that the water was calm enough for the reflection.’
James - Imma Barrera is describing the lengths she went to capture the stunning picture of the Milky Way she’s sent me. Shot in the Acadia National Park in Maine, it depicts our galaxy in magnificent detail, the stars mirrored in the tranquil water below. Imma travels the United States, taking pictures of the awe inspiring vastness and beauty of our universe.
Imma - ‘That’s what makes that picture unique - always the story behind that picture.’
James - Recently, though, her work, and that of all astrophotographers, has been made even more trying than it already was…
Imma - ‘Last time I was tracking in New Jersey I was mostly guessing where the North Star was.’
James - Fewer people than ever have the simple pleasure of staring up into the sky at night and witnessing the breathtaking beauty above. That’s because its mostly concealed by sky glow as it’s known, an effect of light pollution…
Imma - ‘I just started in 2015, it’s getting harder because of the intensity of the light pollution.
‘For instance, here in New Jersey, I can forget going in the summer, the same I can say for North Carolina; when the tourist season starts you can forget it.’
James - Imma’s pursuit is artistic, but sky glow is hampering other disciplines as well. To find out how light pollution is impacting the scientific study of the stars, I visited the University of Cambridge’s Institute of Astronomy to catch up with Xander Byrne…
Xander - So we're currently in the 16 inch telescope dome which we have here at the Institute of Astronomy. We mostly use it for outreach stuff, but yeah, we're in a big dome, which is why it's so echoey.
James - You mentioned that this telescope these days is mainly used for outreach purposes. I wonder if you could tell me why that is?
Xander - When the institute was being established, centuries ago, it was right out on the edge of Cambridge beyond the boundaries. And this is because there was a little bit of light pollution from the city, mostly like candle lit street lamps, for example. But as the city has expanded in that time, the institute is now within Cambridge proper and obviously there's a lot more in the way of street lighting and domestic lighting in the city. And so there's just too much pollution to do any kind of observational research from right here.
James - That's really interesting. So the institute was sort of strategically placed outside of the limits of where the light pollution would touch and research has had to stop going on here. So where is most astronomy based research done these days?
Xander - The biggest observatories that are in operation today are usually in very remote places, often where it's quite dry as well because humidity can also affect astronomical observations. So a very good place where a lot of observatories are is in the Atacama Desert in Chile. There's a lot of new ones being built there as well. The Vera C. Rubin Observatory in particular, which is coming online next year, hopefully. There are also other places on remote islands which are also quite good. So there are a couple in Hawaii, some in the Canary Islands as well. Coincidentally, also quite good places to go on holiday, but, I'm assured that that is just a coincidence.
James - I'm sure it is. You guys have got all sorts of cool kit to call upon when it comes to observing the sky. Is it really the case that the tools at your disposal are not able to overcome the light pollution problem?
Xander - To some extent, astronomy is always going in a direction of looking for fainter things because the brightest objects are sort of low hanging fruits and much easier to do science on. We kind of know what they're doing, so we are now really trying to probe the most distant, the faintest objects, and that's becoming a lot more difficult to do as a result of the light pollution.
James - And this is a problem that's only set to get worse, not just as countries industrialise further but the development into space and the satellites that orbit the earth.
Xander——因此可能面临相当大的问题observatories today is satellite tracks, which sometimes appear in astronomical images which are being taken, you have these bright streaks going all the way across. So for example, I mentioned the Vera C. Rubin Observatory: it's been estimated that they might have to throw away something like 40% of the images that they're going to be taking just because they're going to be contaminated with these satellite trails, which is pretty sad really. One argument that, unsurprisingly, Elon Musk has proposed is that we just put loads of telescopes into earth orbit and that would solve all the problems. But even the Hubble Space Telescope, which is obviously in orbit around the Earth, has sometimes seen trails of satellites orbiting at higher altitudes than it crosses its path. So even putting everything in space wouldn't necessarily solve all of our problems
James - And presumably makes it all a lot more expensive?
Xander - Yeah, by like a factor of 10 more expensive. So it's really not a solution
09:53 - Constant light causes harm to head and heart
Constant light causes harm to head and heart
Franceso Cappucio, University of Warwick
Chris interviewed the University of Warwick's Francesco Cappucio about the health impacts of light pollution...
Franco - Light is the most important environmental cue that we have for synchronising our circadian rhythm. So any change that happens in the light-dark cycles will cause changes in the way our biological clocks work, and therefore will affect our sleep patterns in terms of quantity and quality.
Chris - And what's the evidence that, if you have those sorts of disturbances, the health impacts are negative?
Franco - The epidemiology of sleep in large populations has clearly shown that disturbances in terms of quality and quantity, so deprivation and also the fragmentation, are associated with the short term effects that we may all know and recognise: reduced alertness, reduced performance, low mood. But, also, more worryingly, now we know there are long term effects, and the long term effects are quite serious. We go from an increased incidence of obesity, high blood pressure and diabetes, to a more significant increase in fatal and nonfatal heart attacks and strokes, not to mention in mental health, depression, anxiety. And there is some evidence now to link disruption of sleep to some forms of cancers like breast cancer and prostate cancer.
Chris - Can we causally link that? Do we know, for example, that light pollution is causing the dysregulation of our body clocks and that is causing these diseases?
弗朗哥-长期条件而言,他们can only be taken from experimental studies that have a shorter duration. But, if you manipulate, for instance, a sleep duration or you disrupt sleep in different ways, you can have reversible cardiometabolic and functional effects which, if sustained, would lead to serious conditions. We know that those effects are reversible when we change the disruption of sleep, so there is a very direct link between how much sleep is reduced in terms of quantity or is disrupted and the entity of the cardiometabolic, and also mental health issues that you find later on.
Chris - In these contexts, what do we actually call light pollution then? What do I need to be exposed to to cause these sorts of disruptions and therefore put myself at risk of the sorts of conditions that you've been outlining?
弗朗哥-光在调节系统性红斑狼疮的重要性ep is quite complex. We have some biological clocks in our brain, the kick, to give us a day, night cycle, but they're not exactly 24 hours. We have a system through our eyes that detects day and night in order to tell the body clock to resynchronise every day to the 24 hours which is our conventional day that we have created as human beings. Now, that light that eventually comes to the body will stop one hormone called melatonin, which we call the sleeping hormone. And when it gets darker, the eye transfers that message. So the melatonin goes up and we tend to fall asleep. And vice versa; when daylight starts in the morning, the melatonin shuts down. So these are mainly affected by what we call blue light. The blue light has the effect of day, has an intensity and spectrum very similar to the sun. Whereas a red light, which is of less energetic light with a longer wavelength, is more conducive to sleep or dozing off. So, in reality, we need to avoid, during the night any light which is bright (is blue, has high intensity and spectrum.) I'm afraid we have many lit environments at night which have very bright blue light, and that can obviously disrupt sleep in the people exposed to it on a regular basis.
Chris - So is one mitigation that we either dissuade people from exposing themselves to these blue lights - because television screens these days, laptop screens, mobile phones, screens, these things are on all the time and we're all deluged in this light. We're all disrupting our body clocks then. Is it just that we've got to turn those things off or are there other ways that we can mitigate this so that they don't impact on our sleep in the same way or to the same extent?
Franco - Well, that's very important. First of all, let me give you two or three numbers. In 2008, estimates were that 50% of the human population now lives in urban areas, and by 2050 it's estimated that more than 90% will be urbanised living in cities. Now, when we work out how much time we spend indoors in cities, at the moment it's nearly 80% and one third is spent in our bedroom. So when we get these numbers, we understand that the first thing is the indoor activity of light has to be regulated so that it is conducive to maintaining our day and night cycle. Otherwise, we'll always be awake. There are rules for individuals that they need to follow. And definitely not having a screen in the room is the first thing, particularly if it projects very blue high intensity light. But also we need to understand that most of the indoor activity happens in offices, in schools and, in particular, in hospitals. I have experience where being in a hospital at night is terrible because the lights are on all the time and patients can't sleep. Therefore, there is an issue between awareness and behavioural change. I would put sleep and light pollution and other problems within the domain of public health and policy where I think there needs to be more societal change. For instance, architects and planners at the moment might consider lights using the the visual performance type of problem. They don't consider what the non-visual effects are, which is exactly what we're talking about.
16:49 - Spread awareness to stop surplus light
Spread awareness to stop surplus light
Ruskin Hartley, DarkSky
What can we do about light pollution? Ruskin Hartley is the Executive Director of DarkSky International. Chris asked him what they're trying to achieve and what inspired him to take up this mantle…
Ruskin - I'd worked in conservation for the better part of 25 years, working on restoring ancient forests, trying to remove plastics from the ocean. I'll be honest, until five years ago, I hadn't really thought about light pollution as an issue, and as I came across it, I realised not only did it impact almost everything I cared about from a conservation perspective but, also, amongst issues I'd been tackling, it was one of the easiest to be solved.
Chris - You make it sound like there is a solution just waiting to be voiced then. So how do we tackle it?
Ruskin - Our organisation, Dark-Sky International, believes that the solution to light pollution actually comes from better quality lighting. This is not about turning off all the lights and plunging us into medieval darkness as some people like to say, but it is thinking about natural darkness as a precious resource. Light is something to be used sparingly and thoughtfully to meet our needs whilst mitigating the impact on wildlife, human health, climate, energy change, you name it. All those things that people care about.
Chris - I think also it's sort of ingrained into us, isn't it? That light equals good, dark equals bad, light combats crime, dark begets crime. And so it's a self-fulfilling prophecy, we put new houses up, we build new developments and new facilities, and they all come with a host of lights.
Ruskin - Yeah, many of the world's religions, the great books go back to that dichotomy of light and dark, right? So yes, it is there. Now, the reality is, until a little over a hundred years ago, and I think Newcastle was one of the first cities in the world to be lit with public streetlights, outside the world at night essentially was dark. And people were used to stepping outside at night and seeing the stars overhead unless it was cloudy. In fact, all of us were, in a sense, astronomers. We marked out the passage of time through the passage of the stars, and we have essentially lost that connection both to the natural world and to the stars overhead. And I think that has been a great loss, an immeasurable loss, to society. Now, today, 83% of people around the world live under light polluted skies. 99% in Europe and North America have lost that connection to the night sky because they live under light polluted skies.
Chris - Are you getting traction when you put your arguments to people who are policy makers, decision makers, are they receptive or do people say, look, this is a first world problem. We are grateful we've got some lighting.
Ruskin - I think it depends. It is always hard to answer those broad brush questions. We can answer it with specifics. There are certainly many communities, both large and small, who are starting to understand that light pollution is a real issue and better quality light can help deal with some of the other concerns of their community. Tucson, Arizona, where we are based, they are very protective of their dark skies because of the impact that has on the surrounding astronomy community. So when they upgraded their streetlights a number of years ago, they established from the very start that they wanted to both save energy by transitioning to more efficient LED based street lights but, at the same time, they wanted to make sure they mitigated and reduced light pollution. And by establishing those twin goals, they're able to save, I think it was 2 million US dollars per year in energy costs. And they also reduced light pollution as measured by the astronomers by 8%.
Chris - You mentioned LED lighting. While this is a game changer in efficiency terms because it's so much more efficient, you are wasting so much less electricity and turning more electricity into useful light rather than invisible heat, that people calculated that in fact they could have more lighting for less electricity spend because of LEDs and so, in fact, they increased and intensified the lighting. So it can be a double-edged sword.
Ruskin - That is absolutely right. Unfortunately, what has materialised is a great increase in light pollution as a result both by putting out more light and also changing the quality of the light that's put out there. We have essentially transitioned to a world where we're spewing far more short wavelength blue rich light at night into the environment than has ever been seen before. Essentially, every white LED streetlight out there is really a blue LED based street light with some clever chemistry so that we perceive them as white, but those blue rich emissions that are there are driving sky glow and are much more impactful on biology and so fundamentally changing the ecology of the night.
Chris - It sounds a bit from what you're saying, like the pill is a bit worse than the ill then with this, unless we're very careful?
Ruskin - Well, I think the trick is to be careful and I don't think the pill is worse than the ill. I think it's how much and how you're taking that. It's really about thinking about using it responsibly. Now, the good news about light emitting diode technology is they can be controlled. You can control both the direction of them through clever optics, you can control this underlying spectrum, the sort of colour, quality of the light, and you can dim them down and turn them off very quickly when they're not needed. So they have tremendous promise when they're used carefully. But if they're used without thought, the impact on the natural world can be tremendous.
22:36 - Policies to protect dark skies
Policies to protect dark skies
Martin Morgan-Taylor, DeMonfort University
How can responsible light use be put into practice? Chris Smith spoke with Martin Morgan-Taylor, associate law professor at De Montfort University and expert on light pollution legislation...
Martin - Well, this is a good one. Really what we need to do is we need to make sure that people, ordinary members of the public, can see that there is a problem that affects them in their day-to-day life, something that matters to them. And also, that we can see that regulators can see that it's an issue that's actually worth regulating. And the two are intertwined because regulators won't act if they believe that the public don't see it as something that's a vote winner. So really what you've been showing here is great because you've been showing that light pollution is not just about the loss of the night sky, and that's how it's traditionally been couched in terms. Really what we're seeing is it's something that can harm human health, it's something that can harm animal health, it can also even disturb plant life, but it can also amount to a waste of electricity. And the waste of electricity is produced from fossil fuels, which is a waste of carbon emissions. And really what we could do with is further research that really pinpoints where lighting really makes a difference? Now there's been some research that's been done, but I think what we need to do is to drill down and get this in further granularity, because today people are frightened of knife crime.
Chris - You are a legal expert, do we have a sort of threshold or are we at risk here because we have no case or it's hard to build a case because we're saying, well, we don't know where the line is. What's light pollution? How bright does something have to be before we consider it is causing light pollution? Or is it just a subjective thing where a person says, well, that's disrupting my sleep? Is that not part of the difficulty here that we haven't got a set of standards that people agree on what is light pollution. That's not, that's not all right, that is.
马丁-是的。我当然说光pollution is the sum of all of the negative effects that can be caused by light at night. Now you're right because there's several ways that you can go about this. Really it's a combination of all of what I'm about to say which I think would actually work quite nicely. We need to be proactive and preventative. We need to try and stop as much of the problem arising in the first place. So in other words, stopping the sales of a great amount of poor lighting or lighting that's often misused. So very bright consumer domestic flood lighting, so-called security lighting, is a good example because there's no research study that says that it actually deters criminals. So all people are probably doing is wasting their own electricity bill and potentially disturbing the sleep of neighbours or the ecology or the loss of the night sky. So trying to stop things in the first place is a good place to begin. And then if you're trying to deal with a problem once it's arisen, really you need enforcement bodies to see that light pollution is something that's genuine. And if you've got a set of metrics, in other words, a table that says this amount of light is okay, but that isn't, now there are some guidance documents here that will give tables for lighting. So again, that helps. But really what we need is public understanding. Light, yes, it can be a great help for us. But really the more the light, the better is a bit of a myth. Lighting to a level is helpful rather than lighting over and above that. And it's also making sure that the light goes where it's needed, where it's intended. So if we've got regulation to make sure that light is shielded to stop it from shining into the night sky, it's like having half of your radiators sticking out of your windows when you're trying to keep your house warm in winter?
Chris - Martin, can I ask you, are there any countries which are doing this particularly well or better than we are so that we can look at what they're doing and what seems to work? Is it just down to public policy and what the public think and making a health issue to get people interested? Or are there other ways to make this happen?
马丁-法国是一个很好的例子。他们已经had some fresh legislation that just came in a few years ago, and really it's couched in terms of trying to save energy and also to help the environment. But certainly to actually help people with the money in their pockets. So what we have got is curfews. So this is really simple and straightforward to enforce. Lights need to go off after a certain time at night. So this is internal as well as external lights, because so many times we see skyscrapers, we see office blocks with all of the lights on all night long. And you think, I mean, really why? So what you have got is a rule that certain lighting, most lights, need to go off after a certain time. And then we've got controls over blue lighting, which is trying to limit the problem of blue light at night. We've also got controls of sky beams, bright advertising lights and things of this nature. So if you've got a regulatory system that's trying to stop bad lighting going up in the first place, to have relatively straightforward principles such as curfews - the light is on or it's off, it's pretty straightforward, you don't need a light metre to see whether or not it's over and above the level of light that's permitted - but then there are other countries such as Korea, which have got metrics where you've got a table that really is where you are allowed this much light, but you're not allowed more than that.. You do need a light metre, but then that's trying to limit things to particular set standards. Whatever method you use, you're going to need the buy-in of the members of the public and also the enforcement bodies.
克里斯-将市场力量在某种程度上骑你r rescue on this one because I think with the cost of living crisis, there's a big drive now to endow houses with smart metering. People are very energy conscious about the climate as well at the moment. Will all this perhaps come together and motivate people to think, well hang on, that's energy. If I cut those lights down, this will help. Because we've got an enormous housing stock with lots of old fashioned architecture and old fashioned specifications and we are in the dark ages with our insulation and so on. It's going to take years for all that to catch up. Are we not at risk if we start saying, well, we'll legislate, but it doesn't apply to older properties? It's going to take a hundred years before we're up to date.
Martin - Yeah, it's a difficult one. Certainly your first point there about market forces, if you actually get your customers, your public, your business to recognise that overlighting is just a waste of energy, it's a waste of carbon emissions, it's bad for the environment, it's bad for everything, then you're going to end up with a reduced demand for that particular type of lighting. So that's good, but yet you still then will have the existing lighting stock that's in place. But I think it's probably going to be unfortunately necessary that people are allowed to phase out old light types. We need consumers to realise that lighting and energy saving is all part of the same thing and external lighting is still part of this energy saving.
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