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Bring Back the Night: An Article on light pollution

In this two-part piece on the implications of light pollution, and how to overcome the challenges associated with them, Parth Bhargava and Ishita Gupta shed light on an often overlooked environmental issue.

Part 1: The Issue - Parth Bhargava

Did you know that one-third of the population of Earth has never seen the milky way with their naked eye? America has it worse, with over 80% of Americans never seeing the milky way without astronomical instruments. These days, we are unable to view the vast majority of stars with the naked eye in many heavily populated areas due to excessive light pollution. This artificial light not only impairs our ability to observe the night sky but also has many adverse effects on all other aspects of our ecosystem, from our health to our energy consumption.

Light pollution is caused by the immoderate, unnecessary use of artificial lights such as unshielded light fixtures and forms of outdoor lighting. Poorly designed residential, commercial, and industrial outdoor light fixtures emit more than 50% of their light towards the sky or sideways. In many instances, only about 40% of the light emitted actually illuminates the intended area. This skyward light creates an aura of light above major cities such as Los Angeles and Singapore called skyglow, which is the orange haze beyond the horizon that often illuminates the night sky. All aspects of light pollution have consequences in the astronomical world, where side-effects of light pollution can obscure the view of faint celestial bodies, even with refined instruments. However, the impact of light pollution is so extensive that there are repercussions not only for astronomers but also for wildlife ecosystems and the environment.

A variety of ecosystems suffer from light pollution, but perhaps most famously sea turtles. When baby sea turtles hatch, they find their way towards the ocean by following the horizon. However, as a result of light pollution, millions of hatchlings die every year after wandering away from the ocean towards the city lights.

Among the other ecosystems affected by light pollution, birds that migrate or hunt at night and navigate by moonlight are especially susceptible to the effects of light pollution. Artificial light sources can overwhelm natural light sources, causing birds to fixate on the artificial lights. This results in birds straying from their intended migration route. These birds are also known to collide with buildings and other structures due to their bright lights. In North America alone, 100 million birds die annually due to light pollution.

The impact of light pollution additionally has dire consequences on the environment, from increasing carbon dioxide levels to inhibiting the levels of chemicals that break down emissions during nighttime. Although counter-intuitively, light pollution is responsible for the production of 12 million tons of carbon dioxide annually, which would take over 700 million trees to absorb.

Furthermore, in the darkness of the night, a naturally occuring chemical called the nitrate radical forms, which breaks down factory and vehicle emissions; a process that prevents these emissions from becoming harmful irritants like smog and ozone pollution. This process only takes place at night as sunlight destroys this chemical. Although the light produced by artificial lights at night is significantly less than that of sunlight, the artificial light slows down the process by which the emissions are broken down.

Part 2: The Solution - Ishita Gupta

On May 30th 2019, SpaceX launched 60 satellites that could change the face of internet communication as we know it. The satellites, which aimed to bring unobstructed internet access to every single part of the world, also aimed to do so while avoiding the issue of space junk. Flying at the comparatively low altitude of 550 kilometres above the surface of the earth, they were low enough to get pulled down by earth’s atmospheric drag at the end of their lifetimes. But by attempting to solve the issue of one aspect of space pollution, they created another, completely unforeseen one.

Astronomers around the world began to notice that their views of the night sky were now disturbed by bright streaks of light. Many worried that any more such satellites would be too bright, obscuring the galaxies around our solar system from human eyes for years to come, not only in our cities but even in the most remote parts of the planet. However, the big question on everyone’s mind was ‘Who would oversee the regulation of a project like Starlink?’. Who is responsible to ensure the darkening of our skies in the face of rapid industrialisation and innovation that threatens the night sky as we know it?

This issue isn’t limited to the case of SpaceX’s Starlink Satellites, but extends to all aspects of the issue of light pollution on earth today. The lack of a concrete framework or an international body overlooking concerns about light pollution, the issue of policy surrounding light pollution seems immensely complex. The seventeen UN sustainable development goals have no mention of light pollution. Light pollution isn’t glimmering, not shiny enough for politicians to talk about in their electoral speeches. There simply isn't enough attention, enough light shed on this issue.

But it doesn’t always have to be like this. Countries like Croatia are leading the path to darker nights, through lighting guidelines that are the most advanced in the world.

The Croatian policy on light pollution is comprehensive, with regulations on outdoor lighting design and electrical consumption. It covers a range of aspects concerning light pollution, mandating lights with temperatures below 2200k in ecologically sensitive areas and screening of interior lights so they don’t spill outdoors when unnecessary. Terms are extensively defined, making the policy clear and precise. The policy combines recommendations from research studies all over the world, the same research that recommends regulations on decorative lighting, and the implementation of ‘smart lighting’, lighting that responds to changes in activity and light levels in surround areas, only turning on when it's truly needed, and sensors automatically turning it off when there is no one around to benefit from its use. The suggested fixes are simple but effective, replaceable in all developing and developed nations. However, there is one key takeaway, one unassumingly obvious policy that often gets overlooked due to its simplicity.

It states that all lighting plans require submission for approval before construction.

It seems so obvious, yet it highlights the fatal flaw in the way that we approach light pollution. Unlike the myriad of environmental issues that present themselves today, light pollution is largely avoidable, and mostly a question of planning and minimising efficiency. If governments take an active role in ensuring our cities are designed smarter, keeping in mind from day one how to prevent unneeded light from leaking into our ecosystems, limiting lighting strategically only necessary areas, we can turn off the pollution.

Light pollution is avoidable, and it's largely a question of planning and regulation. Planning and regulation that the governments and international organisations like the UN can no longer ignore, but should rather, come together and make an important developmental goal. The solutions are there, but what's lacking is the implementation.

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Parth Bhargava is the writer of a blog called The Physics Behind, in which he explores various physical phenomena like black holes, gravitational waves and exoplanets. He enjoys all things space-related, and would love to meet people who think the same way. If you are interested in more pieces like this, or simply want to check out his blog, visit https://thephysicsbehinditall.blogspot.com/ !!!