Science·What on Earth?

Reducing light pollution has numerous benefits for the environment

In this week's issue of our environment newsletter, we look at why light pollution is a 'stressor' on the planet and why poppies are a symbol of ecological renewal.

Also: Why poppies are a symbol of Remembrance Day - and ecological renewal

White text against a semicircle made of lines and blue and green stripes
(Sködt McNalty/CBC)

Hello, Earthlings! This is our weekly newsletter on all things environmental, where we highlight trends and solutions that are moving us to a more sustainable world. (Sign up here to get it in your inbox every Thursday.)

This week:

  • Reducing light pollution has numerous benefits for the environment
  • The future of natural gas in the U.S.
  • Why poppies sprouted on Europe's battlefields

Reducing light pollution has numerous benefits for the environment

(Christopher Kyba)

Typically, when people think about pollution, it's a question of air quality. But there's another kind that poses a threat to humans and animals: light pollution.

Multiple studies have shown that the abundant nighttime light found on streets and in buildings can adversely affect animals — altering migration patterns — as well as insects. There's also been increasing evidence that it can disrupt the circadian rhythm of humans, an important biological process that regulates our sleep cycle.

For these reasons, many people have advocated finding ways to reduce light pollution. But it's not always clear which sources are creating the most light. 

A recent study published in the journal Lighting Research & Technology examined streetlights in Tucson, Ariz., over a period of 10 days. The city dimmed the lights at 1:30 a.m. every day during that period. Using satellites to monitor the light that seeped upward into space, the study found that light pollution dropped by just 13 per cent, suggesting that there are other sources of light that are causing pollution. (They suspect it could be things like billboards, car dealerships and parking lots.)

The importance of the study is to illustrate that cities can conduct similar research to determine ways to reduce light pollution from sources other than streetlights, said Christopher Kyba, a scientist with the GFZ German Research Center for Geosciences in Potsdam, Germany, and lead author of the paper. Kyba acknowledges more research is needed to determine exactly where that excess light pollution comes from, something that he hopes to examine in another study.

Finding out more about this could help cities design strategies to address the issue. But there's another benefit to reducing light pollution: less light means less energy production.

"All the light that we have is paid for by someone, and basically at the end of the day, it's us," said Kyba.

"We need the energy to produce all that light," he said, which could mean building environmentally unfriendly structures like a nuclear power plant or a hydro dam. "Or you have to burn coal or something and we all know that's bad for all kinds of reasons."

Kyba said, "anything we can do to reduce energy consumption is basically alleviating this other problem associated with energy production."

Robert Dick, former chair of the light pollution abatement committee at the Royal Astronomical Society of Canada, said light pollution should concern everyone. 

"[People] should care about light pollution the same way they should care about reducing environmental pollution and designing cities to be sustainable," he said. 

"Light pollution is one of those extra stressors you put on the environment." 

Nicole Mortillaro

(Full disclosure: Nicole Mortillaro is the editor of the Journal of the Royal Astronomical Society of Canada and the former head of the Toronto chapter of the International Dark-Sky Association.)

Reader feedback

In response to Yvette Brend's story on the Federal Court's dismissal of a youth-led climate change lawsuit against the government, Kathy Kilburn had this to say:

"The Federal Court's refusal to hear the young people's lawsuit is another brick in the wall of denial, obfuscation and bureaucratic drivel that is helping to doom our planet and its passengers," wrote Kilburn. "Disgusting. Keep slugging, kids — this old foop is behind you! My generation should have done SO much better."

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Old issues of What on Earth? are right here.

There's also a radio show! Tune in to What On Earth this week for a look at the push to develop small modular reactors as Ottawa seeks to achieve net-zero emissions. But opinions are divided, and some warn SMRs are a dangerous distraction from real climate action. What on Earth airs Sunday at 12:30 p.m., 1 p.m. in Newfoundland, and is available any time on podcast or CBC Listen.

The Big Picture: The future of natural gas in the U.S.

In a push to energize indecisive voters in swing state Pennsylvania during the final weeks of the U.S. election campaign, President Donald Trump warned that Democratic candidate Joe Biden would ban fracking (hydraulic fracturing), which has provided a lot of jobs to the region. Biden vigorously denied he would do any such thing. Setting aside the fact that the process of fracking to extract gas has become increasingly unpalatable to Pennsylvanians, recent analysis shows that gas is losing its hold on energy generation in the U.S. Once touted as a "bridge" fuel in the transition to a low-carbon economy, natural gas is fighting a losing battle against renewable energy sources like wind, solar and geothermal. A recent analysis by the investment firm Morgan Stanley projected that by 2028, renewable energy will overtake natural gas in U.S. power generation (as measured in gigawatt hours).


Hot and bothered: Provocative ideas from around the web

  • The New York Times has a well-earned reputation for producing compelling interactive features. This one on Alberta's abandoned oil wells is no different. It's premised on this chilling fact: The nearly 100,000 inactive wells "are unlikely to be switched on ever again but have not yet been decommissioned. No one knows how many are leaking methane and other pollutants."

  • Not only is Glasgow preparing to host the COP26 climate summit next year, but Scotland is close to reaching a lofty goal of generating 100 per cent of its power from renewable energy, primarily wind. Some people have even taken to calling Scotland "the Saudi Arabia of renewables."
  • Australia could soon be home to a 10-gigawatt solar farm spanning 12,000 hectares. Not only would that make it the biggest in the world, but two-thirds of the power is set to be exported to Singapore — 4,500 kilometres away — via "high-voltage direct current undersea cable."

Why poppies sprouted on Europe's battlefields

(Guillaume Souvant/Getty Images)

As Remembrance Day approaches, many of us will be pinning a poppy to our jacket or lapel. 

The red flower became a symbol of remembrance because it sprouted over the battlefields of Europe after the First World War. John McCrae's well-known 1915 poem In Flanders Fields describes poppies growing between the crosses of fallen soldiers. 

But of all plants, why were poppies the first to grow there? And why did they grow in such abundance? Turns out it's a case of environmental renewal. 

"A poppy is one of those pioneer, ruderal plants," said Egan Davis, principal instructor for the horticulture training program at the University of British Columbia's Botanical Garden. "Their role is to basically patch [a] site after major disturbance." 

That could be a natural disaster, like a flood or forest fire, or, in the case of European battlefields, ongoing fighting that wiped out most trees and vegetation. 

"The seeds are there, waiting," Davis said. He referred to it as a "seed bank" — seeds lying dormant in the soil, ready to germinate. When the disaster has passed and all other plants have been wiped out, those seeds have the space to grow. 

"What's really beautiful about that system is that at any point, where there's a big disturbance and everything crashes, it just basically kickstarts," Davis said. 

Poppies play the role of that common first plant in parts of Europe. Davis said that in much of Canada, fireweed is the first to sprout after forest fires. 

Those pioneer plants that grow after a disaster are "usually the most glorious," he said. "That's what their role is: basically flower like crazy." 

He said that once the poppies come up, bigger plants and shrubs will start to return to rebuild the natural habitat of the area. With this in mind, Davis said he sees the poppy as a sign of renewal. 

"I can't imagine anything more disturbing to the earth and to human society than war," he said. "But when poppies germinate after the war, that's a sign of promise."

— Menaka Raman-Wilms

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Editor: Andre Mayer | Logo design: Sködt McNalty

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