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Good afternoon, and welcome to Globe Climate, a newsletter about climate change, environment and resources in Canada.
The salt used to keep winter roads safe is endangering municipal water systems – and the environment. Below, we take a closer look at the briny issue and why there hasn’t yet been a desalination solution.
Now, let’s catch you up on other news.
Noteworthy reporting this week:
- Oceans: Canada shores up commitment to protect high seas with UN treaty set to become law
- U.S. courts: Trump administration illegally blocked billions in clean energy grants to Democratic states, court rules
- Reforestation: Manulife taps Vancouver-based veritree’s technology for its reforestation program
- Mining: Ontario fast-tracks Canada Nickel’s Crawford mine permitting in response to U.S. trade war
- Weather: What do the new colours for weather alerts mean? What you need to know
- Resources: Carney meets with coastal First Nations in B.C. to talk resource development
A deeper dive
Workers attempt to keep the sidewalks clear during a snowstorm on Boxing Day in Toronto last month.Sammy Kogan/The Canadian Press
A salty problem
For this week’s deeper dive, a closer look at the salt we use to clear our winter roads, and the effect it has on the environment.
Calgarians are back to using their bathrooms without worrying that a simple flush of the toilet could push the city’s ailing water system toward another catastrophe.
The failing portion of the Bearspaw South Feeder Main was supposed to last 100 years, but 50 years into its service life investigators found that chloride had caused hydrogen embrittlement and stress corrosion in the wires. The same chemical used to keep the city’s winter roads safe was endangering its water system.
Every year, Canada scatters around seven million tonnes of sodium chloride on public roads, writes Patrick White. That’s enough to fill a line of dump trucks stretching from Vancouver to Toronto, and it likely makes us the biggest per-kilometre salt users in the world, according to a 2020 Norwegian study.
The Canadian Council of Ministers of the Environment considers chloride in water safe for aquatic life as long as it doesn’t exceed 120 milligrams a litre. But waterways around big Canadian cities routinely measure more than 10 times that threshold.
Zooplankton are especially sensitive. Because they eat algae and, in turn, are eaten by small fish, they are a vital link in aquatic food chains, converting algal growth into animal energy.
“Is that where we want to go – lakes that are full of algae and lacking in diversity?” said Shelley Arnott, a Queen’s University biology professor specializing in aquatic ecology. Her research has found that organisms in many bodies of water start to show adverse effects at chloride levels of between 5 and 40 mg/L, suggesting Canada’s guidelines could be too forgiving.
Road salt is damaging infrastructure and harming aquatic life in and near some of Canada's major cities.Fred Lum/The Globe and Mail
Road authorities are experimenting with an array of food-based alternatives, including coffee grounds, cheese brine, pickle juice and beet juice, which Arnott has found can be more toxic than salt.
Yet for all the reduction efforts, salt continues to accumulate in the environment. Chloride levels in Lake Simcoe, for instance, have increased steadily by about 0.7 mg/L a year since the 1970s despite reduction programs throughout the region.
Joe Salemi is executive director of Landscape Ontario, an industry group representing snow-removal companies. He says governments could focus on public education, since there are no simple alternatives. But overall, he says the outlook for eliminating road salt is bleak.
“It’s a wicked problem. There’s no clear solution.”
What else you missed
- French firm, South Korean partner hope to develop offshore wind projects in Nova Scotia
- Chilean wildfires leave at least 18 dead, force thousands to flee
- Winter storm shuts schools across the Maritimes and causes power outages in Nova Scotia
- Leaving the Arctic is tough, but returning to ‘civilization’ is much harder
- Why I’m heading back to Montego Bay after Hurricane Melissa
Opinion and analysis
No, Indigenous people are not coming to take Canadians’ homes
The Cowichan decision reflects the Proclamation and other court decisions, upholding the fact that Canada operates in partnership, and is built on relations with Indigenous peoples. This is why the decision is not a threat – it is a reaffirmation.
— Tanya Talaga
Green Investing
How Wall Street turned its back on climate change
Six years ago, when Larry Fink, the chief executive officer of BlackRock, called to address climate change starting with trillions of dollars managed by his firm, it was the unofficial kickoff of a movement. Nearly every major financial institution was soon pledging to reduce emissions, joining high-minded alliances designed to phase out fossil fuels and promising to support clean energy.
Today, many of those Wall Street institutions have walked back or abandoned their commitments. These dynamics will be on full display this week, as Fink, now co-chair of the World Economic Forum, welcomes U.S. President Donald Trump to Davos, where climate issues have taken a back seat to artificial intelligence and geopolitics.
Photo of the week
Volunteers arrange old Christmas trees on a sand dune in Carcans, France, earlier this month. The work is part of an ecological engineering project managed by the National Forest Office to combat coastal erosion. The trees trap windblown sand and promote the growth of native vegetation such as marram grass and sea spurge, natural dune-stabilizing plants that protect the coastline from rising sea levels and increasingly frequent storms.PHILIPPE LOPEZ/AFP/Getty Images
Guides and Explainers
- Want to learn to invest sustainably? We have a class for that: Green Investing 101 newsletter course for the climate-conscious investor. Not sure you need help? Take our quiz to challenge your knowledge.
- We’ve rounded up our reporters’ content to help you learn about what a carbon tax is, what happened at COP29 and just generally how Canada will change because of climate change.
- We have ways to make your travelling more sustainable and if you like to read, here are books to help the environmentalist in you grow, as well as a downloadable e-book of Micro Skills – Little Steps to Big Change.
Catch up on Globe Climate
- Exoplanet exploration
- In 2025, glacier loss reshaped landscapes
- Canada’s Coast Guard put to the test
- Arctic warmth, political chill