Tens of thousands of lakes were dying, their lifeless waters clear to the depths. Public statues were eroding, their features eaten away by acid falling from the skies.
No more.
Thirty years after Canada and the United States signed a treaty on reducing acid rain, the deal has become a landmark — and a guidebook — on how nations can work together to solve environmental problems.
"It's an example," said John Smol, a biologist at Queen's University in Kingston, Ont. He did some of the early scientific research that connected the dots between emissions and empty watersheds.
"It showed you can get together and deal with a transboundary problem. You can set realistic targets. It really was a success story."
The trouble was sulphur and nitrous dioxides from industrial smokestacks and cars combining with atmospheric moisture.
The treaty signed March 13, 1991, by Canadian prime minister Brian Mulroney and U.S. president George Bush changed all that.
A quarter of a century later, Canadian emissions of sulphur dioxide had decreased by 69 per cent. Nitrogen dioxide had fallen by more than 25 per cent. Emissions continue to fall.
It wasn't easy, said Elizabeth May, a Green party MP and former party leader, who was then a senior policy adviser to Mulroney's Progressive Conservative government.
"Just as we have false stories about climate change, we had false stories about acid rain," she said. "At one point, (former U.S. president) Ronald Reagan said acid rain was caused by ducks.
"You had a strong lobby from the coal-producing states. You had a strong lobby in Canada. They weren't feeling very co-operative. So where do you start?"
She gives a lot of credit to her old boss.
"Mulroney put acid rain at the top of every bilateral meeting," she said.
"It was quite extraordinary how a plan came together. Often in politics, it's quite random. Something goes wrong, someone's in the right place at the right time.
"But this was a strategy that from its inception worked perfectly. You need leadership from the top and you need to demonstrate you're serious.
"We haven't seen political will like that in decades."
Parallels with climate change are obvious, said Smol.
"It went through the same steps. It went from 'there is no problem' to 'there is a problem, but it's not our fault' to 'there is a problem, it is our fault, but it's too late to do anything.'"
But a deal was achieved.
"It is one of those rare environmental victories," said Keith Stewart of Greenpeace. "We developed a treaty, implemented it and largely solved that particular problem.
"Industry stopped pumping money into lawyers and lobbyists and started hiring engineers, and they were able to solve the problem in relatively short order. The economy did not fall apart."
Comparisons between acid rain and climate change can go too far, said Nelson Wiseman, a University of Toronto political scientist.
"The challenge is quite different," he said. "Climate change is a global problem. Canada and the U.S. can agree to anything they want, climate change will continue."
Wiseman also suggested politicians of different stripes were able to work together more easily back then.
"Things maybe are more polarized now than they were 30 years ago."
The relationship between Mulroney and Bush was extraordinarily close. Mulroney gave the eulogy at Bush's funeral.
"I don't think you can say that about (Prime Minister Justin) Trudeau and (President Joe) Biden," Wiseman said.
Still, said May, there's a window for the two countries to make progress on this generation's environmental challenge, just as they did on acid rain.
"We have a real opportunity with the Biden administration," she said.
"Think about COVID. The kind of response we should be seeing for the climate crisis is now visible in how governments are responding to the COVID crisis.
"Is it possible that we could respond to the climate crisis with the same seriousness of purpose that we responded to acid rain? Absolutely."
Just look at the results, said Mulroney.
"Interesting thing about acid rain," he told The Canadian Press.
"You probably haven't heard very much about it anymore. It doesn't exist anymore because we got rid of it."
This report by The Canadian Press was first published March 12, 2021.
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Bob Weber, The Canadian Press