**This episode originally aired April 22, 2019.

Forty years ago, nickel mines and smelters around Sudbury, a relatively small city in northern Ontario, had created one of the most dramatic examples of environmental devastation in the history of our planet.

The nearby landscape appeared dead and blackened.

Today, Sudbury boasts some of the cleanest air of any city in Ontario. Formerly acidified lakes — and there are 330 substantial lakes within the city limits alone — have come back to life. The surrounding countryside is now green and forested.

"The big push at the beginning was liming large tracts of land," explains Tina McCaffrey, supervisor of Greater Sudbury's 're-greening' program. Once the lime has neutralized the acids in the soil, workers plant grass seeds and, later, tree saplings.

The process of diversifying and restoring the ecosystem takes decades, and is still underway.

"I get a new crew every year," says McCaffrey. "I need to teach them and show them what difference it's going to make. I take them out to site that's been limed the previous year. They can see the actual line where the regreening stopped. It is like night and day. It is green and it is black."

Dr. Nadia Mykytczuk is an assistant professor at Laurentian University's School of the Environment. 1:00

Paul Kennedy chose the environmental success story of Sudbury as one of his final presentations as host of IDEAS. Paul retires at the end of the 2018-19 season. See below for his reflections on the profound effect his recent Sudbury visits had on him.

Paul Kennedy's Notebook There's no way to convey how much the greening of Sudbury has meant to me. It's almost impossible for me to believe it myself. When I returned to Toronto last fall, after an exploratory two-day visit, I started to share my newfound environmental optimism with everybody I knew. In fact, I was so excited that I almost stooped to stopping total strangers in the street, just to spread the good news. "Sudbury is green!" After years of watching me sink into deeper and deeper despair, some of my closest friends expressed sincere concerns about the state of my mental health. "What sort of magic mushrooms were they feeding you in Sudbury?" asked a long-time colleague. "Do you know if any of your ancestors were prone to instantaneous and inexplicable changes of personality, or sudden radical shifts in outlook or attitude?" Since my friend is a medical doctor, her questions caused me momentary concern. The evidence is overwhelming. Scientists at Laurentian University, some of whom have been involved in the regreening project from the very beginning, measure the initiative's success by comparing the acidity of lakes, or the vitality and abundance of vegetation and wildlife. There has been unprecedented progress on all fronts. Even multinational corporations involved with mining operations came to agree that going green doesn't require their business to fall into the red. I tend to be a knee-jerk optimist on almost every issue, but the future of our planet can seem almost overwhelmingly difficult — too big, too complicated, too divisive. For me, Sudbury is an indication that we aren't going to lose. Climate change is the biggest and most crucial challenge we face. There is hope. Thank you, Sudbury.

Guests in this episode:

Nathan Basiliko holds a Canada Research Chair at Laurentian University. He is working to develop methods of sequestering carbon dioxide within the recently re-greened and recovered landscape surrounding Sudbury.

holds a Canada Research Chair at Laurentian University. He is working to develop methods of sequestering carbon dioxide within the recently re-greened and recovered landscape surrounding Sudbury. Jim Bradley grew up in Sudbury, and was Ontario's Minister of the Environment from 1985 through 1990, during difficult negotiations with the U.S. government for a new cross-boundary Clean Air Act. He is currently the elected Chair of the Regional Municipality of Niagara.

grew up in Sudbury, and was Ontario's Minister of the Environment from 1985 through 1990, during difficult negotiations with the U.S. government for a new cross-boundary Clean Air Act. He is currently the elected Chair of the Regional Municipality of Niagara. Dave Courtemanche first heard about the greening of Sudbury when he was in elementary school. With his classmates, he carried huge sacks of lime out onto the black rocks. He served a term as Mayor of Sudbury, and is now Executive Director of the City of Lakes Family Health Team.

first heard about the greening of Sudbury when he was in elementary school. With his classmates, he carried huge sacks of lime out onto the black rocks. He served a term as Mayor of Sudbury, and is now Executive Director of the City of Lakes Family Health Team. John Gunn holds the Canada Research Chair in Stressed Aquatic Systems at Laurentian University, where he also runs the Living with Lakes Centre.

holds the Canada Research Chair in Stressed Aquatic Systems at Laurentian University, where he also runs the Living with Lakes Centre. Bill Keller is Director of Climate Change and Multiple Stressor Aquatic Research at Laurentian University.

is Director of Climate Change and Multiple Stressor Aquatic Research at Laurentian University. Bill Lautenbach first arrived im Sudbury in 1975. He is currently retired, having served for many years as a City Planner for the Greater Sudbury Region.

first arrived im Sudbury in 1975. He is currently retired, having served for many years as a City Planner for the Greater Sudbury Region. Tina McCaffrey grew up in Sudbury, and has lived there for her entire life. She is currently the Supervisor of Sudbury's Re-Greening programme.

grew up in Sudbury, and has lived there for her entire life. She is currently the Supervisor of Sudbury's Re-Greening programme. Bob Michelutti started working at Falconbridge Mines in 1970. He retired from his position as Superintendent of Environmental and Health Services in 2000.

started working at Falconbridge Mines in 1970. He retired from his position as Superintendent of Environmental and Health Services in 2000. Nadia Mykytczuk holds an Industrial Research Chair at Laurentian University. Her 'mission' is to transfer the lessons learned in Sudbury to the rest of the world, through an online university course called "Environmental Remediation: Global Lessons from the Sudbury Story".

holds an Industrial Research Chair at Laurentian University. Her 'mission' is to transfer the lessons learned in Sudbury to the rest of the world, through an online university course called "Environmental Remediation: Global Lessons from the Sudbury Story". David Pearson arrived in Sudbury in 1969 as a geologist. He was one of the major forces behind the creation of Science North. He now works on science communication, and with Indigenous groups on James Bay.

arrived in Sudbury in 1969 as a geologist. He was one of the major forces behind the creation of Science North. He now works on science communication, and with Indigenous groups on James Bay. Michelle Reid teaches Science Communication at Laurentian University. She is one of the creators of Environmental Remediation: Global Lessons from the Sudbury Story.



Laurentian University has created an online university course about environmental remediation based on the Sudbury story.

**This episode was produced by Paul Kennedy & Tom Howell.