Long-term Statistics Canada research shows cities across country losing green space
CBC
Joni Mitchell was right — they really are paving paradise and putting up parking lots.
Statistics Canada's first survey of urban green space shows that, just as the singer-songwriter warned, cities across the country are getting greyer and browner.
"We did a see a decrease over the time period we looked at," said Jennie Wang, who helped prepare a massive report from the federal agency released this month on human activity and the environment.
Statistics Canada used satellite imagery to estimate the amount of green space in Canadian cities — parks, urban trees, even backyards and lawns. The data has existed for years, but it was used for this purpose.
"[We're] getting a sense of the condition of vegetation in urban areas," Wang said. "It's the first time we've done that."
The researchers looked at 31 urban centres of various sizes across the country. They compared satellite images from 2001, 2011 and 2019.
They found about three-quarters of large and medium-sized cities were less green in 2019 than they had been 20 years earlier.
"You end up seeing less green as you walk down the street," Wang said.
Big losers include cities such as Kelowna, B.C., which went from nearly three-quarters green to less than half. Milton, Ont., went through a similar drop, as did Winnipeg.
Toronto, Montreal, Vancouver, Calgary and Edmonton all lost green space. Saskatoon and Regina were among the few that gained.
Urbanization is a big driver of green space loss, said Wang. Milton grew by 350 per cent over the course of the study and Kelowna's population grew from 150,000 to 223,000.
Other factors such as drought or insect infestations also play a role. Winnipeg's losses, for example, were exaggerated by the emerald ash borer.
But the losses are real, said Wang, and have real implications.
"There's been studies showing the many benefits of vegetation," Wang said. "There's reductions in energy use, trees remove air pollutants. There's also research looking into human health benefits."