Calgary has added more than 350,000 people over the past two decades, most of them housed in sprawling new neighborhoods. Jeff McIntosh/The Canadian Press
If urban green spaces are the lungs of the city, Calgary risks becoming wheezing.
The prairie city is struggling to increase its modest tree cover, with budget issues hampering long-term plans to double the crown. And new federal data shows Calgary — which declared a climate emergency in November 2021 — has seen the biggest decline among major Canadian cities in how green it is overall.
The findings, which were published in November by Statistics Canada, are based on an analysis of the color of satellite images during the summer. The study used 2000 to 2004 as a base period and looked again from 2018 to 2022. During that time, Calgary’s total land area increased from 54.1% green to 37.6%.
This 30.5 per cent decline is roughly double the 13.3 per cent decline in the greenness of Canada’s major urban centers as a whole over the same period. The two-decade downward trend comes amid accelerating suburban sprawl — and even as municipal leaders across the country express growing concern about climate change.
Urban greenery diminishes with time,
the top five largest urban population centers
Percentage of land area that is classified as green
MURAT YUXELIR / THE GLOBE AND THE POST,
SOURE: STATISTICS CANADA
Urban greenery diminishes with time,
the top five largest urban population centers
Percentage of land area that is classified as green
MURAT YUXELIR / THE GLOBE AND THE POST,
SOURE: STATISTICS CANADA
Urban green is decreasing over time, the top five largest urban population centers
Percentage of land area that is classified as green
MURAT YUKSELIR / THE GLOBE AND POST SOURCE: STATISTICS CANADA
And experts say that reduction creates a host of problems.
Urban green spaces provide crucial benefits. It removes and stores carbon. It can help reduce environmental heat, improve flood protection and provide habitat for birds, pollinators and other biodiversity. It provides a boost to our mental health. The presence of roadside trees has been shown to increase safety by subconsciously causing drivers to slow down.
City staff in Calgary believe the biggest cause of the decline is the development of former green lands within the city limits. The city has added more than 350,000 people in the past two decades, most of them housed in sprawling new neighborhoods.
Matthew Sheldrake, the city of Calgary’s acting strategy manager for growth and change, said the city has been doing better since 2009 at encouraging intensification, although that type of housing still represents a small portion of new residences. He says a more comprehensive approach may be needed to balance the goals of meeting housing demand and protecting the environment.
“Sometimes they conflict … we have policies for both and sometimes we have to make tough choices,” Mr Sheldrake said.
“I have one myself [contributed to] reports we wrote where there was almost a cognitive dissonance in the report where we both recognized what we were trying to do in terms of affordability and the supply of new housing and were also clear about what we were doing as it related to greening and climate change.”
Calgary is not alone in struggling with such controversies.
Toronto has declared a climate emergency in 2019, but the city is still rebuilding an elevated highway on its waterfront. generating a huge amount of emissions. Vancouver has a climate emergency plan, but it only allows for very modest density in much of the city, forcing people to live farther away and lengthening their commute.
At the same time, the United Nations has declared 2021 to 2030 the “Decade of Ecosystem Restoration.”
Ian Leahy, vice president of urban forestry at the nonprofit American Forests, said the savings in public health, ecosystem services and other benefits mean that every dollar invested in trees pays for itself threefold.
“As our cities are warming, our climate is warming, that’s becoming apparent [trees are] becoming basically life-saving infrastructure,” he said.
On this front, Calgary was lagging behind. The city has a modest 8.25 percent tree cover, which has been slightly reduced since the stormy bad weather of 2014. The plan is to double the canopy by 2060, which would require planting 3,500 trees a year to maintain the existing stock plus another 4,000 for expansion.
However, budget cuts in 2019 prevented staff from reaching this goal. Instead, the focus turned to increased pruning in an attempt to make the urban forest more sustainable. This year’s budget includes $8 million over four years for habitat restoration. This will fund 2,100 new trees a year – around half the number needed to implement the canopy expansion plans.
“Society usually thinks of the landscape as something to be added at the end, that it’s more of a nice-to-have than a vital service,” said Bev Sandalak, a professor in the Faculty of Environmental Design at the University of Calgary.
Calgary’s 16.5 percentage point drop in greenness, as measured by Statistics Canada, was a much larger drop than in nearby Edmonton — where overall greenness dropped 11.8 percentage points over the same period. Declines in other major Canadian cities ranged from a low of 9.3 percentage points in Montreal to 14.2 percentage points in second-ranked Vancouver.
The agency pulls its data from satellite images using a comparison called the Normalized Vegetation Difference Index to calculate how literally green areas are. The City of Calgary said it was not involved with Statistics Canada in the survey and was not aware of it until the results were released.
Source: Statistics Canada
The agency, which said the analysis was done as part of its “Environmental Census” program, noted that urban vegetation helps “contribute to more livable communities and the overall quality of life for residents.”
But Dr Sandalak said that too often such benefits were not taken seriously.
“If something is going to be cut in the budget, that’s fine, we’re going to cut soft things like landscape, like trees — instead of really valuing them properly and saying they should be at the top of the pyramid,” she said. “I think climate change might be one of the motivators that makes cities think about this thing in a different way.”
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