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Scientists at the University of Alberta in research announced last month found stark differences in surface temperatures between local urban and rural areas because of human-caused global warming and a loss of vegetation. Urban hotspots will become more of a problem as global temperatures rise and heat waves — which can have catastrophic consequences — become more common in the future. Just last year, 66 more people died in Alberta than usual after an intense heat wave.
Ground temperatures in numerous areas within Edmonton jumped by between 6 C and 12 C compared to rural areas in the last 20 years, researchers found. Places that are more “built up” with roads, buildings, sidewalks and parking lots, have more concrete and asphalt. Those materials absorb heat, release it slowly, and keep temperatures high.
Areas around the river valley were cooler than others — areas occupied by wealthier Edmontonians. Neighbourhoods where Edmonotonians with lower socio-economic status live, and lone-parent households, were hotter.
Scientist and co-author Sandeep Agrawal told the Canadian Press the city’s urban planning teams need to take hot temperatures into account, not just cold weather, and find ways of preserving trees and other greenery to mitigate the impacts.
Ward Métis Coun. Ashley Salvador agrees.
“I think there’s a really clear connection between urban planning and design of our neighbourhoods, equity and the urban heat island effect,” she told Postmedia in a recent interview. “There’s also variability based on the age of a neighbourhood. A lot of communities that have big, mature trees, you can really feel the difference when you travel between (them).”
Edmonton already has a goal to plant two million new trees.
Salvador said urban heat islands will be part of the discussion for this work. As the city continues with neighbourhood renewal, there’s an opportunity to look at both preserving existing trees on public and private property, and building more trees and vegetation into neighbourhood design, she said.
“When we talk about planting new trees you can look at it from so many angles, not just sustainability and climate resilience, and heat island effect, but also livability,” she said.
“The urban heat island effect, yes, it’s about city property and public trees, but it’s also about the private trees that contribute to that urban tree canopy as well.”
Salvador is an urban planner by trade. She notes that many of Edmonton’s mature neighbourhoods have more boulevard trees because this was part of the city’s design philosophy going back in the ’50s and ’60s — a stark contrast to some newer areas.
“Neighborhoods were not intentionally built with three boulevards, the streets themselves are actually a lot wider, more in that sort of curvilinear suburban style,” she said. “I think we’re at the point now where we’re realizing how much value trees add to our livability, our climate resilience. We’re trying to get back to that.”
Adding new and protecting existing trees is also part of City Plan, a master document meant to guide all aspects of the city’s work. Salvador said this sets a high bar for policies like construction standards and street design guidelines, and making sure they are aligned to help the city achieve that larger vision.
“That’s what we’re doing now, I would say. We’re in the phase where we’re trying to implement the vision of City Plan into these conversations.”
City prepares for climate change in Edmonton
The U of A’s research was partially funded by the City of Edmonton.
As Edmonton’s climate warms, the city’s urban strategist Lindsey Butterfield said understanding the why, where, and what of these conditions becomes more urgent, as well as solutions.
“This research is going to be really valuable for us and then making those adaptive choices,” she told Postmedia this week.
While the city doesn’t currently have plans to specifically address heat islands, Butterfield said there’s a number of initiatives underway that will make an impact.
Open option parking is one. This policy removed on-site parking requirements in the zoning bylaw, meaning fewer large parking lots may be built. More requirements for landscape may also be put into zoning rules as the city works on overhauling the bylaw, she said.
Design and construction standards, planning around the urban tree canopy and modernizing the river valley are three others.
“Adaptation isn’t just one thing. It is really about everything in the city contributing to mitigate those climate change impacts,” Butterfield said.
Buttefield said the heat island research is new and the city is still working on unpacking its findings and how to move forward, but it is making her reflect.
“How do we build a rebuildable city? How do we redevelop the parts of the city that aren’t serving our residents as well as they need to?” she said. “It just gives us that data point to look at what do we need to do differently.”
An update on the city’s work around the urban tree canopy is set to return to a council committee early next year.
A public map of the heat islands along with wildfire risks should be released next year, says Chandra Tomaras, the city’s director of environment and climate resilience.
Source: EdmontonJournal
