Extreme heat in Canada should be fought with grey, green infrastructure, says UWaterloo report


A new report from the University of Waterloo is recommending a combination of grey and green infrastructure to combat the increasing frequency of extreme heat in Canada, which will only continue to soar to new levels.

The university’s Intact Centre on Climate Adaptation report notes that Canada has warmed at twice the global rate between 1948 and 2016, with annual mean temperatures increasing by 1.7°C. Much of Canada will experience extreme temperatures in the years 2051–2080, according to projections.

The report zeroes in on towns and cities, where urban heat islands can present some of the more daunting challenges. In these areas, daytime surface temperatures can be as much as 10-15°C higher than more remote regions.

“The risks of extreme heat are commonly considered in terms of health impacts, with the media focusing largely on heat-related deaths. However, extreme heat also has adverse effects on infrastructure and services, natural systems and ultimately, the economy, as exemplified by the range of impacts identified by the City of Montreal,” states the report, referencing the city’s Climate Change Adaptation Plan.

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The Montreal plan is filled with warnings about extreme heat’s effects on road surfaces, as well as the increased demand on municipal services such as  drinking water. Heat can create shorter system idle time that can weaken water systems in case of problems, the plan notes. Additionally, heat can mean an increased presence of cyanobacteria in the water, requiring ozone treatment, as well as faster degradation of chlorine in the system, which will increase re-chlorination needs and associated operating costs.

“Extreme temperatures may increase community demand for water and wastewater treatment services at times when water levels are low,” states the University of Waterloo report.

Working with nature as green infrastructure, as well as improving buildings and public infrastructure as grey infrastructure, can help combat extreme heat, the report says. Green infrastructure can mean planting and maintaining trees in grounds and parking areas, expanding vegetated areas that can absorb water around buildings, or installing green walls.

Grey infrastructure improvements can consist of measures such as installing and maintaining backup power generation, or arranging for backup water supply during power outages. Additionally, buildings can enhance insulation and airtightness, use concrete, brick, stone and tile finishes that absorb heat, or install windows that reduce heat gain from the sun.

The report states that once a community has assessed infrastructure for vulnerabilities to extreme heat, it can work to reduce the risks to the infrastructure itself.

“When communities are designing new infrastructure or adapting existing infrastructure to be heat-resilient, they should consider future potential climatic conditions, including the risks from extreme heat, as a matter of routine,” the report suggests.


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