Design must account for climate change

Opinion

Hey there, time traveller!
This article was published 11/07/2021 (1166 days ago), so information in it may no longer be current.

I don’t often write about personal experiences, but the last few weeks have been impactful. We all learned the new phrase “heat dome” and watched temperatures in the western half of the continent skyrocket to historic levels. The unrelenting heat is believed to have killed as many as 500 people in the province of British Columbia alone, along with millions of marine animals along Canada’s Pacific coast.

The small village of Lytton, B.C., recorded the highest temperature ever seen in Canada on three consecutive days, and on the fourth day, it was destroyed by wildfire.

As this climate-change-driven disaster unfolded across the West, I spent the week helping a client apply for a federal government green building grant through Infrastructure Canada. Called the Green and Inclusive Community Buildings Program, it asked for many of the typical requirements — energy-use reductions, lowered greenhouse-gas emissions targets — but the last half of the application focused on how the project will be resilient, how it will survive, in the face of the climate reality.

No longer is sustainability solely about carbon reduction to prevent or mitigate climate change; it is now also focused on adapting to what is already here and what is unavoidably coming toward us. It was a powerful realization.

To design buildings and cities that are resilient to climate change, it is important to understand what is happening. According to the Prairie Climate Centre, by 2080 average temperatures in Winnipeg are projected to increase by 6.9 C, with the average number of high-heat days (above 30 C) rising from 14 to 52 per year. Winters will be warmer, with an increase in precipitation of up to 25 per cent.

While these shifts in average conditions are significant, the more profound effects of climate change on cities will be the increase in extreme weather events such as longer heat waves, drought and more frequent heavy rain, ice and hailstorms. Winters will see an increase in polar vortex outbreaks causing extreme cold snaps.

Building design that responds to these impacts will be fundamental in creating climate-resilient cities. Structural systems will be required to anticipate ground movement during drought conditions and periodic soil saturation from deluge rains. Many homeowners are already seeing the impacts of this on their shifting basement foundations. Greater winter temperature fluctuations will bring an increased number of freeze/thaw cycles, further stressing building components.

Higher temperatures and corresponding air-conditioning use will increase electrical demand, which may stress provincial power grids. During last week’s heat dome event, Alberta and Saskatchewan struggled to meet power demands, with the Alberta Electric System Operator declaring an energy emergency. Resilient buildings will mitigate this risk by incorporating passive cooling methods such as natural shading and ventilation, high levels of insulation, thermally reflective materials for roof and building facades, and on-site generation of renewable energy.

Green roofs on buildings can also reduce energy use for cooling, as well as retain rainwater and reduce runoff, moderate temperatures and improve air quality. In 2009, the city of Toronto passed a green roof bylaw, requiring green roofs on new developments. As of 2019, approximately 620 new green roofs, covering 501,000 square metres, had been constructed, lowering the citywide temperature by an estimated 1.5 C, and by 4 C in high-density areas such as downtown.

In 2017, before she was famous, Dr. Theresa Tam, Canada’s chief public health officer, authored a report indicating that addressing higher urban temperatures through interventions such as trees and green space can reduce the factors that contribute to chronic disease, heat-related illness and deaths. A 2016 Toronto study found that in extreme heat conditions, a 2 C to 3 C increase in air temperatures can translate to a four to seven per cent increase in the mortality rate attributable to heat. These factors are particularly important for marginalized and lower-income groups living in less climate-resilient housing and neighbourhoods.

Trees and vegetation can also help cities control the increased effects of wind, stormwater runoff and overland flooding to reduce stress on sewer systems. Trees in Winnipeg currently prevent one million cubic metres of stormwater, or 500 Olympic-sized swimming pools of water, from entering the storm system each year.

Mitigating the tide of climate change that is already rising around us is a global effort that requires renewed commitment and action, but cities will be on the front lines. Building local resiliency that will help community institutions, neighbourhoods, businesses and individuals survive and adapt in the face of climate change.

Emergency planning for floods, storms, drought, water shortages, power outages and refuge during extreme temperature conditions will also become increasingly important. Without strong planning initiatives and implemented climate-change strategies that not only focus on carbon reduction, but also on forward-looking climate-change resiliency, cities will experience major impacts on local economies, deterioration in health and quality of life, and severely deepening social and economic divides.

Brent Bellamy is senior design architect for Number Ten Architectural Group.