Transforming Home Construction: Essential Strategies to Maintain Temperatures Below 2°C

To combat global warming and maintain temperatures below 2°C, cities must drastically reduce greenhouse gas emissions from construction and infrastructure by over 90% within the next 20 to 40 years. This necessitates significant shifts in building design, material choices, or both.

“Canada aims to triple its housing construction rates amidst widespread housing shortages in the U.S., Australia, and many other countries,” explains Shoshanna Saxe from the University of Toronto. “How can we simultaneously meet these housing demands while significantly curbing pollution?”

Despite challenges, Saxe is optimistic. “We are already constructing buildings that meet sustainability goals; we just need to scale up our efforts,” she asserts. “Our expertise and knowledge are long-established; we need to utilize them effectively.”

Globally, the construction sector generates 10-20% of greenhouse gas emissions, primarily from cement production. Thus, understanding current construction emissions is crucial for countries and cities to plan reductions aligned with international climate objectives.

However, Saxe’s research team discovered a surprising lack of studies estimating construction emissions at the city level in Toronto.

“We developed a method to estimate city-level construction emissions and forecast future emissions to adhere to climate limits,” says team member Keegan Rankin, also from the University of Toronto.

Rankin’s analysis covered 1,033 cities, integrating existing models used for assessing the environmental impact of construction. He utilized data on city population, construction investment, and employment from sources like ExioBase. “These datasets were readily available, but combining them innovatively was unprecedented,” Saxe notes.

The team concluded the rate at which each city must reduce construction emissions to meet global carbon budget limits for a 2°C increase. “Understanding these budgets is essential for effective planning,” says Saxe.

The findings indicated that focusing solely on single-family homes to address housing needs would exhaust these budgets; cities should prioritize developing more efficient apartment buildings.

Employing alternative materials like wood and recycled concrete can help lower emissions, but good design remains paramount, adds Saxe.

“It’s a common misconception that merely building with wood resolves emission issues,” she clarifies. “Wood also emits greenhouse gases, and overly optimistic assumptions about forests may only lead to minimal emissions reductions.”

“Thoughtful building design is vital to minimize wasted space and materials,” Saxe emphasizes.

Rankin asserts that cities are uniquely positioned to implement change. “Cities are actively pursuing climate action and hold significant sway over construction practices,” he remarks. “As we identified in Toronto, many cities lack the resources to make informed budgeting choices.”

“Achieving the Paris Agreement’s goals hinges on addressing construction sector emissions, irrespective of reductions in other emissions,” says Prajar Pradhan from the University of Groningen. “Viewing emissions from a city budget perspective is also pivotal.”

It’s crucial to design buildings for low emissions not only during construction but throughout their lifespan, states Susan Roaf from Heriot-Watt University in the UK. “We cannot populate our growing cities with inefficient, pollution-heavy ‘zombie buildings,'” she cautions. Natural ventilation solutions can be a key factor in sustainability.

To reduce construction emissions effectively, prioritization of projects is essential. Saxe points out, “Canada continues to invest heavily in oil and gas infrastructure. We could accommodate housing for 10 million people without increasing emissions simply by reallocating those resources.”