The study by University of Toronto Civil Engineering Professor Chris Kennedy and World Bank climate change specialist Lorraine Sugar, showed that it is technically possible for cities to reduce their greenhouse gas emissions by 70 per cent or more in the long-term.
Kennedy and Sugar made the claim in 'A low carbon infrastructure plan for Toronto, Canada,' published in the latest issue of The Canadian Journal of Civil Engineering.
They noted that over half of the world's population lives in urban areas and over 70 per cent of global greenhouse gas emissions can be attributed to cities.
"It is possible for a Canadian city, in this case Toronto, to reduce its GHG emissions by the sort of magnitudes that the international scientific community have indicated are necessary globally to keep global temperature rise below 2 C," Kennedy and Sugar wrote.
"With current policies, especially cleaning of the electricity grid, Toronto's per-capita GHG emissions could be reduced by 30 per cent over the next 20 years," they said.
"To go further, however, reducing emissions in the order of 70 per cent, would require significant retrofitting of the building stock, utilization of renewable heating and cooling systems, and the complete proliferation of electric, or other low carbon, automobiles," they added.
According to Kennedy, the biggest obstacle is the city's building stock, as they have a lifespan measured in decades, so it takes time to replace older buildings with more energy-efficient ones.