Chris Kennedy, assistant professor of engineering at U of T, is studying how Toronto resembles a living organism. He is researching “urban metabolism,” which examines the cycles of nutrients, water, energy and materials in cities.
Kennedy says that this type of analysis is useful because it “brings down everything to scale so you can see where it’s all coming from.” For example, the Kyoto Protocol mandates that countries lower their carbon dioxide emissions by a certain percentage. With Kennedy’s method we can look at where the emissions are coming from and tackle the problems specifically.
Kennedy is analyzing the metabolism of the GTA: 108 kilometers wide and inhabited by close to five million people. He is looking at four main cycles: nutrients, water, energy, and materials.
The GTA consumed 4.8 million metric tonnes of food in 1999. About 930 metric tonnes of water go through GTA taps each year, and in turn 798 metric tonnes of waste water are produced. Toronto has average efficiency when it comes to water, and looks very good compared to American cities, which are by far the least efficient worldwide.
An effect of the urban “body” that everyone in Toronto notices is the “urban heat island.” All the systems in the centre of Toronto are densely packed together and all are using energy. This energy gets converted into heat through one way or another, making a hot downtown even hotter.
Toronto has to keep going further to get its building materials. In the 1930s we obtained the ingredients for concrete from Scarborough; by the 1970s we were going 100 km away from the city centre.
Residential solid waste has gone down significantly as a result of recycling, but commercial waste, approximately 80 per cent of all our city’s waste, does not release its statistics.
Toronto is near the top of the world in energy consumption, which means that emissions are very high as well. The GTA emits 14 tonnes of carbon dioxide per person per year, a result of our reliance on cars. Kennedy said this relationship is related to density: Hong Kong is very dense with lower emissions per capita; Houston is not so dense and has higher emissions.
Kennedy said that even if we could develop a hydrogen fuel cell, it would take 66 per cent more power coming from Ontario’s energy sources to power all the GTA’s cars without fossil fuels. The only source that could be stepped up like that is nuclear, he said.
To close his lecture he said “If there’s one underlying message it’s that transportation is the biggie.”
