I had the pleasure of participating on Jerry Agar's program on Newstalk 1010 in Toronto, with host Tasha Kheiriddin on August 15. The subject was a new report by the David Suzuki Foundation lauding the benefits of Toronto's greenbelt greenhouse gas (GHG) emission reduction role as a carbon sink.
Ms. Kheiriddin was interested in the other side of the issue, which I was happy to summarize. First and foremost, for all of their claimed benefits, greenbelts around growing cities have serious consequences. They force population densities up, which makes traffic more congested. This is because as densities rise, traffic volumes increase. There are various estimates of the increase in traffic congestion from a doubling of density, from (for example) 61 percent (Sierra Club) to 96 percent (Ewing and Cervero). The greater congestion produces more intense local air pollution, with the predictable health effects. Beyond that, as any Economics 101 student should know, rationing anything (such as land) tends to be associated with higher prices. It is no wonder that house prices have skyrocketed since the greenbelt was established.
It is important to understand the dynamics of GHGs. It doesn't matter whether they occur in the Toronto greenbelt or Patagonia. This means that there is no reason for GHG reduction to emanate from the Toronto greenbelt. It would be far better to forest some of the 7.5 million acres of disused farmland in Ontario (since 1951). This is many times as much land as the Toronto greenbelt. In other words, from a global (or local GHG emission perspective), the Toronto greenbelt is irrelevant (Note).
The purpose of the city (metropolitan area) should be to facilitate higher discretionary incomes for its residents, while minimizing poverty, all within the constraints of sufficient environmental protection. The greenbelt reduces discretionary incomes by restricting mobility (more traffic congestion) and raising house prices. It increases poverty by raising costs and preventing job creation. The greenbelt's claimed GHG emission benefits can readily be replaced by strategies elsewhere that do not reduce economic growth.
Note: Large portions of the farmland in Ontario and Quebec have been taken out of production since 1951, as production has been transferred to the Prairie provinces (Alberta, Saskatchewan and Manitoba). Meanwhile, the real value of agricultural production in Canada increased 160 percent from 1961 to 2005.