If Toronto is anything like Vancouver, then it is a very low density city, unlike all the large European cities. Therefore there is lots of room to build by increasing density, without any need to encroach on greenbelt or farmland. The only reason to build on farmland is because it is cheap and easy. Of course there is a price to pay later in infrastructure and transportation costs, but the developers do not pay that price. It is criminal to use farmland for housing, it is not an easily renewable resource, and it is essential for our long-term survival.