In recent years Canada has experienced absurdly rapid growth in total population by any standard. It doesn't matter that much of it is from immigration, that's beside the point. Even without any immigrants the population would've been growing still. It's already grown to levels that stretch our natural resources per capita much thinner than they used to be. I remember even in my youth, in the 1980s, my father pointing at the vast new suburbs surrounding his hometown and lamenting how much of the best farmland had already been paved over. Growth like this cannot continue, it's got to stop at some point. Slowing it down a little would be nice, if we have that power. It wouldn't magically fix all our problems with housing and everything else, but it sure wouldn't hurt. It would at least buy us time to learn how to do development in less environmentally destructive ways.
On the other hand, borders suck and I'd prefer to live in a world without any. It's a dilemma keenly felt and little understood even in Canada where it's endlessly discussed.
The issue isn't growth. The issue is that we're deliberately choosing to grow in inefficient ways.
We wouldn't have ever had to pave over any of that greenspace if we simply gave up single family homes and build decent apartments and condos in their place. Especially if they're mixed use so businesses can occupy the first floor. An entire hectare of farmland converted to housing could be saved by a single low-rise apartment that takes up the space of a single city block. Make that a high-rise and you saved a dozen hacares. That's an entire farm, and not a minor family one, but a decent corporate one.
In addition, you're saving on electricity, water, and tons of other resources by not having to build infrastructure that goes out kilometers on end, and instead just extend it a dozen meters for a single large building. Heating and cooling gets easier and cheaper as it's far more efficient to heat/cool one building than it is to do the same to hundreds that are all separated and spewing hot air at each other.
Most of the modern problems are caused by choosing to be wasteful. We waste half of our produce because it's not pretty enough to be sold in grocery shelves. 80% of crops goes to feeding livestock. We bulldoze entire neighbourhoods just so we can make a six lane highway go through the middle of a city. Amazon owns a private garbage pit it just throws stuff into because they make more shit than they sell. And I'm talking about tens of millions of dollars worth of products a year.
We're insanely wasteful, and that's the real reason why things are so shit. It's not because there's too many people. It's because those in power would rather keep the status quo than actually make a positive difference. And any change they do make always has to be the quick and easy one, not something that actually fixes the problem.
A radical redesign of our urban landscape along the lines of what you suggest would be a good start, but even that is not going to happen quickly or any time soon in most of the country. There are any number of things we could do, any number of things we definitely should do, and many of the ones you list are certainly among them even if they are not in themselves sufficient. But it's not happening, not just now. Canada remains stubbornly set on an unsustainable path. We are oil dependent to a horrifying degree. Without petroleum exports our balance of trade would be a disaster. It's looking quite bad even while the country still is a major oil exporter. Agriculture is about to take a hit from climate change. Things will continue getting worse before they get better even if our politicians do suddenly come to their senses and start getting serious about redesigning the way our cities and economy function.
Meanwhile we will continue to have the worst of both worlds: Rapid population growth driven by net migration, as well as tightly-controlled borders to keep out the officially undesirable people.
We're actually not that bad when it comes to fossil fuels. Yes, petroleum exports are pretty bad (14% of all exports by value), but from an energy generation standpoint, oil only comes in after both wind and nuclear. Most of our electricity actually comes from hydro, despite the prairies having zero waterfalls. Our carbon emissions are actually mostly coming from home heating, which is pretty bad admittedly, but we're finally starting to do something about it by subsidizing heat pumps, at least on the east coast.
As for the housing bit, yea. For-profit organizations are always going to do whatever is the combination of easiest and most profitable. Things won't change unless if you make things either horribly unprofitable, or the government steps in and does it themselves. And of the two, I think the latter is the only way to make worthwhile change quickly. The government can quickly change the laws and nullify things like housing associations so that proper mixed use housing can be legalized in most places, then actually contract companies to make them, and make them quickly. It only takes two years to turn a plot of land into a fully functional mid-rise building, and that's taking into consideration Toronto's bad soil qualities for construction. One year for places with stable soil.
And if the government owns the buildings, it easily has the resources to actually have these buildings built, and could start raking in the profits as they'll be filled out with pre-purchases immediately.
We’re actually not that bad when it comes to fossil fuels.
Where did you get that idea? Not that it's the only problem, but fossil fuel use in Canada is currently bouncing back towards its pre-pandemic all-time highs.
I was talking about how our electricity generation isn't that bad: https://www.statista.com/statistics/248155/electricity-generation-in-canada-by-type/
Admittedly I was wrong about how high wind was, but for this one metric, the numbers aren't that bad. The issue is that most of the fossil fuel is used in heating, which is different from electricity generation, and is difficult to deal with because it's completely decentralized. On the other hand, it's not nearly as bad as other places, as proper subsidies on heat pumps nation wide.
Canada is definitely at the top of energy usage per capita, but that's not a problem as long as that energy source is from somewhere that isn't polluting. We're not there yet, but the solution isn't difficult. Hell, there isn't even any sort of public pushback against the sort of change that is needed, unlike in Germany or something.