Present necessity

So, Canadian, so we start with "peace, order, and good government".

This is a problem, because a whole lot of people have widely divergent ideas about how to define those things.  ("A settler can shoot indigenous persons if upset with them" is still a legally-protected position in Canada, for example.)

There's also the problem that "permanent emergency" is usually thought of as a political device rather than a material condition. We're moving into circumstances in which it is our material condition.  (Temperature peaks several centuries from now.  Everything gets worse until after the temperature peak somewhere.)

So, problem zero; retain enough technological civilization to keep feeding ourselves AND get through the peak temperature period.  (Just like you have to eat every day, you can't go above 35 C wet-bulb for very long and live; the solution to these problems has to be continuous.)

As these things go, we haven't got much longer with stable agriculture; if we lose that, we're done.   You can't maintain civilization during a famine.  (Innumerable historical examples!)

But we also can't do anything effective towards the "local post-carbon toolkit" and "post-agricultural food supply" problems because most of the population is intensely committed to the status quo.

What does it take to get off the status quo?

1. prosperity; 
• in the time of angry weather, the existing housing stock is worthless.  The remnant middle class is defined by home ownership, and they vote.  Anything that acknowledges the worthlessness of the extant housing stock or the impracticality of the post-war suburban distribution pattern is a political non-starter.  So any political solution must involve a massive public home replacement program at guaranteed values.
• wages are too low because of rent extraction and wealth concentration; the wealth concentration is a major source of political opposition to any change to the status quo of the role of society being to guarantee concentrations of wealth.  The way in which the infrastructure changeover is organized has to produce immediate, obvious increases in the material prosperity of pretty much everybody
• you can use less energy if you're more efficient, but you can't generally get people to accept a lower standard of living.  Hot showers, good communications, soft beds, and a varied diet are absolute requirements of any intended social reorganization because everyone knows this isn't temporary.  This is the new pattern for civilization up to and past the temperature peak.
• really large fractions of the population do not care about the future more than they care about not feeling that they have lost status right now.  A major sales effort will be required.
2. accounting
• capitalism works by keeping costs of the books to increase what can be considered profit.  (If you have to pay people what they want for their homes, that mine won't make money (or happen at all), et  multi cetera.)  It turns out this is how you get most of our current problems. 
• You can keep a market economy but you have to do the accounting accurately.  General-case emissions taxes would be a good start.  (All emissions, not just carbon.) Otherwise, the system is missing feedbacks and inevitably becomes destructive.
• the human trick is ganging up on problems; we're darn near eusocial.  Current capitalist orthodoxy insists on individuals or corporations.  We're going to need more, and flexibly arrived at, patterns of collective organization.  Which means we're going to have to forbid the "protect wealth concentration" version, which is the social equivalent of a destructive invasive like phragmites or kudzu.
• some model for ecological services that prices them accurately (that is, these things are expensive; killing soil by paving it should ALSO be expensive)
3. technology
• we've got (nigh) all the pieces
• major challenges are all "do something that will really displace an incumbent" political problems, rather than technical possibility.
• we need something that doesn't depend on long supply chains or just-in-time fulfillment or presume an integrated trans-national economy of several billion. Those aren't bad things, but they're not resilient things.  We need to replace the Industrial Revolution coal, iron, and brass toolkit with something a couple million people can keep going over a (relatively) small geographical area, and build up from there.  Trade is good but all the ports are going to drown; we mustn't plan on steady, high-volume trade.
4. food
• decarbonized agriculture; no fossil carbon anything, whether fuel, fertilizer, or pesticides.
• post-agricultural food supply; this necessarily means management practices that increase diversity and disparity of the organisms because we're going to be compelled to optimize robustness in the food supply, rather than productivity per person (which is what mechanized agriculture optimizes).
• diversity; the massive reliance on wheat, maize, and rice is going to end.  We're going to be eating a lot of weird stuff and need to work at getting as much of it into the future as we can.
• bioaccumulating anything-that-isn't-food is a problem; plastics, pseudo-hormonal compounds, persistent toxins in pesticides, anything like that. Keeping a reliable food supply means not doing that.  (An organism turns food into shit; an ecology turns shit into food.  If the ecology can't turn it into food, you can't emit it.)