I believe that the collapse of our global civilization is both inevitable and imminent. Climate changes make it inevitable. Peak oil and cultural bankruptcy make it imminent.
Collapsniks are often portrayed as alarmists by people who point out that our civilization can easily absorb short term effects of climate changes and that the real tricky effects of it will only show themselves in 50 years.
Scientifically, I tend to think that this argument can stand, although our good old phronesis and the slew of "faster than expected" types of event lately erodes its rhetorical power. However, I'm not interested in arguing on that level. Let's give it to them: civilization's collapse due to climate changes isn't imminent, and is only likely to happen in 50 years or more in the "business as usual" scenario.
What I'm more interested in is that regardless of its timeline, we're going to get there, we're going to reach the threshold where civilization collapses. So, you can make the point that civilization still stands at 3C. When does it fall? 4C? 6C? 8C? We're going to reach it because we've already failed. 1.5C was the limit, we busted it. The goalpost has moved to 2C, but we're going to bust it too. The feedback loops have begun and are out of our control now.
So what if "business as usual" only takes us to 4C in 2100. What do you think happens next? Nothing? Good job Johnny, we've made it? No, the feedback loops continue to make our lives increasingly miserable, continue to divert our energy from de-carbonisation and into dikes, masks, water desalinators, mechanical replacements to bees, replacing infrastructure degrading prematurely, power generators to cope with increasing grid failures.
"Defeatist!", you might spit at me. Sure, let's give our 120% and do our part. If we dismiss, for an instant, the sad truth that what "doing our part" is often isn't what we think it is (for example, the fact that lithium mines are an environmental disaster) and assume that we all swim in the the same direction, let's say we can get to 3C in 2100. Good job Johnny? Nope, still inevitable. Unlike what techno-optimists believe, it's not because you have the power to build a gun that you have the power to undo the effect of its bullets.
Our civilization is dying and our bankrupt culture prevents us from accepting this predicament, which moves us to my next point: collapse is in fact imminent.
It's official, we've passed peak oil in 2019. Big oil now officially admits it itself: even in their more optimist predictions, they are not expecting production to reach 2019's level again.
A lot of fun has been had, pointing at "peak oilers"' failed prediction: they couldn't foresee fracking. The same kind of fun has been made at malthusians because they couldn't foresee Haber-Bosch. Alright, fair enough, I hope you had a good time laughing.
However, when you look at it, the logic is still solid: There is a limited amount of oil reachable with a positive EROI and there is a limit to growth on a finite planet.
"Wait, wait, wait", you're telling me, "Big Oil is simply recognizing that renewables are the future". That's a fair point and it might very well be true, but please, allow me to try something else:
Big oil expects 2019 to be peak oil year because they know that all easy fracking spots are spent. The easy fracking is gone and can only survive through heavy subsidies.
The economic slowdown caused by the 2020 pandemic hurts these drillers big time. Because the pandemic is expected to affect oil demand for a long while, they're expected to go belly up. When energy demand grows again, their infrastructure will have rotten, further decreasing the EROI of low-tier fracking sites, so we won't ever open them up again.
This leaves us only with good old Easy Oil. Unless renewables have picked up in a major way before energy demand grows again, this can only mean a drastic increase in energy price. The price of energy will then be way above what the economy can support and this will precipitate another economic crisis.
But renewables will not pick up. There's too much mining to be done to even come close to fossil fuel's contribution to global energy demand and this involves too much oil, which will skyrocket in price. We're in the Energy Trap! A smart entity could have used the pandemic's oil crash to massively invest in renewables, but it doesn't seem like it happened. We're just really not that smart.
Then, what will happen is a bit like when an engine chokes: too much, not enough, too much, not enough, poof! Imagine this with energy price.
The underlying cause of this is that for 200 years, we've been on an energy binge. We're at the end of it, we're looking for our next fix, but there isn't going to be one. We just need to drastically reduce our energy consumption.
However, we're not going to because we're culturally bankrupt. We are utterly unable to see limits to growth. Individualism is so far ingrained into our culture that even when we face the greatest of challenges, maximisation of well-being and game theory will prevail.
We're facing the forced and drastic simplification of our social structures. We might take comfort in the fact that we aren't the first and, if we can avoid extinction of the human race, we won't be the last.
Joseph Tainter says that he has no knowledge of a civilization that voluntarily simplifies itself. With our hyper-individualistic culture, how can we possibly hope to achieve what greater civilizations couldn't?
Unlike the climate changes challenge, the energy challenge is imminent: peak oil is now. However, it is important to note that the effects of climate changes and peak oil are cumulative: raging forest fires, "once in a century" yearly floods, bomb cyclones, these are all energy consuming and further exacerbate the energy trap.
On top of that, there's what I would call the "future devaluation" of climate changes that kicks in. Today, right now, a 20 years old saving for her retirement makes absolutely no sense. That person has 0% chances of ever seeing that money again. In more and more places, a 30 years mortgage doesn't make much sense because that house is likely to be in a disaster zone before the mortgage is paid.
As the future is further devaluated by further climate catastrophes, as the inevitability of collapse becomes clearer to more people, those long term promises will mean less and less to more and more people. And promises are the basis of our financial system. That will precipitate the collapse of that system which would otherwise have "run on fumes" (faith) a bit longer.
Let's make something clear before I'm called a nutjob over this: I'm not 100% certain that collapse is inevitable and imminent. My prognosis doesn't come from a scientific method. Therefore, it's a belief, not knowledge.
In its current state, science cannot prove that we are likely to collapse, but it cannot prove that we are unlikely to collapse either.
This leaves us in this bleak fuzziness with regards to our collective future. It has become fuzzy enough that we can no longer consider it reasonable to assume a future that is consistent with the actions of our daily life. Because science has no answer, we have to make do with what we have and try to guess what that future will look like.
What made me turn to the "yup, we're fucked" camp was "Comment tout peut s'effondrer" by Pablo Servigne, Éditions du Seuil, 2015. It's not perfect, but is a very good introductory book, well written, pleasing to read (except for the existential sinking feeling). For french-impaired fellows, the book has recently been translated to English. For the impatient, Servigne and others wrote an interesting article on the subject.
Also, please note that I don't consider it unreasonable to not believe that collapse is likely to happen by 2030, so please, don't feel attacked by my beliefs.
I was going to write something here, but decided against it. Whatever you do, you and your family will need luck, so you might as well train it: take chances.
 I speak as someone who's part of the american culture. There are, of course, other cultures around the world and some of them will certainly fare better. However, american culture has been globalized. The collapse of the global supply chain following the collapse of the american empire will certainly deeply affect all civilizations of the world. I'd be ready to admit that some of those civilizations might be able to keep their civilizational quality through this global challenge, but I don't know enough about them to be sure. I wish them luck.
 except for Eastern romans, which according to Tainter had a somewhat orderly downsizing, but it was still because they had their back against the wall. It wasn't out of free will.