I've been thinking about something last night. I'm starting to think that this could be it, that what we're experiencing right now is the height of human civilization on Earth.
I think that, because we didn't build up nuclear energy in time, we will fail to make the transition away from fossil fuels fast enough, we'll run out, and we'll reach a point where we won't be able to make enough energy to sustain societies as they are today.
A collapse will come. But that's not the real issue. The real issue is that without an abundance of oil anymore, without that much cheap energy, human civilization won't be able to rebound, and will basically remain stuck to somewhere around steam engine stage. At best we might see steampunk become a reality.

I've been thinking about something similar for some time. Humanity owes its technological advancement to fossil fuels. To forests and critters of countless millions of years ago that died and got buried before they could decompose.
As such, ANY intelligent alien civilization NEEDS to evolve on a planet that has fossil fuels in the ground already. If an intelligent life form evolves before fossil fuels get created through geological processes, or where they don't exist for any other reason, that's it. That's a technological dead end for them. They'll be stuck at a medieval stage, forever.

"But muh solar power" NO! You're not gonna make solar panels from burning wood. If you're struggling to barely melt metal, you're not gonna have the cheap resources needed to experiment and research anything more than a basic axe and a sword.
And remember the social panic there was in the 90s, that we were cutting down all trees to make paper? Now imagine trying to sustain a high population civilization that BURNS only wood for everything.
You are not building a technological civilization off of wood. At the very minimum you need coal, but realistically you need oil. No civilization, alien or otherwise, will EVER make the transition from burning wood to solar panels. Same goes for wind. You think you'll create fine copper wire to make electric engines and generators by burning wood?

Now going back to humanity. If societies collapse. That's it. We don't have readily available oil. The reserves we still have need highly advanced machinery to extract. Machinery that might not survive a collapse, or that we'll lose the knowledge of how to use.
We still have a lot of coal, but I'm not sure if even that is easily exploitable anymore. Can you still find coal with nothing more than pickaxes as tools?
After the collapse happens, there will be no more smartphones, no more computers, no more internet, anymore. Ever. For as long as Earth continues to orbit around the Sun, humanity will continue, but will remain stuck in much more primitive societies.

This is not something I expect to happen in the next decade. Not in our lifetimes either. Could take a few centuries. But I think it could happen.
Our energy needs are growing too fast. First cryptocoin and now AI have been the world's dumbest ideas when we're struggling to deal with finding energy alternatives. And dumber ideas are sure to be on the horizon still.
IF nuclear energy had been abundant, this wouldn't have been an issue. But instead of growing nuclear capabilities, we've decimated them. Now there's talks about a revitalization. But projections for the first batches of new generation nuclear power plants are for like 2050 or something. And that's assuming the political willpower is maintained until then. Which... fucking hell people... western nations can't keep it together for 5 years, let alone decades.
Even if I assume mere stupidity, and not outright malice, the world's political system is essentially trying to kill humanity.

But going back a bit, with energy usage growing so fast, at some point something will collapse. If people start rioting and pillaging AI server farms and solar plants, if people start chaos and revolutions, you think energy plants will survive? You think fragile solar panels will be intact? You'll have South Africa style situations where the infrastructure will be compromised, and left in taters to the point where you can't even use every bit of energy making capacity you have left to create new solar panels, new windfarms, etc.
You won't be able to grow back, because trying to ration energy for basic industry instead of population needs will just get you a free noose around your neck as part of a new population revolt.
And solar panels wear out. So do wind farms. You won't be able to replace them, more and more of them will fail, until you have nothing left and are back to burning wood to stay warm during winter.

If you had an abundance of cheap oil, gas, coal, sure you can build back. Just burn more and more. But you're not building back from solar and wind.

I don't think it will happen within our lifetimes. So unless you care that much about your great-grandchildren, this really isn't something that will affect you. Not something you should care about.

But if you have some deep optimism and hope that one day humanity will reach the stars, if you're like me and hope humanity will exist forever more, discover everything there is to discover, explore all the deep blue and the cosmos, reach the pinnacle of science and technology that we can't even imagine yet... If you're romantic in that way... this is a sobering thought to consider.

@alyx
> I don't think it will happen within our lifetimes.

I'm getting kinda tired of saying this, but living forever is a possibility within our lifetimes. If the first life extension treatment is released within your lifetime, you have more time to receive the second life extension treatment. This can keep happening until immortality is possible.

Also, if trends continue, a $1000 PC will be strong enough to run a human mind on by 2080, meaning that the average Joe could potentially upload their mind by then and live forever.

@Nepiant
>Also, if trends continue
The trend won't continue. Silicon chips are already getting to the level where electrons can quantum tunnel out of the transistors. I think soon we'll count the width of transistors by the number of atoms in them. Silicon is coming close to physical limits.
And quantum computers are shit. They can't even really offer what they were promised to do, that is being able to performs computations that binary computers are unable to. Turns out, any algorithm you'd want to do on a quantum computer can be calculated on a traditional binary supercomputer computer too.

I'm sure medical treatments that can improve lifetimes will come. I've seen that there's been massive progress with diabetes for example. But immortality? Nah... I don't see uploading the human mind as something being feasible even within an extended lifetime.

Moore's law is basically dead. Even NVidia is saying it these days. Why do you think they're pushing for AI generation crap in video games (fake frames and AI upscaling)? Because they already know they can't cram that many transistors in the same space anymore.