There's way too much depth in this (wonderful, cautiously hopeful) series to pack into a movie, or even a trilogy.

Good.

Now let's start preparing for the next one.

Virtually everybody I knew in the US Peace Corps had read and been inspired by Mountains Beyond Mountains. It's safe to say it'd been a strong nudge in that direction for many.

We are green on opsec!

Now let's add an externally-controlled backdoor to everything else, too, and that'll work out great.

Also, everyone within the US already should exercise increased caution.

I mean, they also bought the F-35.

In all fairness, the F-35 does what it says on the tin. Azure doesn't. That you bring this up says a lot more about you than government purchasing.

It does _now_, since the deliverable capabilities and pricing changed well after the ink on the contracts was dry. The F35 program was picked over by experts and denounced internally, but went forward as a purchase anyway.

Certainly that's not how the Europeans started out interacting with north America's natural resource. Mostly they treated it like the US does oil deposits now. https://en.wikipedia.org/wiki/Broad_Arrow_Policy

We do in terms of acreage. A lot of that is reclaimed farmland. Old-growth hardwoods are still down overall, and will remain so; that can take multiple hundreds of years to recover, since cleared forests regrow in phases.

Right. And tree coverage is not the be-all-end-all. My family visited the plantation where a few of our ancestors were enslaved; it had been turned into a state-run forest preserve (partly as a bid for the prior owners to hide the extent of the operation). Unfortunately, the farming practices employed back then have scarred the land; near where one of the slave cabins had stood, we were shown a large anthropogenic ravine that had been created by farming-related soil erosion. These places aren't quite the same forests as they were before European settling.

There's also the case of the near-loss of the American Chestnut.

Folks, "Limits to Growth" was published _over fifty years ago_ (https://www.clubofrome.org/ltg50/) and revisited repeatedly since, each time in so doing effectively confirming their worst-case hypotheses.

Yes, their website is...unconvincing. Which is poetic in its own way. Wikipedia's take on the original report at https://en.wikipedia.org/wiki/The_Limits_to_Growth is probably a better read.

But we've been able to take a highly systems thinking-inflected, as quantitative as possible approach to looking over how human's current perspective of what "growth" means and applying it over time to the resources of the planet we live on, and conclude with decent confidence and error bars that it's not just unsustainable, but that we're past the point of overconsumption and will have a very uncomfortable "correction", and we've been able to indicate that for decades.

Back when LtG came out, there was a study of the limits imposed by resource availability. The conclusion was that, to first approximation, the only resource that we had to worry about was energy. Fossil fuels would have to go, but everything else was either available in effectively unlimited amounts or could be substituted with things that were. An example of the latter was mercury -- effectively all previous uses have been replaced with better substitutes (because of toxicity issues, not shortage of the element.)

Pollution also has to be worried about, but there's nothing in a non-fossil fuel powered world that would prevent the current world population from enjoying prosperity indefinitely. There are ultimate limits to energy use on Earth from direct thermal pollution but the world could enjoy US levels of wealth without great trouble.

The exponential process one should be most concerned about today is exponential decline in population.

When is the world population expected to decline? Or are you talking about a specific country?

Before the end of the century: https://en.wikipedia.org/wiki/Human_population_projections

I'm talking about the entire world.

Almost everywhere, the total fertility rate is well below replacement (which is around 2.1). UN estimates that say global population will peak around 2084; they assume global TFR increases back to 1.6, but there is no evidence for this assumption, so global population will likely peak sooner. Every first world country will be in population decline by 2050; some already are.

There's something about global civilization that's acting like a kind of human pesticide. People just aren't having kids, and this is getting worse, not better.

So it seems there is a median projection of mild decline way in the future. There are also reasonably probable scenarios that show no decline, or more precipitous decline. However, they generally agree that there will be at least 1 billion more people in the world, most likely 2 billion, and possibly more.

What is the real risk of the Earth eventually going back toward having 8 billion people after reaching 10 billion? Why is this "the exponential process one should be most concerned about today"?

The real risk is the TFR never rises and population drops until complex society cannot be maintained. Or perhaps some weird minority with higher TFR takes over the world, what I call the "Amish Scenario".

Are you talking mainly about demographics? Like not enough working age people and too many older people?

Yes, and also that if the population becomes small enough it becomes impossible to sustain an industrial society due to lack of scale.

Isn't most of industrial society really just trying to deal with the problems of having to sustain so many people?

about 50-60 years iirc

Looking at this somewhat critically, did the predictions not turn out to be completely incorrect?

Specifically the industrial output and food per person, as well as the "available ressources" curve.

In my view, this should have been expected from the very start. Every single fixed-reserve + extrapolated usage rate calculation that we ever did produced incorrect predictions from what I know (and I'm not even really exaggerating here); this happens because increasing scarcity provides a lot of backpressure against both assumptions.

Just consider e.g. fracking or oil sands for the "fixed reserves" of something like gas (from a 1970 perspective), and things like aluminium conductors for the "extrapolated use rate" for something like copper.

I'm not saying that the whole concept is wrong. Long term exponential growth is obviously going to run into a wall basically by definition.

But I think for humanity right now, current population trends (i.e. negative growth everywhere) is all we need to keep ressource usage physically possible for the next centuries at least (and probably going to cause negative economic growth simply from population decrease).