If all man-made things were wiped out, how long would it take to re-create modern civilization?

I put my money on physically large boy scouts

Interesting point of view; I would be really amazed if we could recover that quickly from nothing or if what took it's place looked anything like we had now. If priority #2 was taken seriously and there was enough social cohesion present, and the survivors numbered among them the scientists, chemists, engineers, etc needed to record knowledge for future generations to hopefully use, and the generations following who were preoccupied with trying to build a civil society more in line with say modern day Denmark than some feudal society ruled by warlords actually understood the importance of preserving the information, and so on ... a lot of if's.

My concern would be that the people I imagine would be most likely to survive the chaos and carnage would be the LEAST likely to be concerned with recording and transferring knowledge. Interesting to think about, impossible to say.

Agho wrote:

This is a poorly-constructed question, and everybody posting here is looking at it completely wrong. 20,000 years ago is pre-agriculture. Essential crops like wheat, rice, and corn hadn’t even been bred yet. Hunter-gather lifestyles couldn’t begin to support current population levels. Prehistoric forests and plains couldn’t even shelter a non-negligible portion of the population, let alone feed them. There would be no time to worry about solving math problems or building things, only eating.

Virtually everybody would be dead within weeks.

This sounds about right.

The human population of the world in the stone age was a few million so you'd expect something like 99.9% of people to die out in the first year and anyone remaining to be in a daily struggle for survival. Maintaining any kind of high level social order that can meaningfully preserve our current knowledge base under such circumstances is going to be difficult. You'll have a bunch of warring nomadic tribes until agriculture can be established and you don't have the foundation to spare people for other pursuits until it is.

Obese people would have an advantage of not starving immediately.

The third world would see the least amount of change from their daily routine now.

Distance runners would be able to hobby jog their way to safe remote areas... like the Rift Valley.

We need a readily available running water source for farming... Nile, Tigress and Euphrates.

Karl Hungus wrote:

celery wrote:

The infrastructure in Europe was largely decimated after WWII, it took them less than 10 years to rebuild it. This shows that the most important part of a nations wealth is its human capital. What sits between the ears is 90% of the game.

If we did have a worldwide "tech restart" (forget about this prime number nonsense) - you'd see the population decimated within 75 years, with the third world really being hit hard - presumably you'd lose the ability to modify/combat crop diseases along with genetically modify things, so you'd see a massive drop in crop yield and caloric intake would drop. And things like no antiobiotics and inability to treat waste water or do water filtration would suck and kill people.

75 YEARS?

If we removed all tech invented after 1850, 70-80% of the population would be dead within months.

If we removed all tech invented after 20,000 BC, 95+% of the population would be dead within weeks.

We would not re-create it. Why would you want us to?

My timeline is a best of the best case scenario for sure, and does assume everyone was preoccupied with rebuilding. It is possible though, if the initial generation had the foresight. Their documents of technology and information, combined and accumulated around the world, would describe unimaginable technology and make astounding (correct) predictions. Combine that with a mandate to rebuild and rebuilding could become a religion in itself. Sounds like a plot for a sci-fi movie.

But I think people are missing on the type of knowledge you would want to pass on. The simple foundational knowledge will have the greatest impact. If all we started with were written language and hs level mathematics it would be a massive jump start of 15,000 out of the last 20,000 years. Once society and technology got rolling we breezed through relatively quickly. The 2nd time around we would have a description of the types of technologies that are possible. Detailed instructions from an engineer on how to build it would be nice but not necessary. We figured it out before. The time consuming part will be building a society.

It would be a race to record all the stored knowledge before those holding it died off. The most important thing to re-invent would be paper or some other method of recording a lot of knowledge permanently. Could humans create enough paper to record a significant amount of knowledge during a time where 99% of humanity is starving? Very doubtful. Within a month the knowledge needed to create a modern computer would be gone, and it is ridiculously hard to build a modern computer. Could we record enough knowledge in one month to leave bread crumbs that would allow future generations to race forward on the path to progress? Maybe, if the right people scratched the right stuff into the walls of the right cave.

The survival of a single renaissance man through the first purge would speed things up immensely. There aren't many of us though. 8)

One thing that would really help is that even those humans left would have some basic knowledge about medicine, hygiene, elements, metals, basic scientific principles, etc. That would cut many thousands of years off the learning curve.

How do we know this didn't already happen? Maybe the next prime number found will lead to the great unveiling of all the lost knowledge we once possessed.

12,000 years. This is an interesting premise in that most post apocalypse scenarios allow for clothing, stored food, cars, bicycles, and modern weapons. I think it would progress something like this if it happened right now.

Day 3 - nearly 100% of the population of northern US and Europe freeze to death.

Week 3 - 90% of the world's population is dead, due to weather and lack of food.

Month 3 - disease, starvation, and polluted water cause more deaths... 99% of the world's population is dead.

Year 3 - Population decline levels off with less than one million survivors worldwide. Of these, the vast majority will be tribes that currently live only a little above stone age and those who are fortunate to live in tropical regions with abundant wildlife.

Generation 3 - The old modern civilization is mostly a myth handed down by word of mouth.

Naked and Afraid wrote:

Distance runners would be able to hobby jog their way to safe remote areas... like the Rift Valley.

Good luck running anywhere in 20 degree weather without clothes or shoes. Even if hypothermia doesn't kill you, what are you going to eat? There's nothing but snow on the ground.

If this experiment was done in June instead of February, it would speed things up by decades.

Also, make sure you get your smallpox vaccinations before the experiment starts. It'll be back with a vengeance.

Interesting question. There would be an initial wave of high mortality from exposure, assuming mid-winter in the northern hemisphere, and lack of clean water for many. And then famine and disease would do a number over the next several months an years. There would be no social order and way to organize and communicate beyond a relatively small radius of a given location. Probably 80-90% would die within a year or two. But initially, the most survivable places might just be the "s***hole" countries of the 3rd world. Those communities that survived would devolve into chiefdoms run by warlords. But within decades (in favorable areas) agrarian societies would emerge and flourish. There would probably be a billion people living in bronze age conditions within 20 or 30 years. And with organized society some could advance fairly quickly. I think wars would set back things periodically, but within a few hundred or even a hundred years there could be a dawn of a new age with 19th and early 20th century technology and from there things would progress rapidly.

I think you are correct in your thoughts on where the most survivable places might be, and certainly after a period of complete chaos and brutality emergent social groups would be run by warlord/strongman types. That said, I think your idea we would be living in bronze age conditions in 20 or 30 years may be very optimistic, and I also believe your estimate of a billion people is high. Care to elaborate on your thoughts a bit? Genuinely interested.

I think the mortality rate would be quite a lot higher; the vast majority of the people living on this planet today have no clue whatsoever how to survive longer than a few days without packaged food, prefabricated shelter, how to make their own clothes, etc. Next to zero survival skills for most people. I wouldn't underestimate the absolute chaos that would ensue, the desperation, panic, brutality. It's one thing to slowly evolve 'towards' more civilization; it seems like it would be quite another to have it ripped completely away. Even subsistence farmers in the most primitive parts of Laos for example, are at least using steel implements, etc. Remove EVERYTHING from the equation; no fish hooks, no steel plows, all of it. I really wonder how many would survive long enough to even be able to resume rudimentary farming. I would not bet on more than 3-5% surviving the first year, and I think that's generous.

As far as smelting, things of that nature, I imagine it would be dependent upon the 'lottery' of people who survived (anyone with REAL skills/experience) and the length of time it took to began forming some organized social groups which could survive on more than hunting and gathering. The longer the period of time, the closer I think we'd be to having to start from nearly scratch. I think the time to actually DEVELOP smelting for example, would be somewhat compressed (even I, with no experience know if I find a couple different types of metal I could dump them into a fire and something stronger will come out) but it took home sapiens a very long time to figure this out. I don't think given the timeline of having to get back to some sort of organized society before smelting (or other technologies) could be resumed that we would come anywhere near bronze age metallurgy at anything approaching an economy of scale; not 20 or 30 years in my opinion. Maybe I'm just too pessimistic!

Sure. I am myopic. As so many people. Life expectancy over one week: 0,00000%.

Andaman people would probably not notice the difference though.

sssss wrote:

Honestly the hardest part would be finding and assembling all the right people in one place before they died living in the wild. The computing power necessary to find million+ digit primes is not very extensive and the algorithms that find them would still be stored away in certain peoples minds. If you had the right people working together I bet it could be down within a few years. 20 at the most.

You need about a thousand incremental steps before you're ready to program said computer.

IF the people with the right knowledge were still alive, you'd need,

-Mining engineers to find the proper metals. How the hell you're going to dig them out of the ground is another story entirely.

-Metalurgists and machinists to construct the materials needed to begin to make the circuitry for said computer. Sorry, but you're not going to find copper wire just below the surface.

-Someone has to build a power source. Can't just go plug into the High Aswan dam

-Semiconductor engineers would be needed to design all of the hardware for said computer

In the meantime, you've got to feed, clothe, protect those people....none of which would be easy.

sssss wrote:

Bad Wigins wrote:

How do you expect to even write down a million-digit prime number without rebuilding civilization to nearly its present state first? By which point, all the original victims of your evil wizard will have died naturally, and their descendants would only be wrecking themselves and everything they created if they revived the legendary world of their ancestors.

Large numbers aren't written down digit by digit lol. 2^77,232,917 − 1 is the current largest

Prove that another Mersenne prime exists.

250 years.

100 years to get to the 17th century or so. The ancient Egyptians, Romans, Maya, Inca, Chinese, and Greeks were all able to successfully create pre-Industrial Revolution civilization despite limited contact with each other, so the emergence of such civilizations are pretty much a given.

100 years to get from the 17th century to 1900. We know where all the fossil fuel deposits are, we know what they can be used for, and we will have at least partial information about manufacturing.

50 years to get from 1900 to the prime number. We don't need to develop computers that are as good as today. 1980s computers will do provided that we have enough of them and that almost all of them are working on finding that number.

Can I nominate this thread as the best thread ever?

I was laughing so hard on public transit on the way home today and people thought I was crazy. @rojo @wejo, please make this thread win a prize or something.

Its funny enough to be entertaining and thought provoking enough to be worth discussing.

People underestimate the rate of progress. Lots of people work with metal and glass. Early efforts in electricity were not very precise.

Fundamental physics and E&M, etc, would be preserved. There are enough smart people.

I like the 250 year timeline.

Harambe wrote:

People underestimate the rate of progress. Lots of people work with metal and glass. Early efforts in electricity were not very precise.

Fundamental physics and E&M, etc, would be preserved. There are enough smart people.

I like the 250 year timeline.

I think you are over optimistic in assuming knowledge will be preserved. How will this knowledge be preserved? The first few decades will be chaos. The new class of rulers will be warlords who will have little time for academics. Their main emphasis will be for survival and fending of other tribes from hunting and gathering grounds. Strength and fitness will be the prime asset, not intellect.

The key technology to develop will be paper. As that is the only way detailed knowledge can be transferred. Even if a tribe did have the fortune to be in an area with abundant food supplies and no competition for those supplies, and also had a benevolent leader who would permit tribe members to not work and instead write down knowledge. Realistically, how much knowledge would that tribe of 200 or so people have? Would they have experts in mining, smelting, forging, casting, welding, metallurgy, manufacturing process, all the technology necessary just to make steel.