If true, that ends up meaning that alien civilizations are short-lived, right? That doesn't bode well for us.
If we imagine that in the last 5 billion years, there have been a good solid 10,000 post-industrial civilizations, and each of those civilizations has lasted 10,000 years (in the post-industrial stage where they're detectable), then that implies that of the last 5,000,000,000 years, 100,000,000 of them have been host to a post-industrial civilization: a given year has on average 0.02 currently present civilizations in it.
Now, this hypothesis does probably imply that significantly interstellar civilizations are impossible, since it seems like if you've colonized say 20 stars, what disaster could possibly end your civilization?
(I think the most likely scenario is that we're the only civilization ever to have developed in the Milky Way. Everything else seems like it assumes a lot of additional stuff.)
Unfortunately, war with another civilization.
Like if on Earth nukes were something everyone could cook up in their backyard in an afternoon, we'd all be gone pretty quick.
Not sure that really makes any sense though.
The Killing Star[0] and Flying to Valhalla by Charles Pellegrino are based around the idea that it's natural for a species to annihilate all other sentient species. The characters define three rules that an alien species may be operating by.
Rule 1. Aliens will believe their survival is more important than our survival.
Rule 2. Wimps don't become top dogs.
Rule 3. Aliens will assume that the first two rules apply to us as well.
[0] https://tvtropes.org/pmwiki/pmwiki.php/Literature/TheKilling...
In the book that the OP article is based on, humanity is doing anything and everything to prevent/defend themselves against an alien invasion happening ~400 years in the future. The character who coins "Dark Forest" theory in the book proposes sending a 'spell' (just a signal containing coordinates) to a nearby star, which is then amplified throughout the universe via "Sci-Fi science". This reveals the location of the star, and shortly after the star is destroyed by some comet-sized object moving at the speed of light. It's later revealed that some other civilization listens for broadcasts on every spectrum, decodes them for coordinates, then destroys the ones that seem to have actually been sent by intelligent life.
I thought this made perfect sense - why wouldn't another intelligent species do this if they possess the technology? I personally agree with "Dark Forest" theory and think that we should /never/ make first contact (lest we are destroyed), but if we were to attempt first contact, we should at the very least have a weapon like you described available to us first.
I think the only question we can ask here is "Would we do this if we possessed the technology?". We only have ourselves as an example of intelligent life.
Society probably only functions below a certain level of technological advancement before everybody dies to an onslaught of engineered diseases.
If we can control resource, exchange knowledge and techniques, and reproduce automatically (for instance if we become small electronic machines rather than the current inefficient chemical process we are), "war" might probably sounds both ridiculous and totally ineffective, both to cull us if we're abstract enough, and to cull potential enemies, probably just as impossible to reach "physically".
Perhaps we can shake off many emotional components of war (which would make war an irrational option in many of the cases that our monkey brain would have been dragged into) but that doesn't necessarily mean that war itself would be eradicated
Also, multi-species symbiotic relationships are quite common in the animal kingdom. It would be surprising if that weren't true at other scales (and if it were limited to the sci-fi trope of "worker species, soldier species, leader species").
Selective pressures that permit the emergence of cooperative behaviour require participating individuals to exhibit a variation in behaviour and those who cooperate result in having a higher fitness in the environment than those who shun cooperation. The selection effect operates on over the whole population and over times that are longer than the life span of an individual.
An individual that is implementing what ultimately will emerge as the winning strategy, may on average be better off, but it can (and it will) be also often worse off.
Depending whose existence you're optimizing for (individual or species) changes the framing of what is the optimal strategy.
An existential risk for a species changes the framing of what is rational to do quite a lot.
This is the sticking point for me.
The rocket equation, energy being quadratic with velocity, and the impossibility of perfect efficiency (and, possibly, limits on material properties) constrain speeds.
That means it takes a long time to get between stars. A long time.
Which means if you venture between stars successfully, you're adapted for life in interstellar space. If that's the case, why would you go down the gravity well? There are lots of asteroids and comets to use in Oort clouds and between stars, and those down-well enviroments are hostile.
Climate change will make parts of the world inhabitable that are currently populated by humans. It will also result in crop failures, which will cause famines. In some cases formerly native crops will no longer be supported by the changing local climate or farmland may become completely unusable. Potable water will become harder to source. Water contamination is a source of many deadly diseases.
Even if we assume most of the deaths will be concentrated in places like Africa or the Indian subcontinent, the global economy relies on these places for resources and cheap labor. People in ongoing climate catastrophes also don't tend to stay put and die in an orderly fashion, they become refugees or riot against their governments. Things can get politically messy even in the nations next door as humans tend to be uncomfortable with political chaos and mass deaths.
But unlike the Spanish flu, or the potato famine, or COVID, climate change is not a temporary blip that happens and then goes away. If all the carriers of the plague have died, nobody dies from the plague unless they get infected handling the dead. Famines can starve millions to death but once there's another harvest the survivors have food again. Climate change isn't like that. If climate change creates a drought, that's not just a drought, that's now dry season and it will be dry season every year from now.
There are currently 7.8 billion humans. There's absolutely no reason to believe climate change can't kill billions, especially once it's managed to kill the first hundreds of millions.
Keep in mind that it's not about "addressing" climate change. It's not a moldy bathroom tile that you need to clean up or replace before the mold spreads everywhere. It's a fire our entire way of life is fueling every single day. We know what needs to be done to slow it down to survivable levels (or at least levels that are lethal for less than 1% of us) but we can't just pass legislation or appeal to personal responsibility to do that because it involves changes that would be economical suicide for anyone doing it alone. The world economy is playing a game of chicken with each other and nobody is bluffing.
[1]: https://grist.org/climate/how-many-people-has-climate-change...
Additionally, the entire worlds population at relatively sparse city density (say, Houston) can fit in like 1/3 of the United States.
That isn’t to say that climate change isn’t a big deal. It is one of the biggest deals and quite grave. But you don’t really propose any solutions. What you allude to though won’t happen, that everyone works together to address the issues. My speculation is that if our technology doesn’t progress fast enough, billions will die, but if tech does happen to progress fast enough then that will be mitigated.
That isn’t to say that the world couldn’t use a strong reduction in population. But given that we are causing this, I feel particularly bad for the wildlife whose habitats will be unlivable to them through no fault of their own and not through natural processes.
Do you mean they are guaranteed to discover another “realm” and move to it?
Why? It might not be possible, no matter how much physics one knows. Or do you take the Fermi paradox itself as a proof of the solution?
We may not talk to them simply because it's both incredibly expensive and will yield nothing more than "Yup, we're stuck here, so are you".
AFA we know we've been insanely lucky up to this point (as earthling life we went past multiple mass extinctions, we got multi-cellular life, multiple brains iterations, a society which still didn't wipe itself out etc)
What makes it more likely for the filter to be ahead of us rather than behind us?
If we can't make the complete transition to renewables in the next thirty years, it's game over for a VERY long time. Future civilizations won't enjoy the benefit of Spindletop. Cheap energy sources won't be available near the surface of the crust for another > 50 million years.
We won't go extinct, but it will be the 18th century for a very long time and nobody will leave this rock during that time.
The Great Filter is right here, in front of us, in our lifetimes.
Wrong. We already have one: nuclear energy.
Looking forward to the fleet of electric concrete trucks carrying electrically-manufactured concrete loaded with batteries that were produced with lithium carbonate dug out of the ground by electric excavation rigs.
All of this construction work will also not be disrupted by any social unrest resulting from 3 billion people starving to death because the Haber process no longer has enough cheap feedstock to sustain modern agricultural processes.
Thanks for educating me.
Few people expect to die at any specific day, they just know they will die at some point because mortality is a given.
Does seem likely that on an extremely long time scale, we need to get multi-planetary, which is "realistic" if we give a reasonable time frame of, say, 10,000 years.
As far as the sun dying, that's beyond even parent point's timeline. This is very things start to get questionable if we never get to even .1 of c (e.g. Project Orion "realistic" estimates). Alpha Centauri is relative close at 4.something ly, but other "potentially habitable/useful" star systems are way out there.
This is a strange claim I see repeated over and over, but it has very little evidence to justify it. The only piece of evidence people present is:
> people had colonized the whole planet, except for Antarctica
This is true of a fairly large number of organisms on Earth.
On top of this humans have only been around for ~200,000 years, that's not long at all. Humans have not survived a single mass extinction event.
So far we've seen humans travel around a planet that has been relatively stable for that period of time. There have been plenty of species that have traveled around with us that didn't even need to rely on extra tools, clothing or the use of energy to survive.
Humans share several vulnerabilities with other megafauna that have all gone extinct. A major one is a fairly long gestation, plus small number of offspring per generation. Human young likewise need tremendous amounts of care and energy to raise to mature adulthood. Additionally human have fairly high energy requirements to support their complex brains.
We've seen exponential rise in human population only because humans have had access to excessive amount of non-renewable, high-energy density sources of energy.
It just happens that humans have lived on a planet that has mostly been within survivable temperature changes, with historic climate changes happening on time scales that lead to easy migration. As you pointed out, the one continent that does not have an environment that supports human life remains empty.
Humans can't survive a wet bulb temperature of 35C. Until just recently we never saw that temperature on this planet. As we see more and more places reach that temperature more often, I suspect we'll see how frail human adaptability is.
Is it though? How many other large, multicellular, organisms live on every continent without humans having brought them there?
That is because we possess multiple different ways of adapting to our enviroment:
genetic
during childhood
acclimatization
culture and technology
This link provides a nice summary: https://www2.palomar.edu/anthro/adapt/adapt_1.htm
That's because we have had ready access to insanely abundant high-energy density source of energy.
The non-fossil fuel supported carrying capacity of the planet for humans is estimated to be somewhere around 1 billion people. When the fuel runs out (if we don't cook ourselves first), that will collapse.
It is nothing intrinsic about humans that have lead to our recent success, just access to lots of nearly free energy.
edit: why the downvotes? Is there even anything controversial in these statements? HN's fear of bad news is getting out of hand.
I also strongly believe that we could cover all our energy needs with renewable sources within a few decades if we really wanted to (even assuming no significant advances in tech), and this seems mostly non-disputed to me (because that is literally what nation-states are currently planning/doing).
> Is there even anything controversial in these statements?
Yes. Your statements seem not credible to me and you cite no sources.
To see the powerful impact of fossil fuels on carrying capacity you'll notice there's an important inflection point around 1920-1930. This is because of the advent of the Haber process[1] which allows us to use fossil fuels to create nitrogen based fertilizers.
Lest you doubt the impact of the Haber process just look at trends in corn yield per acre since then [2]. It's truly remarkable. Additional gains there are from other industrialized, fossil fuel driven agricultural process.
The Haber process requires hydrocarbons. In the wikipedia article you can see that it consumes 3-5% of the worlds natural gas production and 1-2% of the global energy supply.
We have completely disrupted the natural nitrogen cycle [4] and so would be unable to produce anywhere near as much food without fossil fuels. Because we have disrupted this cycle it's not even obvious that we could go back to a world of pre-fossil fuel agriculture.
So those are just some bit of information about my claims but let's take a look at yours:
> we could cover all our energy needs with renewable sources within a few decades if we really wanted to... this seems mostly non-disputed to me
This is wildly disputed, and I don't know anyone who credibly believes this without invoking "magic" future technology.
For starters we haven't replaced fossil fuels with "renewables" at all so far. We've just used them to supplement our energy needs. You can see here [4] that global fossil fuel consumption has continued to rise.
Then it is important to separate electricity from the more general subject of energy. Currently only 20% of global energy usage is electricity generation [5]. So even if you replaced the entire grid with renewables over night you would still be missing the vast majority of energy demands.
We currently have no viable pathway for renewable energy in transportation. Alice Friedman has more notes on this than I could ever fit in a comment [6]. Transportation inherently requires high energy density fuels, and outside of passenger vehicles, battery technology does not have the density required for industrial shipping.
It worth looking at our national energy flows to get a good sense of just how little of the energy we use comes from renewables [7].
But even if we look just at the electrical grid, in the US, we have some very obvious problems with "all" our needs. As you probably know, wind and solar are intermittent power sources that requires fossil fuel powered "peaker" plants to provide energy in down times.
This had two problems. One you need energy storage technology that we do not currently have (you cannot use grid scale lithium batters, pumped hydro has geological constraints, molten salts only work with concentrated solar, compressed air requires decommissioned oil field, etc).
The other problem is that even if you had perfect storage you need to now more than double the total energy production so you can fill those batteries.
The should be enough sources for you to get started, but I have feeling I'll still get down votes and "hand wavy" explanations of how it will all work out.
0. https://en.wikipedia.org/wiki/World_population#/media/File:W...
1. https://en.wikipedia.org/wiki/Haber_process
2. https://www.agry.purdue.edu/ext/corn/news/timeless/YieldTren...
3. https://en.wikipedia.org/wiki/Human_impact_on_the_nitrogen_c...
4. https://ourworldindata.org/grapher/global-energy-substitutio...
5. https://www.iea.org/reports/world-energy-outlook-2019/electr...
6. https://www.resilience.org/resilience-author/alice-friedeman...
7. https://flowcharts.llnl.gov/content/assets/images/charts/Ene...
> I have feeling I'll still get down votes and "hand wavy" explanations
Let me turn this around: you are getting downvotes (not from me) because your 1 billion population carrying estimate in a post-fossil age is implausible and borderline disingenuous:
1) It assumes that pre-industrial agricultural output is the maximum that our planet can sustain. Which is completely off for a multitude of reasons:
- Genetic improvements to cultivars still fully apply
- Pesticides won't cease to exist
- Automation in harvesting/monitoring also won't go away
2) There is no reason to assume that we're anywhere close to peak sustainable agricultural output, neither in pre-industrial times NOR now.
3) Furthermore, it implies that land utilization, cultivar choice and consumer behavior in general would stay similar/comparable regardless of cataclysmic change in supply/demand (pricing). Which is obviously wrong: If avocado price went up to 50$/kg then people would just put potatoes on their toast instead, and total agricultural output (in calories) would "inexplicably" increase.
Regarding power:
Renewables (solar/wind) are a perfectly fine source of primary energy. Storage/grid stability does not depend on "technology we do not currently have"--Batteries and inverters are perfectly usable, mature technologies--but right now slapping down natural gas plants is simply cheaper. This is exclusively a matter of price/ROI, and installation could be jumpstarted immediately if there was the political will to pay for it (and thats not blaming politicians exclusively to be clear--average citizen is simply unwilling to pay 1$/kWh right now for residential electricity).
> Renewable energy in transportation
Friedman selfdescribes as "energy sceptic" which is already...unfavorable... to me and after stumbling over "running out of fossils is gonna solve climate change better than anything else" (transcribed), I gave up on the author completely;
Viable pathways are:
- Batteries
- Biofuel
- Fuel cells
- Hydrogen in combustion engines
We literally built all of those already, but same story here: It's less cost efficient than burning diesel right now, so why would anyone do it.
I agree it's off because we've done significant damage to the biosphere since industrialization. As I've pointed out we have disrupted the natural nitrogen cycle.
If we where to immediately rewind our population back to 1850 and try to life that lifestyle we would have a much harder time since we have depleted natural resources. We cannot go back because we the earth would not support us the way it once did.
> There is no reason to assume that we're anywhere close to peak sustainable agricultural output, neither in pre-industrial times NOR now.
Our entire current agricultural system relies on fossil fuels, so I agree, where nowhere near close... we're way past.
> Viable pathways are
- batteries: not for commercial transport, the energy density is still way too low. Your battery becomes your cargo. Modern global trade is impossible in a battery based economy. Nobody that is serious on renewables will disagree with this, they will claim that new battery technology is going to solve this.
- Biofuel: require more energy to make they they provide [0]. So again, not only do you need to double the grid to handle intermittent power, you now need to expand it by the total biofuel energy required times 1/efficiency, so we're looking at at least tripling our current power output and trying to do it with only renewables. Please tell me how much silicon and lithium it would take to build a grid that large in that sort of a time span and you'll find it dwarf's annual production.
- Fuel cells: same problem again, currently fuel cells are made with coal or natural gas today 95% of fuel cells are made with natural gas [1]. If you want to switch to electrolysis you come up with the same problem of having to double our current grid power.
- Hydrogen in combustion engines: I'm not sure how this is different from hydrogen fuel cells, but the hydrogen production problem is the same.
Please if you want sources, provide some of your own. Come up with some back of the envelope estimates on the total grid capacity needed to cover 100% of our energy needs. Then do some research on the energy costs to produce solar cells at that scale (or wind farms, hydro is already near full capacity at least in the US).
I know you yourself don't really believe what you are saying. It's based on no research, you have provided no meaningful sources, and even the most die-hard solar/renewable proponents realize that grid scale storage is still an unsolved problems. What you have given are "hand wavy" explanations without sources, exactly as I expected.
0. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7320919/
1. https://www.energy.gov/eere/fuelcells/hydrogen-fuel-basics
It seems far more questionable to assume we won't risk extinction in the geological near term. The parent is downvoted more out of existential fear rather than an honest assessment of the situation.
As for us, I don't doubt the likelihood of a serious mass extinction, including possibly a severe drop in human population, but I can't see it being so severe as to cause an existential threat to us. No other species on this planet has had the ability to change the environment to suit it, or the ease of mobility to move where they can survive. Short of earth being entirely incompatible with complex life on the surface, I don't see humanity disappearing because of climate change.