> We are consuming nonrenewable (or very slowly renewable) resources at an unsustainable pace. Coal, oil, and gas are finite resources...
It's hard to overstate just how much fossil fuel there is out there compared to demand. Beyond that, we're becoming more efficient at an even faster pace than we are using it.
> Even if there is a lot left, there is not an infinite amount left.
Plenty of nuclear, solar, wind, hydroelectric, etc.
> We are converting rainforests, which produce the majority of our breathable oxygen and consume the majority of the carbon dioxide, into land for farming or housing.
This is happening in the 3rd world, and will be arrested by minor effort on the part of the 1st world if it is ever made to care enough. The idea that we are going to run out of breathable oxygen is something that only a journalist could believe.
> Our population is growing so fast that our ability to provide food for each person will be in serious doubt within a generation, despite all of our scorched-earth efforts to extract more and more sustenance from the planet.
Whoa, has somebody been reading population projections from the 1970s?
> Meanwhile, climate change is threatening major coastline developments, some ocean ecosystems are in all-out collapse, and biodiversity throughout the globe is plummeting.
3 separate, though major issues, but none of which threaten civilization.
> We are in the midst of a mass extinction caused almost exclusively by our own actions. Who knows how bad things will get before we bottom out?
In my youth these sorts of people just joined doomsday cults. (The Jehovah's Witnesses are still in operation if anyone is looking. I'm sure that there are others.)
Real threats to civilization exist. The Earth's biosphere has been wiped out several times by large rocks from outer space. It seems likely enough however, that if we can survive the next 1000 years (order of magnitude), we'll have enough technology to create cross-planet ecosystems that are not so threatened from a large rock wiping out any single planet.
Our economy today is possibly already too large for our long term survival, and event if it isn't I'd rather we avoid crossing the threshold unknowingly.
But off course no one ever died in a fire they themselves had started. Let's keep on fanning the flames.
I suspect lacking a good surface fuel source might be more limiting. Imagine the difficulties making metal tools with no wood to burn.
It's quite possible that we stand where we are as a result of a very long series of very unlikely events and conditions.
But we really just don't know.
I am reminded of those few galaxies in Bootes Void who legitimately wouldn't be too wrong in thinking their galaxy was the observable universe until they could see beyond the dark.
Gasification can be used with any organic mater, wood and hay are pretty common materials.
It might be slower but it would still get you there.
I believe that there is some speculation that plate tectonics is necessary to sustain the sort of environmental stability, over long periods, believed necessary for complex life to evolve.
I think that is speculation at best. Looking just at our local system, Mercury appears to have active tectonics, Venus is now believed to have active tectonics, Earth obviously does, and Mars is believed to have had them at one point if not currently. And there seems to be evidence of both tectonics and liquid water on Titan.
The galaxy is populated, much like Earth. The power controlling our region has a policy of leaving us alone. End of story.
This requires no great filters or fantastic coincidences, and assumes galactic society is organized much like Earth.
Another theory that doesn't require a great filter: The distribution of life may not be equal across the galaxy if it's truly random, we could be in a local minima and never meet another civilisation by the bad luck of where we are.
Never thought of the practicalities of that, so thanks for bringing it up.
I think you're overstating things. Sure, they wouldn't be able to watch the Superbowl at the same time or hold elections in the same decade. It would be a very different and slow moving kind of civilization than what we know.
But I don't see how that means it can't exist, in some form.
Or perhaps the good luck of where we are
A more interesting answer is they are simply horrified or disgusted: look up "They're made out of meat!"
Is it that hard to believe that our local aliens ignore us for the most part, that sometimes we see their spacecraft and mistake them for natural phenomena, and when one of them approaches illegally if they land in the wrong place they just get killed?
Or they just don't care to visit our solar system because there's nothing of interest here. I'm sure you can imagine a 18th century European surveyor sailing past a bunch of new islands, noting them on charts and tossing in the description "contains no resources" and then moving on.
Or maybe they've come, but only in very small numbers. They radio home and leave for the next system to explore.
If we assume that an advanced civilization will develop machine intelligence on a large scale with efficient processors and vast energy resources, it's possible that they've already fully explored the nature of worlds such as ours, and they don't have any reason to monitor them further.
Even a slow moving star hopping civilization should have spread across the whole galaxy many times over by now.
The 18th century surveyor skipped some islands, sure. But by now they're all accounted for.
When has earth society ever successfully left something new and foreign alone?
If there is a 'galactic directive' to leave us alone, it's because we were seeded here. I.e. we are the aliens, and being observed as some sort of experiment
Planets are common.
Given the speed with which life evolved on Earth it's also probably common.
That leaves four barriers:
1) Multi-cellular life. Looking at Earth that took billions of years--it's likely a hard barrier to cross.
2) Intelligence. It took hundreds of millions of years but there were a lot of steps, this doesn't seem like evidence that it's all that hard.
3) A term not in the Drake equation--effective lifespan of the biosphere. This is the main argument of the Rare Earths hypothesis. Most planets do not remain stable enough for intelligence for long enough for it to arise. Looking at our own world we can see that we have already used up 99% of that time, we barely eeked under the line. (We have only about 50 million years before solar warming can be countered by lowered CO2, after that we have several hundred million more habitable years but they won't be friendly to big, slow-evolving animals of the sort needed for intelligence.) This very well might be a substantial barrier.
4) Intelligence is destructive, species that can communicate do not remain in that state for long. Note, also, that a species that can communicate probably can in an eyeblink of galactic time do interstellar colonization. Even by slowboat they should spread across the galaxy in at most a few tens of millions of years. Also, once a species has reached this point it would be almost impossible to destroy--thus we can conclude no species in the history of the galaxy reached this point.
The product of these terms must be infinitesimal. Either we have been extremely lucky so far, or we are facing an almost insurmountable barrier to survival in the near future.
This article framing the paradox in context of climate change is simply doing the same thing, framing it in context of our most pressing existential threats of the day. Also, like Sagan, implicitly overstating the impacts of those threats to us as a species.
Its a useless exercise and brings no new information to understanding the Fermi paradox and doesn't bring us anywhere closer to resolving it.
Edit and clarification, since I think some people take issue with what I wrote above:
Existential threats I mentioned, nuclear and climate change, are in their worst possible realizations will be planetary wide catastrophes which have the power to cause us, as a species, enormous harm.
But they do not measure up as the existential threats implied by Sagan or author of this article : so they are not answers to the Fermi paradox.
I am looking at these two things strictly from POV of the paradox, not as pressing policy issues.
 https://nickbostrom.com/existential/risks.html / https://wiki.lesswrong.com/wiki/Existential_risk
Yet the one sample we have, us, doesn't fit the pattern
1. Civilizations have a short “technological” shelf life eg when they can send and receive signals, say 200y
2. They are spread apart by space and time by natural distribution
3. The chances of two of them overlapping (eg civ a is transmitting during a time civ b will hear it) is very small
So nobody ever hears each other. Maybe If we were around for 5000 years we’d catch one.
But we won’t be.
That line of reasoning started with, "If we knew then, what we know now, would we have claimed the new world for conquest?" There are examples that we would not, for example protecting Brazilian indigenous peoples who have not contacted the outside world from being visited by people. Would "modern" western Europeans wait for the native Americans to sail east and meet them? One could hope they would. With a careful understanding of infectious diseases and respecting their traditions and culture.
It is arguably the case that we have lost much in terms of culture, ideas, and diversity through genocidal colonialism. Would a more enlightened civilization decide not to go there? I would like to think so.
Waiting? For how long? How can they tell that we've passed the threshold of being in the group of species that won't off ourselves?
I'm more inclined to think that we may not be all that interesting to more advanced species or as the author writes that our time-span simply does not overlap with the time-span of any intelligent life close enough to signal us.
Even though there are plenty of vague handwavy theories about warp drives with exotic requirements like negative mass, the Fermi Paradox seems to suggest that no solution for FTL is practically feasible.
Most of the book is a summary of life beginning on Earth, followed by a re-thinking of the Fermi Paradox taking into account our own anthropocene, and finishing with some numerical experimentation.
What if we have met them, but they routinely sedate their subjects and administer a memory block?
What if we have met them, but only as random test subjects because they have no respect for us whatsoever, so they see no point in trying to establish diplomatic contact?
Besides, it's not like we have a world government yet. "Stupid primitives."
And yes, someone in a vessel traveling near-light speeds won't age all 4 of those years. But we do. It will be, for us, 8 years before someone hops to the next closest star and back.
Same with information from an unmanned probe. Even if we can beam it back at light speed, it will take years to get back here. And we're talking about going somewhere we know about.
In terms of exploration, forget it. Space is kind of infinite. Not knowing if there would be something when you get there is going to be a waste of years back here on Earth.
Interstellar travel, if it is happening, is being done by robots.
That AI is possible. We don't understand intelligence. We don't. To presume we could recreate it is, at this point, wishful thinking.
And even giving you AI, they would have to decide that it's worth it.
Let me just straight up ask, what's the practical use? We're interested in interstellar travel because it's a way for us to expand our species. A completely artificial life form with an effectively eternal lifespan has no such concern.
I haven't bothered to read it, but it is available online:
I'm content to mostly limit my exposure to such topics to having my mind periodically blown by my adult sons, then fairly promptly forgetting most of what they said. Physics just isn't really my thing.
For example, an interstellar traffic accident at near light speed of a sufficiently massive object would cause a lot of damage to a planet.
The Fermi paradox posits that there should have been huge numbers of spacefaring civilizations for millions of years before mankind evolved. If you postulate a candidate great filter that lies ahead of humanity then it must have filtered out every single expansionist civilization in our galaxy up till now.
The solution that makes most sense to me is simply that we did the stats wrong when combining estimates of the factors of the equation, and our best guesses predict very few other civilizations: https://slatestarcodex.com/2018/07/03/ssc-journal-club-disso...