Abstract / bottom line:
The dark vision of a deserted planet Earth  will inevitably become terrible reality. – The scientific question is when.
This is my answer to the Fermi Paradox (my sceptical calculations if you will) in five paragraphs about bad intentions, interstellar space flight, eugenics in the 24th century, interstellar governance and emptiness of transhumanism.
The most evil will prevail. (Preface)
People like to deceive themselfs if it becalms. - Concerning the future of planet Earth we have the Canadian astronaut Chris Hadfield who is payed for telling comforting tales we like to hear.
First: He describes strikingly (video #t=6m12s) how the political judgement of a human being changes when watching Earth from space, orbit by orbit. Hadfield deems this a liberation in thinking, a relief from narrow-mindedness and prejudices.
– But the opposite is true. People conceive what they see and suppress what is outside of their field of experience. In this case they become idiots in the question what makes the political world go round (idiots in sociology). Hadfield's wish is this: send everyone into orbit to let them see the whole world as one single place.
Subconsciously Hadfield considers the whole world US property (he is practising hypnosis when he says "we" and "mankind"). He tries to make people blind to today's causes of war on earth - the craving of the super power. (Yes, US power will prevail, but for now Hadfield gets the 'inadequate' grade in propaganda.)
The second inability (unwillingness) to find solutions to save planet Earth is to think in categories of technology and not of social sciences (that's just like North America).
Hadfield talks about electric cars, nuclear fusion and other fob-off arguments. 
In fact the real topics of a sustainably habitable earth are these:
- no consuming extraction of oil, coal, ore etc. at all
(but exclusively recycling, recovery of metals etc.)
- no remaining CO2 emissions at all
- no demographic growth at all (see also Hoover Research)
- no acid rain and acid oceans at all
- no overfertilisation of soil and streams at all
- no waste landfill at all
- no reduction of glacial ice at all
- no reduction of forest at all
- no reduction of biodiversity at all
- no diesel-engine-driven mass transportation by sea and airlift at all
As a hundred-percent execution this is impossible (see my criticism against E. O. Wilson  ). But everything other than hermetic circular economy (the list above) will lead to an early death of planet Earth in a few hundred years.  
The restrictive circular economy wouldn't mean stasis of mankind nor would it be the end of progress in technology, science and personal liberty. But it would halt the explosive and uncontrolled growth of the human factor on earth (and yes, it would halt the big incitement: profit from consumption). - The difference would be like that one between today's fast cargo ships and slower but futuristic sailing ships for cargo transportation (from a technical point of view).
In terms of sociology and politics it would mean to overcome the western model of society and to establish a Chinese-like global Central Committee that dictates everything that is related to global and long-term interests of mankind (a dictatorship on behalf of the coming generations – humanism in preference to transhumanism).
And even that wouldn't prevent from wastage by degrees of planet Earth. - But it would safeguard the evolution of mankind for tens of thousands of years.
– The one big question is: How to ensure the power of this dictatorship stays limited to its purpose? The other question is: How ever can such a Central Committee gain power to enforce its order globally?
The answer is: in no way. We all know abdication of power only happens in this (capitalist) world when it's over (when it's too late). So the turn into a global responsibility will not happen.  Instead they will feed us with hopes of exoplanets – exoplanets (you're not going to believe this) no human alive will ever reach (if any: posthuman incubators, contagion capsules).   
Chris Hadfield's third demagogy playground is global warming. He knows it's not exactly honest when the man with the probably biggest CO2 footprint under the sun complains about gas emissions. His employers as well (Hadfield is i.a. retired colonel) don't want to hear something like that. So he accepts to appear in interviews hedging and even cynical [a] [b] - just not to tell downright lies.
He knows his situation is sick. But I doubt he knows the size. Whitewashers of his kind are efficient in promoting the hidden death of mankind. – Yes, I mean it. Realistically it's inevitable: the most evil will prevail.
Interstellar space colonization means carrying genes to safety
I estimate it will happen in the late 24th century: Man is leaving planet Earth and the solar system. Earth had become widely uninhabitable, people on earth had died in apocalyptic numbers and in the end mankind as we know it had died.  What remains is dead Earth and dead Moon as the initial point for the observation and control of a number of targeted exoplanets – huge telescopes, communication laser emitters and the post-human elite that manages the whole thing.
Looking back from this deserted 24th century it becomes clear, capitalism was a duplicitous promise. You can't have both, the free play of forces (the free market) and at the same time a majority decision where the evolution has to go. You can't have a battle for profit from Earth's resources and at the same time preservation and integrity.
So, concerning the future of planet Earth, what in the first place is the result of the inability of capitalism to preserve the foundations of humanity will be in hindsight declared to be the mission:
To sacrifice Earth and mankind for space colonization.
(Of course it is the biggest deception ever. Who sacrifices Earth and humanity has no goal and no integrity at all — does not deserve and will have no future at all.)
I wouldn't call it mankind or humanity what spreads from Earth to a number of exoplanets in the galaxy. It's if anything disqualification of humanity from genesis. It's the triumph of the genes of some separated among us, as planned ahead i.a. by Stephen Hawking. (see "Hawking - Ideas of a Pervert"  )
What technology the project will use is not important for this analysis. (Perhaps conserved oocytes, artificial uterus and robot nannies after a thousand years of space flight, conserved seeds for automated greenhouses, the conserved microbial metagenome etc.) – In the first place it is about perpetrators who carry their shady effort to safety and abdicate their responsibility.
In the early 21st century the International Space Station ISS was already quite expensive ($150 Billion). The project of interstellar exodus will be exhausting to death.
It will burn out all industrial and intellectual resources on the planet for centuries to fire these capsules carrying the entire knowledge, technology and genetic heritage of mankind into space.
— It is hard to understand and must be forced by desperation: The living mankind on Earth gives up itself and its home planet to spread the genes of those who planned its demise.
Panics and Eugenics
Without having an exceptional situation and existential crisis on earth it would be impossible even to think or to plan the interstellar exodus, much less to put it into practice. It would not be enforceable
- to exploit all resources and working power on earth for the one single purpose of space colonization
- to breed the successor of man from some filtered out humans
- to abandon humanistic core values.
What would it feel like to have someone as a colleague who was born with an optimized genome? Or to have him in a TV show - two meters tall, much faster thinking than you and more complex, so he has it down cold to be entertaining - and he can really be funny (at your expense). His teeth are whiter when he laughs at you (knowing he will outlive you by two hundred years). – I guess it would be horror.
But no worries! He wouldn't be set free/ transhumanism wouldn't start before mankind has died.
How about humanistic core values when the space capsules will reache their targets? What if there occurs a technical problem or let's say illness? - Some children will have to be switched off. (Care is for the success of the project not for the individual.) – That sounds like the most terrible Nazi ideology - and it is. 
Otherwise the space ship would have to be that huge it would be unaffordable for ever, the flight would take thousands of years and would never take place.
So, the first and most basic requirement for interstellar space flight is to induce the exceptional situation and existential crisis for mankind. Purposeful demoralization has to be achieved - by appearance of the enemy from outer space (the Alien) or by the self-induced total environmental catastrophe.
Since the 20th century there are experts in staging destabilisation on the one hand and singlemindedness on the other. It will be not that difficult (just watch TV and it works). - And then transhumanism begins: experiments on human genes  and selective breeding of what will set out on the interstellar journey.
Enrico Fermi asked looking up to the starry sky: "Where is everybody?"
– Most likely there is nobody in this galaxy.  Alive organisms are perhaps not that rare in the universe but with regard to places where evolution can go that far planet Earth is obviously the first.  (And what happens in other galaxies will remain speculation for ever.)  
So it seems there is no limit for the genes of the chosen ones in this galaxy. - But what will the future be? What are the options to spread these genes over the galaxy? Will it be a release of a subdivision of mankind into a remote and open future? And will the godspeed address –aimed at the human seed in the capsules– sound like this? :
"Good luck! In five thousand years we will meet again. Perhaps then with opposing precepts what humanity should be. So, please, stay peaceable!"
– Of course it will not. There will be no such thing as "free subdivision of mankind" or "open future". Totalitarianism is the first premise.
Today's difference between Russians and Americans is minimal compared to five thousand years of independent social change on exoplanet colonies (and guns will be bigger then).
So, consequently space colonization will be a mission under total political bondage, unbreakable for all time. – The costs of the mission exceed any quantifiable scale. So it has to be worth while for someone.
For the elite race on earth (when the population has declined from 10 billion to a few hundred thousand) the former so-called mankind will appear in memory as an awkward excess of the past. - The decline was caused by the collapse of the ecosystem Earth and by the dead acid oceans. But the survival of the chosen few was managed by the institution Five Eyes and its databases (fictionally - but still very likely). We all know what NSA/ GCHQ is: a dossier for each person on earth, biometric data, personality structure, genome, basic convictions, a mark for valuable humans (… the Nazi dream came true).
– The collapse of the planet at the right moment was almost as if it were planned.
5EYES started in the 20th century. Four centuries later it will probably bear a different name. The task and the means  will be different: to control the social life on multiple planets now. – But the principle will stay the same: letting the dream come true - the dream of total, everlasting and world-spanning rulership by the chosen – global dominance.
It will be the triumph of the chosen
Will it? I guess everyone who shares the vision of the chosen ones knows how their augured story goes on in space. – I don't and I don't want to.
Today states become ghetto states where drones fly overhead. People branded by Five Eyes get killed by drones. - But is any sense in it? Isn't it empty in itself for the ruling elite to be "chosen".
Tomorrow people will know the truth looking up to the starry sky.
"It would take ten million years to walk to the next star. But even there the same micro drones fly and control all social life. - The prophecy has accomplished. It is doom."
This is sea change in the idea of redemption of man.
From "Lord. I can't escape. I am weak." to "Lord. I can't escape. There is no outside, no heaven above."
Is this doom? Yes. Even for the chosen.
 The origin of the headline is strange. The complete quote (from Mein Kampf) wouldn't conform to my stance at all. Nevertheless I use this quote because the topic of my blog post is totalitarianism, race, killing and death. I write against racism - in particular against global dominance of a race.
 Hadfield: "The same driving, restless intellect that created the problems can minimize and even reverse them."
This calculated optimism doesn't ask what impels the restless intellect. - What if there is no interest for a reversal? A system of forces can lose its balance and come to a halt (like an anaerobic dead zone in the ocean). That is not technology. It's sociology, the system itself.
(See in my article It's never the technology but the interests)
 In 2009 I wrote: "What mankind is: a clutterer in his studio apartment called planet Earth who suddenly discovers his toilet has no drainpipe and his window can't be opened for ventilation."
 I appreciate the work of Jørgen Randers. - At one point I disagree with his theses: the ability of democracy and competition to save planet Earth.
Take Emissions trading which was sabotaged and did fail. – Karl Marx would say: failed following a set pattern (of capitalism).
 Stephen Hawking in an interview, 2001: "The human race will not be safe before it has found habitable worlds in interstellar space. Darwinist selection [on human beings] works too slow. The only hope to this effect is in my view genetic engineering. It will be a long process. You have to wait about 18 years per generation to see the effect of genetic modification. But we should still take this path to keep our superiority."
(The quotation is not literally. It was translated and translated back.)
My comment on Hawking's attempt in eugenics was in 2001 this: "In breeding, any result that does not conform the breeding target has to be kept away from procreation (at least in this case kept away in a ghetto from the future of mankind). Considering this Hawking's idea is about crime against humanity."
(Reasons enough to call Stephen Hawking a pervert. - What absurd theses Hawking published in fundamental physics is analysed in my paper The Universe as Manifestation of Sense.)
 Still today I'm surprised how easily some ideas from the Nazi-1930's made it to the 50's (with a slightly different label) and to this present day. I was three years old when Hannah Arendt wrote: "This future man, whom scientists tell us they will produce in no more than a hundred years, seems to be possessed by a rebellion against human existence as it has been given, a free gift from nowhere (secularly speaking), which he wishes to exchange, as it were, for something he has made himself." (Hannah Arendt, Human Condition, 1958)
 In 2009 I wrote: "The absence of the extraterrestrials is either worrying or final."
 If they really find somewhere a rat that can read and write (e.g. "FUCK 5EYES" on a protest banner) they will wipe it out. (No, of course they will save it in a nice reservation, they will gaza it.)
In 2009 I wrote: "Where is everybody? - The alien with the only impetus to rule and to oppress is already there. It is man."
Addition 2018-06-01: My answer to the Fermi Paradox ('Man is the first and man will oppress.' see above) was seized on by Alexander Berezin, theoretical physicist from the MIET in Russia, in his paper "First in, last out: solution to the Fermi Paradox". (Sadly he forgot to mention my work.)
An earlier and hugely popular attempt about hostility in outer space is "The Dark Forest" theory by Cixin Liu in his Three-Body Trilogy (review by Dan Wang, 2016 and review by Nick Richardson, 2018).
Cixin Liu says in the afterword: "The stories of science are far more magnificent [..] and even emotional, compared to the stories told by literature." – Maybe it's the translation but that's wrong. It is nature and evolution what Cixin Liu is praising, not science. The exploitation of science by US ideology is for sure not "magnificent" and Cixin Liu sadly serves illusions about the homemade political background of mankind's catastrophy.
 The article The Fermi Paradox, by Tim Urban (2014, a good summary of the topic) made in my view two miscalculations:
- The basis for the formation of a planet like earth (made of heavier elements) are two or more lifecycles of preceding stars (including the agglomeration period of dust clouds that takes hundreds of millions of years each time). So, earth-like planets can't be so much older than earth itself. (But it's right, even in a tolerance period of only one billion years could happen a lot.)
- Intergalactic space flght would take many million years and is presumably impossible for technical reasons. A reason for a civilisation to spread across galaxies is almost not there and would most notably only relate to the direct neighbour galaxy. So the number of possible contacts is smaler by the factor 400 billion (in Tim Urban's calculation based on a limited bubble universe).
 Technical means to control the one (and only) interstellar state are possibly periodical "civilization unlock keys" sent by "lightyear laser" from Earth's Moon. - But that's speculation. More substantial is the principle: remotely working unbreakable rulership.
 A sceptical blog post by Charles Stross, 2007, about colonisation of exoplanets: "Colonize the Gobi desert, colonise the North Atlantic in winter - then get back to me about the rest of the solar system! "
 My estimation addresses two main points:
- a) In my view it will take much more time to establish interstellar space flight than today's futurologists might think (another 300 years or more).
- b) A civilisation on a much higher level of intelligence and technology than today's will still be biological. In my view for the winner of the final battle on earth the genome will be the core value – artificial (technical) superintelligence (ai) will be not more than expedient.
In detail about a):
Knowing Ray Kurzweil's thesis of The Law of Accelerating Returns 400 years from now are really a huge time span. But interstellar space flight will not be an experiment, not a first step. It will be the all-embracive step into eternity, into immortality of the race (Hawking's thesis). And before that, two kinds of dying have to be experienced.
1. Given that habitable exoplanets already bear life and that alien microbes, mycelium etc. are lethal for man, humans have to develop weapons that 'sanitize' whole planets and technics that inject later the own microbes. That takes time.
2. On Earth the final dying of 10 billion people will not be a discrete event but an age of darkness and horror. – It will take time before the world is absolutely clear and ready for the promised exodus.
In detail about b):
The compelling evidence post-human life will stay biological is this: The human mind ('posthuman mind' as well) and mental health can only exist in social life, in groups of individuals with limitations (e.g. of intelligence). On the other hand structural self- improvement of AI would have no limitation in executing tasks, but it would be in its core antisocial (sociopathic and disturbed, simple: without a soul). – So one thing rules out the other and transformation ("upload of the mind") can't work.
– More on the AI topic see my essay The myth of artificial superintelligence.
 Added 2015-06-23: A blog post by Anders Sandberg sets another illustrative example how people are fooled what the future of mankind looks like.
Sandberg's article is at the first glance a fictional mathematical case study of habitats in space. But in fact its purpose is to plant illusive, misguiding beliefs into a popular dicussion. Sandberg's proposals are about objectives that obscure the real objectives (and consequences) of the western society, they are ideology.
My response to the essay:
Even under best conditions and even in safety on earth man is not able to run a self-sufficient (hermetic circular) system, not biologically ("Biosphere 2 ") and not economically ("2052 ") – so for sure also not in space.
I belief in boundless cognitive abilities of man - as long as it is about thinking and spirit. – Physically and in the real (capitalist) world man is a sewer rat.
Man's intention/ ability is not to "build and maintain worlds" (as suggested in Sandberg's essay) but to live parasitic until the host world collapses.
The job of futurologists like Sandberg is to deceive people over the real future so the exploitation of the planet can go on as long as possible. – Sandberg tries to make us believe it's a question of gravity to build artificial worlds for mankind. He pretends he believes in freedom: more living space means more divergent evolution. – But everyone (except him) knows it: Already on Earth any divergence (from U.S. interests) will be punished with sanctions or killer drones. – In space divergence will not happen at all.
As I've shown above, there will be no freedom for hypothetical worlds in space (naming it military bases would be more clear) beyond "evolution" of laboratory rats and underlings – there can't be something else than total control. A civilization in space will be anything but civil.
My verdict on Anders Sandberg's view: The future of mankind is not a question of gravity of an artificial world (or of billions of other technical parameters Sandberg calls "within relatively easy reach") but a question of perfect lying about this future.
 More perverted hopes for exoplanets:
- 2015-07 .. S. Hawking and Yuri Milner announce $100M to seek ET
- 2015-07 .. Discussion on Kepler-452b
- 2015-12 .. Centauri Dreams by Paul Gilster (site provides a huge blogroll)
- 2015-12 .. Vote in the NameExoWorlds contest
(In general naming is celebrated for the loved ones. - This emotional approach to exoplanets is intended. They even call some exoplanets "worlds", "super-Earth" and "habitable". Blinded people get comforted by an irrational hope and get brainwashed concerning the real future of humanity.)
- 2016-04 .. S. Hawking and Yuri Milner back interstellar travel project
(S. Hawking knows full well what the real questions of the project are:
- How can the elite escape from dying planet Earth and from dying mankind?
- How can people be deceived as long as possible about their real future?
Of course the suggested tiny spacecrafts can't explore "Earth-like" planets at all. It's simply stalling tactics.)
- 2016-08 .. Planet is believed to be Earth-like and orbits at a distance to Proxima Centauri .. (ESO.org)
denim_chicken commented: "Keep dreaming. If we cannot even understand or live in accordance with the life support systems of what is literally the most habitable and human-friendly planet in the Universe then there's no way in hell that we will be able to successfully colonize a lifeless planet. Stop thinking about outer space when we are in the middle of an anthropogenic mass extinction here on planet Earth."
- 2017-03 .. Matt Williams' website Universe Today propagates massively delusions of terraforming Mars, "terraforming" Earth and reaching exoplanets.
But since it's even on Earth impossible to undo carbon dioxide enrichment in the atmosphere, to undo the ocean's acidification and global warming, all the terraforming and colonization fantasies are simply brainwash.
- 2017-05 .. "Visions of the Future" - advert posters .. exoplanets as imaginative travel destinations by NASA/JPL.
As advertisement for NASA it's a funny idea and the posters are beautiful. But to impart the illusion to the people they could reach another earth (and therefore ruin this one) is a crime.
- 2018-02 .. "Habitability" of TRAPPIST-1. - Probably the biggest demagogue of all in this respect is eso.org
- 2018-03 .. "Lost in Space" series (Netflix) - The essence of the trailer: "When this world can no longer serve our purpose - another planet, another colony, another chance." – That is not just 'dream factory' and business. It is brainwashing covering up the consequences of US capitalism for planet Earth. The disaster of the ecosystem Earth is not "from above" as the trailer suggests.
- 2018-07 .. Der Exodus der Geldmenschen / Marsianische Fieberfatasien. - Tomasz Konicz analyses (in German) the topic quite similar from a economics point of view. – Follow-up: Klima für Extremismus
- 2018-10 .. Jeff Bezos predicts we'll have 1 trillion humans in the solar system The most capable tech manager in the world is in social sciences completely mindless.
 Added 2016-03: "No reduction of biodiversity at all." – To what extent this is impossible tells Harvard professor Edward O. Wilson in his book Half-Earth (quite late, if you ask me). Except Antarctica and some remaining areas of virgin forest man has occupied complete earth. Wilson comes to the conclusion to safe planet earth humans would have to withdraw from 50 percent of it. — The figure comes purely from statistics of biodiversity and extinction on Earth. It comes not from the world we live in: war of economies and battle for global resources. So, "50 percent" is wishful thinking – in the real world at best freezing the status quo (no more deforestation) is achievable.
Wilson speaks of awareness of the deadly damage that is essential to prevent the collapse of the ecosystem Earth and he speaks of decisions humanity has only a short time to make. – Well, in my view, awareness doesn't matter at all in this case because there is no decision to make (whether the principle "eat or be eaten" is valid or not). — By the way, it's the same thing with Donna Haraway's philosophical speculations about 'benevolent survivors'. In fact the survivors, the elite of unscrupulousness, will not be benevolent.
The North Americans (in particular professors) are trapped in the delusion everything is a question of technology, of goodwill, of power, of democratic decisions. — Decision. What decision??.. It's absurd.
"Fifty percent" is the exemplary idea of a solution of someone who doesn't know what's going on. – Or what is it: fifty percent of the oceans should be protected from being damaged by warming, plastic waste, ship pollution, plutonium and acid?
There is no protection from capitalism. "Half-Earth" is nonsense.
Or what is it: to tell the U.S. Navy to leave Hawaii on behalf of conservation of biodiversity (that's not half the US but at least 0.5 percent)? Absurd.
The hidden elite that rules not only the US, that preaches the law of the jungle (the free market), that plans global dominance and (in the distant future) their exodus from Earth has no interest in humanity, biodiversity and Half-Earth philosophy.
Doesn't Wilson know what the purpose of U.S. military power is? What the sentence means "We defend American interests wherever they are threatened"? Of course he knows and he does his best to obfuscate, it is about exploitation of the whole world and NOT of half the world (– otherwise e.g. they wouldn't go after Russia so aggressively).
Well, a Harvard professor can't be against the US constitution. Edward O. Wilson is payed for benevolent pseudoscience, for spreading illusionary ideas, for distracting his students from evidence what the nature of US capitalism is.
Half-Earth's wishful thinking pretends to offer solutions. But it is feigned activity to play out time for the hidden preparations of the archenemy of mankind.
• Discussion on Wilson's Half-Earth at aeon
• Discussion on Wilson's Half-Earth at Hacker News
• Hacker News Discussion on biodiversity .. 2016-07
• In Germany in many regions the amount of insects decreased by 80 percent .. 2017-06
• WWF Living Planet Report 2018
Animal populations have declined by 60% on average since 1970. — The three biggest mass extinctions of prehistoric times needed thousands if not hundreds of thousands of years to happen. So, no math is needed to know today's mass extinction is the biggest, fastest and deadliest in the history of the planet. Much worse than what carried off the dinosaurs.
 Added 2018-06-01: In his study Evolution of Exo-Civilizations Adam Frank, professor of astrophysics at the University of Rochester, comes to the same conclusion: planets' ecosystems are collapsing when a tech civilisation evolves. The scientists used computer simulations and methods from dynamical systems theory for their model calculations. – The outcome is a confirmation of some statements I made in this article. But at two points Adam Frank tries to deceive us:
- Capabilities of man to master the social process of evolution
- The game that shapes our society is called competition, or more precisely fight. Or let's name it frankly: it is war.
No one (in particular no society of any country) has the chance to say 'I do not play the game any longer on behalf of survival of mankind'. That one would simply lose. — There is no "decision-making by the species" before it's too late (before it is forced by misery).
- Ethical integrity of man is limited. A human being is basically good and benevolent and a sane adult will wish humanity has an unlimited future. – But clearly a sane adult will also say: better no future than a future "under this certain rule". (Try to preserve East Jerusalem as the Palestine capital and you will see.)
So, the own internal dynamics of evolution are not governable (as A. Frank tries to tell us) – in both respect: not as a practical social process (the point before) and not in its spiritual foundation. — "Equilibrium in the planet-civilization interaction" is not about technology. (Try to shrink the Chinese and Indians to 50 million each and you will see it's not about technology.)
- The game that shapes our society is called competition, or more precisely fight. Or let's name it frankly: it is war.
- Commonness of technological civilizations in the universe
- "More than 10 billion trillion planets likely exist in the cosmos." – This statement is very likely wrong. The number of planets in a limitless universe is limitless. But the point is it's irrelevant. The commonness of civilizations is in other galaxies not much different from that in the Milky Way Galaxy. Other galaxies are of no account for this question. The 100 billion planets of the Milky Way are.
- I trust the simulation's outcome that collapse of a civilization is likely. But I disagree that this is the answer to the Fermi Paradox. All coincidences that are needed to let a civilization evolve are together just extremely rare. We are simply the first. — Bias is not nature's part but the part of the lucky winner ('Why Earth of all planets?').
Adam Frank's study spreads the word for the adequate approach to the problem and it clarifies for the topic of this article: It makes absolutely no sense to do space travel to exoplanets when the time span until a planet is ruined by man is shorter than the time span that is needed to get to the planet.
As long as "transhumans" havn't learned to live on Earth for—let's say 1000 years—without producing remaining CO2 emissions, without contamination and waste landfill it is sham to look for other habitable planets.
But the transhumans will say rather: The easy solution is to exploit and ruin Earth, to make off and to minimise future populations on exoplanets: "Let us be a few, let us be gods". – In fact they are heisters of the human heritage.
These bastards shouldn't get away with it.
(That is my answer to Fermi – in case grassroots democracy is common in the universe.)
 Added 2018-06-20: Abraham Loeb, chair of the astronomy department at Harvard University, talks in his paper Securing fuel for our frigid cosmic future (2018, PDF) about the so-called cosmic winter. He thinks it would feel empty and sad when after 100 billion years all galaxies (except Milky Way and Andromeda) have disappeared beyond the particle horizon and in the galaxy all stars of the size of the sun (or bigger) have died. Loeb would prefer his descendants resettle to the Virgo cluster which local gravity binds its galaxies against scaling of space.
— Well, in 100 thousand years (that is 1 millionth of the timespan Loeb contemplates) every thought that ever can be thought will have been thought. Every possible world that can be imagined will have been simulated in all details.
I doubt Loeb understands what the famous C-Beams Speech is about. It is not about managing to have another 100 thousand years to go through it again. It is about being human and preserving life here and now.
My verdict: Abraham Loeb has no right to use the words "we", "us" and "humanity" in his speculative (characteristically jewish) paper. It is absurd to do so - it will not be humanity then. Contemporary fiction stories are (compared to this arXiv paper) for sure more human and truthful: "Huddling in the pale glow of the star rejuvenated with my remaining fuel, we share the last shreds of our memories. Anything that could break had long ago been broken." (Cosmic Spring by Ken Liu, 2018)
But what intention do Loeb's scientific effusions have? "Once settled in a cluster, a civilization could hop from one star to another and harvest their energy output just like a butterfly hovering over flowers in a hunt for their nectar." – They are demagogy written to obfuscate that the kind of "scientist" he represents is ruining planet Earth and humanity within the present decades.
➡️ Timeline of the far future (wikipedia.org)