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we have important potentially civilization destroying or, in some models, extinction level problems coming at us in the relative short terms. That is to say that I don't think he means we need to fix every problem on earth before going to Mars, but that trying to set up Mars colonies or similar escapades while not dealing with climate change would be useless because whatever we built in that short term on Mars is going to need extensive support from something here.

on edit: fixed typo.

Could you elaborate on the extinction-level problems? I hear this a lot, but it's almost always nonspecific and hand-wavy. Do you mean the potential mass release of hydrogen sulfide into the atmosphere, or a runaway effect increasing CO2 levels to deadly amounts, or something else?

Probably no matter what happens, unless the cobalt bombs go off, a few million people will survive, here and there.

The most likely final outcome of full-flowered climate catastrophe is global thermonuclear war. Before that happens, we will probably have two billion people starve. After, another five billion. The ocean will cease to be a reliable source of protein, and whatever sea life survives acidification will be fished out at an increasingly frantic pace.

In the hydrogen sulfide upwell scenario, the survival of humanity in any quantity seems unlikely. I'm just a layman, hopefully experts can tell me why this won't happen:

https://en.wikipedia.org/wiki/Permian%E2%80%93Triassic_extin...

>The Permian–Triassic extinction event, also known as the End-Permian Extinction and colloquially as the Great Dying, formed the boundary between the Permian and Triassic geologic periods, as well as between the Paleozoic and Mesozoic eras, approximately 251.9 million years ago. It is the Earth's most severe known extinction event, with the extinction of 57% of biological families, 83% of genera, 81% of marine species and 70% of terrestrial vertebrate species.

>Possible causes supported by strong evidence appear to describe a sequence of catastrophes, each worse than the last: the Siberian Traps eruptions were bad enough alone, but because they occurred near coal beds and the continental shelf, they also triggered very large releases of carbon dioxide and methane. The resultant global warming may have caused perhaps the most severe anoxic event in the oceans' history: according to this theory, the oceans became so anoxic, anaerobic sulfur-reducing organisms dominated the chemistry of the oceans and caused massive emissions of toxic hydrogen sulfide.

According to this hypothesis which is well-supported by the archaeological evidence, it took Earth's atmosphere between hundreds of thousands to millions of years to return to conditions capable of supporting much life. That's a long time for biodomes, bunkers, and orbital stations not to break in irreparable ways.

We can get a sense of how bad that extinction event was by noting that all bony fish in the ocean are descended from freshwater species.

A sufficient number of humans for repopulation can survive for a very long time in underground caves powered by breeder reactors.

Mister President, we must not allow a Mineshaft Gap!

thank god we have all that set up then.

We don't know that nobody does. We don't even know that the US doesn't. Putin could have one, and China, Israel, England, and France seem likely. Japan and India are possible. North Korea? Iceland, if they could afford to dig one, wouldn't need the nuke. Peru might have inherited one from deep time. Egypt, likewise. Turkey has lots of underground cities already dug that mainly only need wiring.

I don't think anyone in power would enjoy living the remainder of their life underground in a bunker. So this is implausible as a scenario.

Mass murder will begin well before 7 billion starve. We can slash global emissions using weapons without affecting our lives too much. I’m surprised this isn’t discussed more.

“Our” lives? I assume you mean rich Westerners? If you’re getting bombed, it’s gonna affect your life quite a bit.

Yep. The ones with the weapons.

I mean China is one of the countries with weapons and probably the most likely place you would want to decrease emissions if you were in the West and didn't want to decrease your own. So there's no way that would go well.

Which includes Russia, China, India, Pakistan, Israel, and probably Iran and Japan soon. Any one country could reach for the nukes first, or any small group could attempt a Sum of All Fears scenario.

> Probably no matter what happens, unless the cobalt bombs go off, a few million people will survive, here and there.

Arguably that’d at least be a “human society extinction” event.

I find cities of less than about 5 million people uninteresting in terms of having enough of the entertainment and eating out options I enjoy.

A planet with a few million people scattered here and there would be incapable of much more than early industrial revolution technology I suspect. I can imagine people building steam engines, but making transistors is beyond that capability of pretty much everyone I know. Perhaps a few million people would get by scavenging electronics left behind by the 5 billion dead, but they’re not going to be running semiconductor fabs and buying new cpu or ram chips. And they’re not going to be mining rare elements and smelting alloys like modern metallurgy.

I’m not sure what small and distantly distributed bands/villages of humans trying to find habitable places with productively farmable land would look like, but it doesn’t sound fun to me…

I’m old, and _maybe_ I could justify my existence in post climate apocalypse society by being “that guy” who gets other people to carefully remove the wiring harness and everything plugged into it from every abandoned car they come across, and re purposing engine management and entertainment system components into useful computing devices and electrical gadgets, or perhaps by building carburettors and magneto ignition systems to make efi vehicles run on home grown biofuel. But I’d say I’m Rob ably way more likely be killed (and eaten?) as an old person with no useful contribution to the clan.

We can see what happens when a big civilization collapses by looking at the Amazonian tribes. Their ancestors were extremely sophisticated, but they forgot it all, except a few gems like making curare and ayahuasca, and detoxifying cassava.

Right, so as an old person, I should be brushing up my shaman credentials and ethnobotany knowledge…

I'm not really one of the people who believes in the extinction models (though no some people do), my thinking on that matter though is, lots of species will probably go extinct from this, if industrial level civilization cannot be maintained during climate change crisis then there is no specific reason why the human species would not be one of the species going extinct, we're smart, but without the delicate and hard to maintain infrastructure of technology it seems unlikely we would be able to leverage that intelligence to keep ourselves alive.

My personal fear though is more the model of large parts of earth's surface unlivable by humans, humanity down to a few million living near the poles.

Although both of the two you mention of course also strike me as potential catastrophic scenarios.

The acidification of the oceans could easily kill plankton and crustaceans, destroying the food chain and leading to a mass extinction event.

Scientific paper on ocean acidification, which takes the reader through the chemistry:

https://co2coalition.org/wp-content/uploads/2021/11/2015-Coh...

It states in summary that:

"doubling atmospheric CO2 from the current level of 400 ppm to 800 ppm only decreases the pH of ocean water from about 8.2 to 7.9. This is well within the day-night fluctuations that already occur because of photosynthesis by plankton"

"doubling atmospheric CO2 from the current level of 400 ppm to 800 ppm only decreases the carbonate-ion concentration, [CO2−3], by about 30%. Ocean surface waters are already supersaturated by several hundred per cent for formation of CaCO3 crystals from Ca2+ and CO2−3. So scare stories about dissolving carbonate shells are nonsense."

"Over most of the Phanerozoic, the past 550 million years, CO2 concentrations in the atmosphere have been measured in thousands of parts per million, and life flourished in both the oceans and on land. This is hardly surprising, given the relative insensitivity of ocean pH to large changes in CO2 concentrations that we have discussed above, and given the fact that the pH changes that do occur are small compared to the natural variations of ocean pH in space and time"

"This minimalist discussion already shows how hard it is to scare informed people with ocean acidification, but, alas, many people are not informed."

If you or anyone else thinks this paper's calculations are wrong, then that would be interesting to learn why.

The "past 550 million years" includes the Permian-Triassic Extinction, or Great Dying, of 251 million years ago. Do they refer to the million-year death zone after this event as a period when "[CO2 was] measured in thousands of parts per million"? Seems like an incomplete analysis.

Wikipedia claims, "[the] trigger for these mass extinctions appears to be a warming of the ocean caused by a rise of carbon dioxide levels to about 1000 parts per million":

https://en.wikipedia.org/wiki/Anoxic_event#Atmospheric_effec...

Here's the Scientific American article they cited:

https://www.scientificamerican.com/article/impact-from-the-d...

Could we not do both? Using the US as an example our space budget is peanuts compared to the defense budget. I know the defense contractors will get mad they cannot fleece taxpayers as much if we adjusted, but oh well.

Hey, don’t take civilian space contractors lightly. They can fleece taxpayers just as well or better than defense contractors. 2022 is the year of Linux on the SLS.

> trying to set up Mars colonies or similar escapades while not dealing with climate change

Would you be okay with the effort to go to Mars if the main person advocating for it were also simultaneously personally doing more than anyone else alive to reduce the human consumption of fossil fuels on Earth?

sure, however what I said contained the following:

>That is to say that I don't think he means we need to fix every problem

in short, my post was really describing what I think Robinson was getting at and I am not really wedded to the argument that we shouldn't do both at the same time, especially as the stuff we do to make one planet habitable might give spark to scientific/technological advancement that could help save the one we have.

> always going to be something threatening us even if it's mainly ourselves

It's always "ourselves". We as a race are our primary enemy and your desire not to see the problems we create for ourselves here and now makes you exactly the reason we will suffer. I used to fear human extinction, now I'm resigned to it.

> It's much easier to be an "escapist" by dabbling in distractions on earth than it is by building rockets or working on the science to make life possible on Mars!

Yep, I'm resigned to it.

Sorry, we won't get extinction. At least 0.1% will come through whatever happens, and, like the Amazonians after the pandemics, forget all we had and did.

If we face an anoxic ocean event, this simply isn't true. Such an event could leads to the upwelling and release of huge quantities of hydrogen sulfide. Diffused throughout the Earth's atmosphere this would kill nearly all life, and remain present in lethal concentrations for hundreds of thousands to millions of years judging by the fossil record from the Permian-Triassic extinction. That's a long time to rely on artificial life support systems.

https://en.wikipedia.org/wiki/Anoxic_event#Atmospheric_effec...

Probably some thousands could still survive, then. It would be hard to know why, but people have ways of finding reasons.

the idea of going to mars is basic science, and basic science has yielded all sorts of useful discoveries for the human race.

but it is also hard to ignore the fact that it seems circular to turn the earth into something that looks like mars in the pursuit of turning mars into something that looks like earth.

so yes, doing basic science is good. but let's be clear that it's not a real plan and that the real problems at home are not only easier, but also far more pressing.

Except, going to Mars is not, in fact, science. Sending probe after probe is science, although it is getting pretty reflexive now, as very little remains to be learned from them.

yeah, maybe you're right. it does, however, seem to share something with basic science: it's an endeavor with no immediate or obvious value, yet expands the frontiers of knowledge and know-how for the species as a whole.

Humans can do much better science than a probe.

For the cost of sending and sustaining people there, probes could do overwhelmingly more than they have done.

But there is little science of value left to do on Mars. They could have sent a microscope on any of the probes lofted, but chose against it.

Nevermind that even if we turned Earth into a glorious green utopia, eventually a big enough rock is going to come along and boop us and kill everyone and everything.

https://en.wikipedia.org/wiki/Tunguska_event

https://en.wikipedia.org/wiki/Chicxulub_crater

https://en.wikipedia.org/wiki/Chelyabinsk_meteor

https://en.wikipedia.org/wiki/Yilan_crater

https://en.wikipedia.org/wiki/Karakul_(Tajikistan)

https://en.wikipedia.org/wiki/List_of_impact_craters_on_Eart...

Maybe we can deflect it. Maybe we can’t.

Right now we have no offsite backups. That should terrify everyone who cares in the slightest about human culture.

It is unlikely any of the planets in the solar system could sustain humanity or life if the Earth is lost in the next few centuries. Thousands, at most, would live on the planet. We've always had an ecosystem to rely on, and even a severely damaged one would be more survivable than the cold wastes of Mars.

Well then we’d better hurry and get started building colonies now, as the destruction of humanity on Earth might be in a year or a kiloyear or a megayear—we simply don’t know.

Don’t wait for the drive to start clicking to make backups.

You are welcome to build a refuge at the South Pole. It will be an overwhelmingly more livable environment than can be constructed on other bodies. Or out in the middle of the Kalahari Desert, or in the center of Australia, likewise.

Southern hemisphere is recommended, anyway, as probably few nukes will target there; maybe none!

The South Pole is also at risk from sufficiently large impact events elsewhere on Earth.

You'll also note that humans do in fact have a permanent settlement there.

We do not. We have an outpost. Literally no one actually resides there; everyone there is a temporary visitor, with a home elsewhere. It is 100% dependent on imports of every single thing excepting only air and water.

Moot point. Not self sustainable.

Fuck offsite backups when our disks are failing.

If disks are failing and floodwaters are rising, I absolutely hope I have offsite backups!

The need to actually have that offsite backup being online makes them rather unlikely. Like setting up your offsite in middle of desert and trying to make parts there yourself. Fun times...

Presently it does not appear that the current cataclysms predicted for Earth in the short term (500 years) will result in destruction of the biosphere or even human extinction.

Early humans and their ancestors have experienced two major population bottlenecks in the past. We may well see a third relatively shortly, but that is very different from extinction.

You're using a linear model for exponential processes.

Which processes? When, why, and how will they become exponential?