You don’t need the “other”, there: Humans are far from being able to survive in every environment on the planet. In fact, most organisms can survive in a significantly greater range of environments than we can. We’re not very good at surviving in other environments; we’re just good at bringing the one environment we can survive in with us.
We are also the only species capable of using technology to deal with those things. We can use sanitation and hygiene to keep viruses and infections at bay, and we can use shelter and clothing to deal with weather variations. As a result humans live in areas that are 110F and areas that are -80F. And by taking a few affordable precautions a person can avoid virtually every serious microbe infection.
So no I don’t think our species can die out under any realistic scenario any time soon. Even if 99.9% of people die, that leaves 7 million people. But if those 7 million people have access to a library of sorts, there is no need to reinvent the wheel and they will still have information about medicine and agriculture which they can use to repopulate.
Humans, yes, but we’re talking about humanity as a whole.
Six of one, half a dozen of the other. If we can build igloos and live in the Arctic, how is that not surviving in the Arctic? We build igloos just like ants build nests or beavers build dams, except for the fact that when we migrate to a different environment, we evolve technology allowing us to survive there, too. Human knowledge is as much part of humanity as human DNA.
No, certainly we aren’t too resilient to die out. Eventually we will die out, after all, since that is the fate of all living things on cosmic scales. I’d say that humans have the potential to continue past the extinction of the planet, if we are wise enough to use the knowledge and actually do something about it…but given a big enough disaster we can certainly be wiped out, especially if we simply stay on this planet for the duration. The planet (or, perhaps the universe) will kill us off eventually, with a probability of 1, assuming we don’t manage to do it ourselves.
-XT
It rather makes a difference which 7 million survive - who are they, what’s their distribution, and do they have a way to scrape together food for the next two weeks?
Which really brings it back to ‘what killed us’? Giant meteor strikes are fun because they wreck the global food supply; all the education and technology in the world isn’t going to help you once the supermarket shelves are bare and the crops are dying. Extermination plagues are fun because they functionally would target populated areas; your survivors would be nowhere near a library if it has a 100% kill rate for the infected, and if there are scattered survivors most won’t be able to cobble together a continuous food source before the canned food runs out.
I suppose you’re going to tell me that those circumstances are ‘unrealistic’ - I’d disagree, especially about the meteor. They’re rare, sure, but it would hardly be the first time. Viruses are less prescedented but certainly possible. You have to get to alien invasions and zombie uprisings before ‘unrealistic’ stops being a misnomer, really. (Global Thermonuclear War is on the borderline, because while we could nuke the world, in practical terms there are large inhabited areas that would be ignored.)
A few very specialised groups. Certainly nothing that would have led to even one human death.
WTF?
By cockroaches I assume you mean the common pest species. Far form being global, they are restricted to the subtropics and tropics. Outside that region they can only exist in human constructed habitats.
Ditto for rats. Over the vats majority of the world they are completely unable to exist outside human habitats.
Tapeworms have one of the most restricted habitat requirements on the planet. They can only live within the intestinal tract of their host species.
Not exactly examples of animals that can thrive in every environment on the planet.
I know (although it would have meant hardcore poverty for lots of fruit & veg farmers, and a great reduction in our variety of food intake.) But that wasn’t the point - the point was how dependent we still are on other species - insects, yeast, bacteria. Hell, life would be unpleasant and probably a lot shorter for many just without our intestinal ecosystem.
If humans can, so can they. That was kind of my (facetious, I know) point, that if humans survive, we won’t be alone. Hell, we can’t even stop life from contaminating our spacecraft.
I doubt there is a plague that could kill everyone. There are always going to be people who are resistant to various diseases. The point about science is that it makes it far easier to avoid plagues. The black plague killed about 30-50% of europe, but the rest survived. Evenso, had they understood germ theory the deaths would’ve been minimal. Even if there was a virus that killed 100% of people who contacted it (which is unlikely) there are going to be people who take precautions to avoid catching it and are not affected because of it.
You don’t technically need a ‘library’ since most are filled with movies and fiction books anyway. Library was meant to imply access to textbooks and other non-fiction documents so people have info on how to rebuild medicine and agriculture after a collapse and we do not sink into the dark ages.
I don’t know how people would survive a meteor. If they could live underground and have enough food to ride things out for a while, it would be possible. The last time a meteor hit it killed most land based life, but much aquatic and underground life survived. So if people could hunt and eat that until the surface was livable again it would be possible.
You’re presuming (in both examples here) that people get enough warning to do something about it, like in that movie 2012. Which is nicely optomistic but the question is whether it would be possible to wipe out humanity. Which means we’re looking at worst-case scenarios - including with regard to readiness. Is it possible that humanity could be caught flatfooted and unaware by a virus or a meteor, at least until it was too late? Yes, yes it is. So yeah.
The only thing that could kill us off at this point is a MASSIVE asteroid or comet strike or other huge cosmic event. That’s really it. There is no virus or bacteria that could ever come close, in any scenario, to wiping out humanity. Nuclear war couldn’t come close to doing it. And ice age couldn’t do it. Nothing really could aside from something that literally destroyed every square inch of land in one shot or bathed the entire earth in lethal levels of radiation. There’s enough food stores on this planet that if humans weren’t literally wiped out in one, huge, fell swoop isolated, small groups would survive even if the land wasn’t arable for years.
I disagree. What kills of many species (IMHO) is a combination of events and effects that first weaken them and then something else that finishes them off. So, we could have something like a really nasty pandemic that killed or weakened a significant percentage of the worlds population, then a climate change effect that further stressed it, and then some other event that normally we’d survive but that could finish us off given the weakened state of the species at that point.
In general I don’t think that it’s just one thing that kills off a species, but a series of smaller blows that weaken it and then a final event that seals (or passenger pigeons, perhaps) it’s doom.
-XT
I think we could handle a series of smaller blows, unless they were coming so closely one after the other that it was basically a single perfect storm of disasters. One think you can say about humanity is that we’re pretty good at recovering pretty quick from minor and even medium-sized problems, even when they come one after the other, as long as we get sufficient time to deal with each in turn. So naw, pandemic or asteroid strike it is.
That said, I dispute that one could not construct a virus that could kill humanity - the trick would be a long gestation/contigation time coupled with a near-perfect fatality rate. And -
If people can’t get to the food stores, it won’t make any difference, the same way it goes for the libraries. This is why I like to hedge my bets with both a pandemic and a meteor; the pandemic wipes out everyone remotely near civilization/libraries/food stores and shipping outlets, and the meteor wipes out the isolated leftovers via ending farming.
Though a good point was made about the fish surviving a meteor - better have that pandemic (or another one) kill all the fish too, just to make triple-sure. 
No. The population of Madagascar survives in this hypothesis.
That would depend on where I drop the meteor, now wouldn’t it?
Admittedly, there’s a limit to the number of places I can drop rocks on at once, which is why I’ve recently added the plague of the fish too.
I don’t think so. There is no pandemic that is going to spread across the world and wipe out significant numbers of people in developed countries today. And climate change couldn’t come close to wiping us out either. It never has and never will unless you’re talking some extreme ‘snowball earth’ scenario. And grand climatic change, even an extreme one, will happen slow enough that people will adapt.
On a side note, I can’t see how anyone could argue that we aren’t BY FAR the most resilient land species on the planet. In less than 100,000 years we (a single species mind you) has come to occupy every land environment on the planet. We can eat almost anything, provide shelter for ourselves, comprehend why said disaster is taking place and what the best course to take would be. You can’t compare any past extinction event to us. Nothing had our brains.
Note that I’m not saying our numbers couldn’t massively be reduced but, as has been stated, even 99.9% of us wiped out (which would never happen without a huge asteroid strike or similar) leaves 7 million people which is a higher population of humans than existed for most of our time on this planet as homo sapien.
I would still state the only thing that could wipe us out totally is something that obliterates the surface of the planet entirely in a scorching, incinerating blaze.
Again, I am saying multiple things, not one. So, perhaps a particularly virulent version of the flu virus causing 30-40% mortality, climate change that stresses agriculture, especially in the current bread basket regions followed by, say, a massive eruption in Yellowstone. I could see that series of events (plus some nasty wars and other stresses) taking the human species down to dangerously low levels. If you followed that with one more bit of bad luck then that could be all she wrote, and without having the entire surface of the world slagged.
If you are looking for a one shot kill to humanity then I think something like the Siberian Traps/Permian–Triassic extinction event would do the trick nicely. A Chicxulub scale impact would probably also do the trick, or at least so weaken humanity that a smaller subsequent event could take us down as well.
-XT
There is no currently known to exist pandemic that could do it. (If there were, we wouldn’t be having this discussion.) I maintain that the Iocaine Powder virus that’s transmitted by air, water, and physical contact, which remains completely inert for one month while spreading to everyone you get near and then dropping you stone cold dead on day 31, that would kill all humanity. Even Madagascar, unless nobody travels to there for the two weeks prior.
We can eat almost anything?
And until we outlast the dinosaurs, alligators, sharks, and cockroaches, they still win, from the very solid argument of practical fact.
We’re a lot flabbier nowadays - and I still maintain it matters rather a lot which 7 million people make the cut, and where they are. Heck, we could wipe out humanity by only killing half of it - the women. Or just pick 7 million people none of whom are near a sufficiently large stock of food.
Nope - though that would do it too of course. Also alien invasion or Final Judgement would do nicely.
The problem with the “food stores will sustain a small number through the crisis” argument is that there’s going to be 6 billion people all fighting over the same food stores, even as they’re dying of whatever the crisis is. Most of the stored food is going to be consumed by people who will die later of starvation. If we could triage the stored food and let some people starve to death right away then the picked survivors could last for generations on cans of lima beans and ensure. But it won’t work like that, by the time it becomes clear that mass starvation is inevitable it will be incredibly difficult to collect the food. It won’t be possible to buy the stuff, you’d have to create armed death squads to collect food at gunpoint. And pretty soon the squads are going to fighting each other, as it becomes clear that there won’t be enough food for all the grunts to survive.
There could be a few hidden sanctuaries with enough food to survive through the crisis decades, but how many survivors will emerge? A few thousand? How many babies will be born during those decades? If population levels get low enough any random problem means the extinction of that local population, and how many population pockets will be left?
How long does it take for people to realize a microbial infection is floating around? I believe even with government censorship of the SARS virus in China, people still learned about it via cell phones. In between cell phones, newspapers, the internet, word of mouth and television tons of people would know a killer virus was loose before it got to them.
If a major virus broke out it would be well known within a few hours of people dying en masse. That is how long it takes for news of a major natural disaster to become known all over the world (a couple of hours, or more aptly a couple of minutes). And there really is no virus that can kill 100% of people who contact it. And there will always be people who avoid being infected.
I see no reason to believe a virus could kill all 6.8 billion people on all the continents of earth. Viruses affect individuals differently, and they still have to pass through populations. If it started in Indonesia, by the time it got to Alaska the people would be ready for it.
good luck with that