Could we survive a Cretaceous-Paleogene-like extinction event?

Just something that I was wondering about.

Suppose that tomorrow, a catastrophe of the same level of the Createous-Paleogene extinction event, that is,

1. One of more powerful asteroid strikes and/or eruptions, raising a huge amount of ash and dust and severely disrupting the climate;
2. Reduced sunlight and photosynthesis, with 50%+ of plant life becoming extinct and the rest underperforming for about ten years at least;
3. Mass extinctions of animals, in particular sea life and insects, severely damaging the ecosystem's stability.

If this happens (assume that we have no space colonies or whatever at the moment), could we survive as a species? And if yes, which steps would we take in order to maximize our chances?

edited 10th Jul '12 4:33:25 AM by Carciofus

But they seem to know where they are going, the ones who walk away from Omelas.

We can't really predict what specific effects such an event would have, but we can probably deduce some general trends regarding the survival of various life forms.

The last time this happened, the damage was most severe on sea life and the most dominant and massive lifeforms on land. So out of today's land mammals, one could perhaps expect the largest herbivores and most predators to suffer the most. We would probably see the end of lions, wolves, bears, elephants, kangaroos, moose, and so on. The last time this happened, animals that somewhat resemble rodents and shrews survived, so we could perhaps expect small herbivores and omnivores to survive.

One interesting question is: since all life that currently exists on Earth has its roots in the collection of species that survived last time, and since their survival was probably due to some inherent features of the species in question (instead of blind chance, which would only be plausible if the mass extinction event actually was a single event instead of a period of difficult conditions,) have the current species inherited those features, or have they been lost as life has diversified?

Human survival would largely depend on the transitions that our environments would undergo. As long as some life survives, we'll probably have food; but will we have enough? How many percent of current human population would perish in the first decades after this event? What would happen to the climate?

I think it is clear that a majority of today's mankind would die, as we are already living on the edge regarding our ability to produce food. Clean water is even more scarce, and while the demand for water would of course ease due to the death of perhaps billions, this catastrophic event might very well ruin much of the water reserves, thus offsetting the savings from mass death.

We know that mankind has, some 70 000 years ago, survived a bottleneck event, where the entire population of humans was reduced to something like 15 000. This is encouraging, because it tells us that mankind can survive such dramatic conditions. Then again, the hope that we may derive from the knowledge that we survived that bottleneck is surely shaken when we recall that the event that caused the crisis was the eruption of a supervolcano in Indonesia, an event much smaller than the kind of situation we're talking about in this thread.

Do we have better means of survival than we did 70 000 years ago? The answer surely has to be "yes," because we have civilisation, among other things. We think we are dependant on our lifestyle supported by agriculture, but if we are to survive a period of mass extinction, we'll have to learn the life of the hunter-gatherers again. We are probably smart enough (compared to 70 000 years ago, when our social life was probably not so developed that we would've reached the level of coordination and planning that we are capable of now) to compare favourably to our ancestors from that ancient time, even though they were likely to have been physically much stronger than us, even with some extent of malnutrition.

But even if we do manage to develop something like a hunter-gatherer tribal society, a question that I can't help thinking about is: what game would there be to hunt? Extinction events tend to target the largest species around, so that would devastate our selection of game to hunt. The K-T extinction event also killed a huge portion of sea life, so we might not have anything to fish or farm from the sea. If that is what would happen, I frankly don't see much of a way out for more than perhaps a couple of thousand humans.

edited 10th Jul '12 5:05:46 AM by BestOf

Quod gratis asseritur, gratis negatur.

Best Of, think of the stats. When Toba blew, we had barely made it out of Africa for long enough to lose an accent, let alone really annoy our neighbours. The population wasn't all that fantastic to start with before the deaths (possibly barely over 250,000, if even that), and, in global terms, was still very localised, and probably revolving around beach-culture at the time (well, that last is supposition, but likely). Hence why we got hit more than the cousins did, genetically.

Nothing fuels innovation quite like the burning idea that living as you did was suicide, so... let's try anything new, eh?

Now look at us. We're practically everywhere, and number well into the billions. Statistically alone, we have an odds-on chance to survive most disasters.

edited 10th Jul '12 5:47:20 AM by Euodiachloris

The easiest way to survive a global extinction event is to have another globe. We're inching towards that goal, albeit very slowly.

I think that humanity is too numerous and too clever to be wiped out by anything other than the complete eradication of multicellular life on Earth.

"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"

I agree that it's likely that we would survive a Cretaceous–Paleogene style extinction, providing there is no anoxic event involved, but AFAIK this didn't happen in the end-Cretaceous extinction - only the end-Permian one.

"For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled." - Richard Feynman

It's kind of funny (in a not very funny way) how these historical anoxic events all featured high levels of greenhouse warming as a major trigger...

"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"

It appears to use the present during the start of the Industrial Age as the beginning of those, and have to be four times as bad. So.... I think we're fine right now as far as that goes.

Look, as long as there's something to eat, we'll eat it. We might not like eating pigeons and rats, but if that's what's available after cows have died out, we will. As a whole the survivors will probably go back to small plot farming relatively quickly.

Well, I was noticing the part where a 3 degree Celsius global temperature increase would set the stage for a burnoff of most forests. That would contribute enough additional greenhouse gasses to set off a runaway cycle.

"It's Occam's Shuriken! If the answer is elusive, never rule out ninjas!"

If we have warning that it's going to happen, we can probably survive it.

Also, +1 on the point that this planet is a single point of failure for our species.

I'd like to point out that both the Jurassic and Cretaceous weren't exactly life-free zones, even while the oceans were... less than stellar for touristy holidays, and things on land tended to go up in smoke. It took a sodding great big meteor to really bite down, even with all that going on.

Heck... we're not exactly optimally adapted for Australia... And, it goes up in smoke fairly regularly, and is not, on paper, an easy place to live.

edited 10th Jul '12 12:13:27 PM by Euodiachloris

I think what we can take from that is that people will figure out a way to live just about anywhere because that happens to be where they are. And in a post apocalyptic world we wouldn't have the choice to pick up and move to greener pastures. Case in point; that one town in Australia where they apparently dug underground in order to beat the heat. Another case in point; the fact that anyone at all lives way up in the Arctic.

Some people just seem to settle well into extremes.

I'm probably being very biased in my Pro Humanity stance (for obvious reasons) but I think we have a decent shot at surviving the extinction event.

Since we have actually seriously contemplated nuking each other to radiated dust about 50 years or so ago, and perhaps even up to today. We have made more advanced discoveries and refined plans (even if our efforts are now redirected elsewhere) to survive that self inflicted extinction event.

The key element of course, would be time.

How much warning would we have? Could we take steps to minimize the problem before it gets here? Who will mobilize the quickest, greatest, most efficient force to face this problem?

The end result could be anything from a happy "Doomsday Averted by Heroes!" movie or a really crappy Post Appocalyptic world foccusing on how crappy the world is now.

Also the amount of warning does help. Something like global warming will hamper human existence efforts but I would expect that even while we'll act very stupid, do very stupid things and maybe even get a lot of humans killed over the decades, we'll continue to exist.

For something like an asteroid impact, supervolcano eruption and other totally unexpected events (like say a blast wave from a supernova) because we didn't have enough infrastructure set up for an early warning system, it's not likely that all humans die instantly. We'll lost a lot of infrastructure but even say a disease that wipes out 96% of humanity will leave 280 000 000 humans left, which is orders of magnitude more than cave man days, and a whole bunch of tech for us to use to rebuild. In fact such a horrible post-apocalypse world may have the curious silver lining that we'll get back much of our forests to suck up carbon, and we might not lose that many years to technological downtime allowing us to become more advanced with a smaller population footprint.

Of course, the only sure bet to survive anything that happens on Earth is to live on more than one planet in a self-sufficient manner.

How much warning are we talking about? If we have a month or so I think we could all manage pretty well. The world economy would essentially collapse (assuming this is a worldwide thing rather than something localized to a single continent) but to be honest I don't think that's a major tragedy in such a scenario. We kind of have bigger things to worry about.

The biggest concern I can see is there being so many people we burn through most of the resources that last through the apocalypse but as long as some people survive they should be able to carry on humanity in some fashion.

In event of an asteroid collision there is absolutely now way to save everybody. Some might bunker down. Maybe people up on the fringes of the artic can survive off the land for a while. I dunno.

Really, something like a meteor headed for Earth would cause widespread panic and rioting before it ever reached here, so it's highly likely many of us would be dead even before that.

There was just a movie about this, Seeking A Friend For The End Of The World.

Anyway, I doubt it. As the above poster said, we'd all go crazy before that anyway.

edited 10th Jul '12 9:11:29 PM by wuggles

Could we? easily. would we? depends on the amount of looting and civil war that accompanies large parts of the human population dying off.

basically, if we built a system of underground shelters, ALA Fallout, which were nuclear power and had farms using UV lights an such, we could survive as a species. however, theres no way in hell we'd save all 7 billion+ of us. we could easily save thousands, hundreds of thousands if government put a bit of foresight into it, and more if we had years to prepare and we put all-to-most of our resources into such a project.

I'm baaaaaaack

True but depending on where it hits and how much notice we have I think we could prevent it from wiping out too much of the human race. If it hits in, say, Africa then we've pretty much lost them, the Middle East, Southern Europe, and maybe parts of Asia but I think Australia and the Americas would be okay for a while.

Hundreds of thousands isn't a bad number. We've had fewer than that at numerous points in our history as a species. Provided a large part of them are located relatively close to each other and there's an adequate supply of resources they should be able to go on indefinitely after the major fallout from the asteroid occurs. Yeah modern society is pretty much screwed but something will be left over.

edited 10th Jul '12 9:14:58 PM by Kostya

Dammit wuggles, you stole what I was gonna say.

Insert witty and clever quip here. My page, as the database hates my handle.

I don't think that's true. I can't imagine a set of circumstances that would destroy civilization so thoroughly that we would revert to a hunter-gatherer society; anything bad enough to prevent us from farming would be bad enough to kill us off entirely. Plus, anything that would hit us that hard would probably kill off anything we could hunt and/or gather, as well.

But we're well beyond the point where we we could realistically regress back that far anyway. The average adult today knows incomparably more than the smartest people on the planet did even a few centuries ago — and knows it so thoroughly that they take it entirely for granted. If all technology more advanced than sharp rocks were to somehow magically disappear tomorrow, we wouldn't be building any microprocessors (or anything else that requires an advanced infrastructure) any time soon, but simple facts like "disease is caused by germs" (as opposed to spontaneous generation or miasma) would give us a huge leg up over our ancestors who had to make those discoveries for themselves. So even if we were somehow reduced to the technological level of a hunter-gatherer society without being driven extinct outright, we would rebound back to an advanced agrarian civilization in relatively short order.

edited 10th Jul '12 9:18:31 PM by NativeJovian

Really from Jupiter, but not an alien.

How does that mean we'd become farmers? If anything the average human nowadays would probably be better at hunting than they are at farming.

Also we'd know how to build a society but would we have the resources? Yeah people know about buildings and plumbing and such but how would we get the materials or the precision machinery to construct the parts for it? We'd likely build houses but I don't see them being any more advanced than log cabins for the first century or two.

edit: I just thought. Assuming libraries with books survive and people bother to retain the knowledge to read them we could probably use those to develop a pretty good society almost immediately following the event.

edited 10th Jul '12 9:20:46 PM by Kostya

Assuming people survive, Kostya, we'd have to re-learn skills like farming. And since a lot of people do things like gardening flowers and small vegetable gardens, it's not that unlikely that they'd try to do so in a post extinction event world. Farming is probably an easier skill to learn/re-learn/expand on than building houses, anyway.

People would probably also stick to small groups, at least until things like plumbing and road building and such got re-developed, which means we'd probably take a couple generations at least to build back up to cities as human societies.

After our theoretical magical technology-destroying event, people would become farmers because farming is simply a better method of getting food than hunting and gathering is. I mean, sure, in the short term there'd be a lot of hunting/gathering going on, because you need to eat while you're getting a crop in, but in the long term farming beats hunting/gathering all hollow. It's simply a more efficient method of getting the nutrition we need to survive.

We certainly wouldn't be able to sustain our current population without our current level of technology; there would be a population crash almost immediately, both from direct (ie, people stabbing each other over food) and indirect (ie, starvation and disease) causes. After the population stabilized at a sustainable number, though, I think we'd rebound fairly quickly for all the reasons I've already mentioned. It might take us a few hundred years to get back to where we started, but that'd still be fifty times faster than the first time around. (For the record, the neolithic revolution — the transition from hunter-gathering societies to agricultural societies — was around seven to ten thousand years ago.)

Of course, if records of humanity's collected knowledge survived in some form (whether it be in books or computers or whatever), then that rebound would be much, much faster. But even if we only retained what was in people's heads at the time of the disaster, I think we'd do pretty well for ourselves.

edited 10th Jul '12 9:37:55 PM by NativeJovian

Really from Jupiter, but not an alien.

Not really. Early agrarian societies has worse health and nutrition than hunter-gatherers. I'd agree, though, that farming is absolutely essential if we don't want more than 95% of people to die off.

I vowed, and so did you: Beyond this wall- we would make it through.