Could humanity survive an asteroid strike?

[FireNexus]

Let's say an asteroid or comet impact like the one that killed the dinosaurs occurs in the near future. How likely is it that humanity (even only in small pockets spread widely) survives as a species if:

1. We have time to mitigate the impact. Building bunkers, storing seeds and supplies, etc.

2. The impact hits us totally unawares, such that any measures taken to mitigate the damage cannot be done until after the shit hits the fan?

I'm just curious. My thinkin is that humans are widely-spread generalists with large food and supply reserves that might carry us through to when the dust settles. We're also very adaptable and able to survive in extreme conditions. I can't imagine anything being able to wipe out all of us in a short enough time period to drive our extinction. I'd be comfortable betting as many as 95% die, just not everyone. I expect us or our descendants to basically be on Earth as long as it can support animals our size.

What does SDN think?

[Ziggy Stardust]

It's worth pointing out that the Cretaceous-Paleogene extinction "event" (i.e. the one that killed the dinosaurs) probably lasted a couple of thousand years. Though there is a lot of debate on its duration, to be fair. But it's highly unlikely that it happened over the course of any single individual organism's lifetime. The Chicxulub impact caused massive destruction, but also triggered a series of environmental shifts that made it difficult for the surviving species to continue propagating. After a few thousand years, those organisms that had been best adapted to a climate permanently altered by the impact finally died out, replaced by the ones that were able to more readily adapt to the new climate regime.

This is all to say that I think humans have both the flexibility and the ingenuity to survive a massively altered environment. The extent of this survival depends in part on how horrible the meteor's impact is and where it impacts in the first place. But the destruction would have to be pretty monumental - something that permanently alters the chemistry of the atmosphere, for example - to completely wipe us out. There are enough humans already surviving in far-flung, remote, and resource-poor areas of the world that it doesn't seem far-fetched for survivors to do so under most dinosaur-level extinction events.

[jwl]

I think really the most dangerous part of an event like that is that the resulting limited resources could trigger a huge set of global wars, and it is these wars that might wipe us out. On its own, while the human population would reduce, as a species we could survive something like the KT event.

[Zwinmar]

Could humans survive? certainly, however, the countries, cultures and nationalities are a different situation. It may regress civilization back to the bronze age or even stone, but humans in some form will be around.

[Simon_Jester]

Iron Age seems fairly likely. There will be so much salvageable metal around in workable form that the art of working it is unlikely to be lost, and iron is much more common than bronze anyway.

That said, in some post-apocalyptic scenarios you may well see Neolithic levels of social organization coupled with crude ironworking, so the point is well taken...

[Broomstick]

I find it hard to imagine an event exterminating the human race unless it obliterates pretty much all life on land. We're just too damn numerous and adaptable..

[GrandMasterTerwynn]

Let's say an asteroid or comet impact like the one that killed the dinosaurs occurs in the near future. How likely is it that humanity (even only in small pockets spread widely) survives as a species if:

1. We have time to mitigate the impact. Building bunkers, storing seeds and supplies, etc.

2. The impact hits us totally unawares, such that any measures taken to mitigate the damage cannot be done until after the shit hits the fan?

The Chicxulub event briefly heated the atmosphere to the point where forests caught fire across the planet. Cities burn. Farmland burns. Industry burns. On the coasts, quite a few cities simply cease to exist, owing to the enormous megatsunamis that an impact of that scale would kick up. The dust pall thrown up essentially shuts down agriculture for the next decade. Besides that, all major ecosystems and food webs that can support human beings collapse. The survivors of the initial impact and global firestorm likely inadvertently destroy any pre-impact preparations fighting over the last scraps of food. Civilization collapses completely and human beings are fragmented into small, isolated, pockets of population barely clinging to existence. Worse, the extra CO2 injected into the atmosphere, along with the sun blocking aerosols will wreak absolute havoc on the planetary climate; making stable, dependable, agriculture impossible for generations. The small, isolated, pockets of humanity live a hunter-gatherer's existence. Being large, efficient, predators; most follow the few remaining large land-based herbivores into extinction.

Basically, everybody dies. In the first scenario, everybody dies slightly later than they do in the second scenario. The only way to mitigate the impact of something this big is to make sure it doesn't actually land in the first place.

[Broomstick]

OK, but the Chixalub event obviously did not roast the entire planet because large animal life existed afterwards.

The thing is, humans are so clever, so adept with tools, so adaptable, and so widespread I just don't see us being wiped out by such an hit. Severely reduced in number, yes, but you only need a few thousand to (eventually) rebuild the population.

Humans would be able to figure out how to utilize their remaining resources to survive. Not everyone, of course, but some groups would come up with workable solutions to problems.

We use tools. Whether that's sturdy shelters of some sort, clothing to adapt to an environment, food preservation, or many other things it gives us an enormous advantage over animals.

Human beings can drastically alter their behavior to survive in various environment, from what food we eat, what sort of shelter we build, to even altering our mating habits.

Finally, because we are so damn widespread, groups are going to survive all over, whether it's some sort of outpost in Madagascar, or on the Tibetan plateau, or even an Antarctic colony (we have people year round down there, in several locations. Granted a Chixalub II is likely to leave them without resupply, the only people sent down there are healthy, able-bodied, and smart. They could hang on for a number of years then set out to recolonize the rest of the world.

It would take more than a Chixalub to wipe us out. It sure would fuck with us, but there would still be survivors.

[Alyrium Denryle]

OK, but the Chixalub event obviously did not roast the entire planet because large animal life existed afterwards.

Shit got lucky sometimes. Hanging out in a shallow depression, hide in a cave, be aquatic and dive.

In the end, nothing over 25 kilos survived. Between the initial impact, firestorm and climatic devastation, only dietary generalists (and stuff that could hibernate) below 25 kilos made it, and they radiated back out and rediversified.

We be fucked. Agriculture is not possible in this environment and we are too large to subsist on the scraps of food that will be available to us after impact. Toast.

[Broomstick]

Hmm.... I wonder how much canned/preserved food would be accessible to survivors?

I get what you're saying, but we're not quite like the rest of the animal kingdom. It may or may not give us an edge.

[Adam Reynolds]

The second scenario is literally impossible. Any asteroid that would hit earth and was that large would be rather predictable. Orbital mechanics are one of those problems that humanity has more or less solved. Whether or not we could deflect it would be a question, but we could certainly know it is coming in advance.

[Simon_Jester]

That is... not entirely certain. I don't think we have all the near-Earth asteroids charted, and sometimes we don't find them until they hurtle through the Earth-Moon system at speed. Which is pretty close to "asteroid hits us without warning."

[Simon_Jester]

OK, but the Chixalub event obviously did not roast the entire planet because large animal life existed afterwards.

Shit got lucky sometimes. Hanging out in a shallow depression, hide in a cave, be aquatic and dive.

In the end, nothing over 25 kilos survived. Between the initial impact, firestorm and climatic devastation, only dietary generalists (and stuff that could hibernate) below 25 kilos made it, and they radiated back out and rediversified.

We be fucked. Agriculture is not possible in this environment and we are too large to subsist on the scraps of food that will be available to us after impact. Toast.

Normal agriculture would be impossible. Something bizarre like ranching bunny rabbits who live on mushrooms raised in the massive amounts of decaying organic matter left behind by the impact... not so sure.

[MKSheppard]

What does SDN think?

Africa dies, as does large parts of South America. The more industrialized South American , Asian, European and North American nations survive the strike.

Afghanistan becomes a graveyard. Nobody cares.

[Simon_Jester]

What do heavily industrialized nations do that enables them to survive the strike, where less industrialized ones do not?

[Broomstick]

If the space rock falls on a particular industrialized country the level of industry doesn't matter, that spot is gone.

[MKSheppard]

What do heavily industrialized nations do that enables them to survive the strike, where less industrialized ones do not?

Heavily industrialized nations have you know, a common semblance of actual fucking cohesiveness. They're more than just 50 zillion little tribes squabbling (Africa, I see you).

[Simon_Jester]

Shep, I think that one depends on the country in question.

A lot of African nations are squabbly, but that doesn't necessarily mean everybody dies, because they're also the places where people are accustomed to surviving with minimal infrastructure.

Conversely, a lot of developed nations are highly dependent on organized transportation and only a small fraction of the population has skills that are transferable into what you'd need to survive in the wake of a massive asteroid strike.

[Guardsman Bass]

It really depends on how much time we have to prepare. Some types of food can store for an extremely long time if done right, and we'd supplement that with greenhouse/hydroponic food grown after the impact (assembling the greenhouses after conditions are such that we can assemble them outside again). But for that you need power, so you'd need to prepare power supplies to support that afterward, and so on and so forth. The Wikipedia section on the effects of the impact say the worst of it would probably be over within 10 years - after that, we could take a shot at growing cool-weather crops and other food on the surface again.

Location matters a lot, too. The best possible location for humanity's survival would be . . . Antarctica, maybe? If it hit smack in the middle of the East Antarctica ice sheet. That's going to melt a fuck-ton of ice and cause sea level rises (and possibly worse from water vapor kicked up into the atmosphere), but it would be as far as possible from the most inhabited parts of Earth and the ice sheet would take a lot of the energy.

[jwl]

That is... not entirely certain. I don't think we have all the near-Earth asteroids charted, and sometimes we don't find them until they hurtle through the Earth-Moon system at speed. Which is pretty close to "asteroid hits us without warning."

We don't have all of the near-earth asteriods tracked but we do probably have all the KT-level near earth asteriods tracked. This discounts comets though, which may be both KT level and too far out right now for us to track.

[biostem]

The issue would be if the impact generates a dust cloud that blocks out the sun. If it does, then starvation will be the likely cause of death of billions. Unless people can either start subsisting on fungi, (there shouldn't be a shortage of dead and decaying matter for them to subsist on), or people work out a way to farm hydrothermal vent life, things will be pretty bleak. I suppose it might be possible to use what little resources survive to build a few nuclear power plants and use them to power UV lamps to grow plants in greenhouses or such, but that's still not going to feed everyone. Perhaps there will be a few strains of plant that can survive on the weak UV rays that do manage to get through the clouds.

[Purple]

How much warning would get get of this? Because if we have a year or two we could expand some of the larger mines and cold war bunkers and save a lot of people that way. Just add (if not already there) an atomic reactor for power, set up some hydroponics and a supply of canned food to last for generations and pack it with as many people as is the minimum necessary for breeding without long term problems. Also like frozen sperm samples and stuff. Wait a couple of centuries than recolonize the earth.

[Broomstick]

Geez, guys, what makes you think the necessary infrastructure for nuclear power is going to survive?

Maybe Cold War era bunkers, but they'll have to be very far from any coast due to the tsunamis, stocked, and functional. A lot of them have probably fallen into disrepair at this point.

Best bet for survival would be a large supply of preserved foods to get you past the initial devastation

Oh, heavens - the Mormons will survive! Up in the mountains of Utah, tradition of keeping a year's supply (or more) of food on hand...

[Purple]

Geez, guys, what makes you think the necessary infrastructure for nuclear power is going to survive?

Given that the americans once burred an atomic power plant under the Greenland ice and it worked fine until the shifting ice forced the base to evacuate I'd say that putting a reactor in an underground bunker or mine shaft should work just fine.

Maybe Cold War era bunkers, but they'll have to be very far from any coast due to the tsunamis, stocked, and functional. A lot of them have probably fallen into disrepair at this point.

Probably yes, but really nothing we can't clean up if given enough forward notice and motivation.

[Guardsman Bass]

Geez, guys, what makes you think the necessary infrastructure for nuclear power is going to survive?

Maybe Cold War era bunkers, but they'll have to be very far from any coast due to the tsunamis, stocked, and functional. A lot of them have probably fallen into disrepair at this point.

It depends on how much warning time we have, since FireNexus didn't specify that in the OP. If we have 5-10 years warning (or more), then we could do some pretty drastic preparations: massive bunkers and shelters so that people can survive the world-wide firestorm, stockpiles of food and other goods/supplies, and a system to monitor the outside conditions.

Odds are it's going to land somewhere in one of the oceans, so you evacuate everyone behind mountain ranges inland (at least in the US).

Of course, with that much warning we could also try and deflect the asteroid. This is just in case the effort fails.

Best bet for survival would be a large supply of preserved foods to get you past the initial devastation

Oh, heavens - the Mormons will survive! Up in the mountains of Utah, tradition of keeping a year's supply (or more) of food on hand...

Their odds of survival would definitely go way the hell up, as long as they remembered to keep a year's worth of drinkable water and a water filter as well.