Preparing for the Big One

Oct 21, 2019
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Preparing for the Big One

It isn’t a question of if the Earth will eventually be hit by a large comet or asteroid, but when it will be hit. Again.

That sentiment is almost a cliché, but like many clichés it is quite true. The most recent large impact was at Chicxulub on the Yucatan Peninsula about 65 million years ago. But there are scars on the Earth of even larger impacts in the past. In fact, the Earth has more impact craters than the Moon. It is only due to weathering and tectonic movements that their remnants are sometimes difficult to recognize. Meteor Crater near Winslow Arizona is one of the most recognizable craters, about a mile across and formed only 50,000 years ago.

The most recent potentially devastating event happened over Tunguska near the Podkamennaya (Lower Stony) Tunguska River in what is now Krasnoyarsk Krai of Russia, at around 7:14 a.m. on June 30, 1908. A large comet or asteroid fragment exploded about 5-10 kilometers above the ground, leveling about 80 million trees over an area of about 2150 square kilometers. (830 square miles). The strength of the blast has been estimated at about 10-15 megatons. Had this explosion occurred over a city like New York, it would have leveled the entire city.

o, we know that rather large asteroids or comets are still capable of hitting Earth. And although impacts such as Meteor Crater or Tunguska would create intense local damage, a much larger object could potentially destroy all or most of the life on Earth.

What can we do to prepare? Well, the obvious first and best choice would be to build a network of satellites capable of detecting and diverting potential planet busters. That is not as easy as it might seem at first. There are a lot of problems associated with attempting to destroy or divert a large astronomical body headed towards Earth. Unlike the popular movie scenarios, we couldn’t just put something together in a few months and succeed in saving the world. But that isn’t what this paper is about. This paper is about preparing to survive an unavoidable impact by a large asteroid or comet.

So, what can we do? What do we need to survive? We can expect a very large impact to devastate most of the surface of the Earth, not from the initial impact, but from the fire and ash blasted into the air, circling the globe in a blanket of dust and gas. This cloud would rain burning embers down upon the Earth, starting wildfires everywhere. Firefighting services would be too overwhelmed to even begin to put a significant portion of the fires. 90% of the fires would burn unchecked. But it even more deadly, the global cloud would block out the light from the Sun. The global firestorm would be followed by years of freezing temperatures, with little or no Sunlight reaching the ground. Eventually, the cloud would dissipate, but virtually all life on Earth would have perished.

Survival would require extensive preparations. For the purposes of this discussion we will assume a warning of 2 years before impact. I will list the minimum requirements for a high probability of survival.

Shelter – Underground shelters would be needed. Although above ground shelters could be built, the advantage of the underground shelters would be protection from the extreme cold, and a greatly reduced requirement of energy to keep warm. In addition, during the first few months especially, roving gangs and individuals who have survived above ground, will no doubt be looking for food and shelter, and be willing to resort to any means to get it. It would probably be vital to survival to be completely invisible to anyone wandering by.

Food – Enough food for the occupants of the shelter for about five years would be required. We can assume that the “nuclear winter” will dissipate in about two years, but it may last up to three years. Once the extreme cold is past, it would take a minimum of a year to begin to harvest food again.

Water – Although a deep well may supply needs for the survivors, there is no way to predict what the global cataclysm may do to underground water supplies. It would be wise to construct very large underground water storage tanks. For 10 people that would be about 25,000 gallons.

Air – The outside air will no doubt be contaminated with many poisonous substances for a long time. Therefore, air filtration systems would have to be used to supply clean air. That would include more than particle filters. Filters would be required that could filter out poisonous gasses. Those would be expensive and have limited life spans, so a large number would be required. CO2 absorbers would also be needed.

Power – A critical part of survival would be the availability of power to supply light, heat, and to run ventilators etc. Providing enough power will be a major problem. Solar would not work. Wind turbines would probably work, but require a great deal of maintenance. They would also attract marauders and roving gangs. Geothermal would be the best option if practical in your area. If far enough in the future, personal nuclear generators would be ideal.

Waste Disposal – The disposal of human waste and garbage will be no small matter. A large underground septic system should be constructed to handle human waste. Garbage might be stored, although it would be wise to recycle as much as absolutely possible. Also, there would be a need to take care of deceased residents.
 
Dec 11, 2019
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Its seems like more people are worried about so called climate change than an asteroid. I think because you can't make any money off of scaring people with asteroids.lol! They and Al Gore can make more money on scaring people with climate change especially since they

But your article makes very good sense. It would be nice to have an underground bunker with 5 years of supplies.
 
Jan 10, 2020
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Preparing for the Big One

It isn’t a question of if the Earth will eventually be hit by a large comet or asteroid, but when it will be hit. Again.

That sentiment is almost a cliché, but like many clichés it is quite true. The most recent large impact was at Chicxulub on the Yucatan Peninsula about 65 million years ago. But there are scars on the Earth of even larger impacts in the past. In fact, the Earth has more impact craters than the Moon. It is only due to weathering and tectonic movements that their remnants are sometimes difficult to recognize. Meteor Crater near Winslow Arizona is one of the most recognizable craters, about a mile across and formed only 50,000 years ago.

The most recent potentially devastating event happened over Tunguska near the Podkamennaya (Lower Stony) Tunguska River in what is now Krasnoyarsk Krai of Russia, at around 7:14 a.m. on June 30, 1908. A large comet or asteroid fragment exploded about 5-10 kilometers above the ground, leveling about 80 million trees over an area of about 2150 square kilometers. (830 square miles). The strength of the blast has been estimated at about 10-15 megatons. Had this explosion occurred over a city like New York, it would have leveled the entire city.

o, we know that rather large asteroids or comets are still capable of hitting Earth. And although impacts such as Meteor Crater or Tunguska would create intense local damage, a much larger object could potentially destroy all or most of the life on Earth.

What can we do to prepare? Well, the obvious first and best choice would be to build a network of satellites capable of detecting and diverting potential planet busters. That is not as easy as it might seem at first. There are a lot of problems associated with attempting to destroy or divert a large astronomical body headed towards Earth. Unlike the popular movie scenarios, we couldn’t just put something together in a few months and succeed in saving the world. But that isn’t what this paper is about. This paper is about preparing to survive an unavoidable impact by a large asteroid or comet.

So, what can we do? What do we need to survive? We can expect a very large impact to devastate most of the surface of the Earth, not from the initial impact, but from the fire and ash blasted into the air, circling the globe in a blanket of dust and gas. This cloud would rain burning embers down upon the Earth, starting wildfires everywhere. Firefighting services would be too overwhelmed to even begin to put a significant portion of the fires. 90% of the fires would burn unchecked. But it even more deadly, the global cloud would block out the light from the Sun. The global firestorm would be followed by years of freezing temperatures, with little or no Sunlight reaching the ground. Eventually, the cloud would dissipate, but virtually all life on Earth would have perished.

Survival would require extensive preparations. For the purposes of this discussion we will assume a warning of 2 years before impact. I will list the minimum requirements for a high probability of survival.

Shelter – Underground shelters would be needed. Although above ground shelters could be built, the advantage of the underground shelters would be protection from the extreme cold, and a greatly reduced requirement of energy to keep warm. In addition, during the first few months especially, roving gangs and individuals who have survived above ground, will no doubt be looking for food and shelter, and be willing to resort to any means to get it. It would probably be vital to survival to be completely invisible to anyone wandering by.

Food – Enough food for the occupants of the shelter for about five years would be required. We can assume that the “nuclear winter” will dissipate in about two years, but it may last up to three years. Once the extreme cold is past, it would take a minimum of a year to begin to harvest food again.

Water – Although a deep well may supply needs for the survivors, there is no way to predict what the global cataclysm may do to underground water supplies. It would be wise to construct very large underground water storage tanks. For 10 people that would be about 25,000 gallons.

Air – The outside air will no doubt be contaminated with many poisonous substances for a long time. Therefore, air filtration systems would have to be used to supply clean air. That would include more than particle filters. Filters would be required that could filter out poisonous gasses. Those would be expensive and have limited life spans, so a large number would be required. CO2 absorbers would also be needed.

Power – A critical part of survival would be the availability of power to supply light, heat, and to run ventilators etc. Providing enough power will be a major problem. Solar would not work. Wind turbines would probably work, but require a great deal of maintenance. They would also attract marauders and roving gangs. Geothermal would be the best option if practical in your area. If far enough in the future, personal nuclear generators would be ideal.

Waste Disposal – The disposal of human waste and garbage will be no small matter. A large underground septic system should be constructed to handle human waste. Garbage might be stored, although it would be wise to recycle as much as absolutely possible. Also, there would be a need to take care of deceased residents.
 
Jan 10, 2020
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Another life destroying impact will occur, I think the average frequency has been estimated to be about every 200 million years. Given the low odds of it happening in the near future the question is - should we be prepared or simply risk it? Detection is not overly good at the moment, I understand a bus sized asteroid passed between the moon and earth recently and took everyone by surprise. Something really big (a kilometre or more across) will need to be detected very early to give heaps of time for a response. It is believed diverting the trajectory of the body is the best option. A nuclear blast on one side could achieve this. It would need to happen well before it's estimated arrival. Any course change so induced would be slight which is why such a tactic will need to be done so as to give the trajectory change sufficient time to cause the object to miss.
 
Dec 11, 2019
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Another life destroying impact will occur, I think the average frequency has been estimated to be about every 200 million years. Given the low odds of it happening in the near future the question is - should we be prepared or simply risk it? Detection is not overly good at the moment, I understand a bus sized asteroid passed between the moon and earth recently and took everyone by surprise. Something really big (a kilometre or more across) will need to be detected very early to give heaps of time for a response. It is believed diverting the trajectory of the body is the best option. A nuclear blast on one side could achieve this. It would need to happen well before it's estimated arrival. Any course change so induced would be slight which is why such a tactic will need to be done so as to give the trajectory change sufficient time to cause the object to miss.
They are more worried about climate change because they make more money on it because they can tax the slaves more for their so called carbon footprint. Hard to make money on an asteroid destroyer. The fact is they really don't care about you they just want your money so they can get out of here themselves.
 
Dec 29, 2019
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preparing to survive an unavoidable impact by a large asteroid or comet.
I think advocating for development of actual defenses, that can divert big meteorites makes more sense than advocating for survival bunkers. We will have continue to have bunkers, but they are very unlikely to be part of any overall planned response; they will be for the super wealthy who can provide their own or military/government bunkers that are there, at least ostensibly, for other reasons than surviving world killing catastrophes. A specific commitment to saving the human race via planned bunkers equipped to survive and repopulate the world is good fiction but I am not sure it is good as actual government policy.

Its seems like more people are worried about so called climate change than an asteroid. I think because you can't make any money off of scaring people with asteroids.lol! They and Al Gore can make more money on scaring people with climate change especially since they
When every top level science report for the past three decades - no matter who commissioned it - says the climate problem is real and serious, it is real and serious. I want and expect my government to base policy on the consistent and persistent science based expert advice.

US National Academy of Sciences -
Climate change is happening today. Scientists have known for some time, from multiple lines of evidence, that humans are changing Earth’s climate, primarily through greenhouse gas emissions.

The evidence is clear and compelling. Earth’s atmosphere and oceans are warming, the magnitude and frequency of extreme climate and weather events are increasing, and sea level is rising along our coasts.
Giving greater priority to a major problem unfolding now, that will impact the lives of people now living for the entirety of their lives - and already is - than to one with, say, a 1 in 100,000 year likelihood of occurring makes sense to me.

I think addressing climate change - and other Earthly problems - is an essential prerequisite to maintaining a world economy and society capable of developing a viable meteor defense. Fail on climate change and meteor defenses won't be possible.
 
Jan 9, 2020
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There is no consensus on climate change. Much of what Al Gore said has been debunked because there is so much fraud behind it. This is not to say we have not had warm periods. It's too complex a science with lots of feedback loops than to blame a gas that occupies only 0.038% of the atmsophere. Indeed climate does change; it is a matter of how drastic a change is or how fast. Anyone who reads this 97% figure-that has been debunked too. Politicans are great at citing numbers in order to persuade to their side. One recent reveleation that I came across is that the top of the atmosphere (exosphere) has warmed a few degrees. I also note that when I look up the tilt of our axis it is reported as 23.46. Every book I read growing up said 23.5. I don't know if they just rounded off or if there has been a few ticks of change. Jan 2019 scientists were reporting the start of a possible--emphase possible magnetic reverse in the earth's magnetic field.
 
Oct 21, 2019
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I think advocating for development of actual defenses, that can divert big meteorites makes more sense than advocating for survival bunkers. We will have continue to have bunkers, but they are very unlikely to be part of any overall planned response; they will be for the super wealthy who can provide their own or military/government bunkers that are there, at least ostensibly, for other reasons than surviving world killing catastrophes. A specific commitment to saving the human race via planned bunkers equipped to survive and repopulate the world is good fiction but I am not sure it is good as actual government policy.
I do not appreciate you taking my comment out of context and creating your Strawman Argument. My complete comment was:
What can we do to prepare? Well, the obvious first and best choice would be to build a network of satellites capable of detecting and diverting potential planet busters. That is not as easy as it might seem at first. There are a lot of problems associated with attempting to destroy or divert a large astronomical body headed towards Earth. Unlike the popular movie scenarios, we couldn’t just put something together in a few months and succeed in saving the world. But that isn’t what this paper is about. This paper is about preparing to survive an unavoidable impact by a large asteroid or comet.” , the key word being unavoidable.

When every top level science report for the past three decades - no matter who commissioned it - says the climate problem is real and serious, it is real and serious.
This discussion is regarding major Asteroid or Comet impacts, NOT climate change. Please start another thread on that in the appropriate forum.
 
Dec 11, 2019
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When every top level science report for the past three decades - no matter who commissioned it - says the climate problem is real and serious, it is real and serious. I want and expect my government to base policy on the consistent and persistent science based expert advice.
If they really cared about the environment we would be using Tesla's free energy machine and many inventions have been made to run automobiles on other than oil. The bottom line is how much money can be made.

Sure when the books are cooked and funded by governments they can make up anything they want about climate change. Not to mention the aerosol spraying and geoengineering that are the big culprits in the climate changing. They fail to mention that.

Have you ever heard of Problem, Reaction, Solution? First the globalists create the problem. You get the reaction from the public for them to fix it. Then they give the solution they wanted all along. Such as one example is carbon taxes. Soon you will be taxed on the air you breath out if people don't get a clue to what is really going on.
 
Dec 29, 2019
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This discussion is regarding major Asteroid or Comet impacts, NOT climate change. Please start another thread on that in the appropriate forum.
Fine with me; I am not interested in debating delusional conspiracy theorists. Truthseeker007 brought climate change denial into the discussion. I just wanted to make sure people here know that I accept and trust the mainstream science on that matter - as should our governments.

My complete comment was:
What can we do to prepare? Well, the obvious first and best choice would be to build a network of satellites capable of detecting and diverting potential planet busters. That is not as easy as it might seem at first. There are a lot of problems associated with attempting to destroy or divert a large astronomical body headed towards Earth. Unlike the popular movie scenarios, we couldn’t just put something together in a few months and succeed in saving the world. But that isn’t what this paper is about. This paper is about preparing to survive an unavoidable impact by a large asteroid or comet.” , the key word being unavoidable.
If a much lesser event than that happens any time soon then it will indeed be unavoidable. Bunkers would offer some hope of survival, but only for a very tiny portion of the world's population. I doubt that the survivors would be able to restore and sustain an advanced, comprehensibly capable industrial economy, but probably homo sapiens would survive and endure.

Whether, knowing a killer meteorite was coming, plans to build and stock and select people to occupy "public" bunkers in order to repopulate the world after could be brought into play becomes a political/social question - I expect that would present serious difficulties; there would be abundant claims that it is being made up - "first the bunkerists create the problem then give the solution they wanted all along". Some people would still be denying the asteroid even exists right up until it hits.

Bunkers can only be for a small few; the scale of construction for large numbers is enormous, even without all the added difficulties of being hardened enough for the earthquakes and fires, the tsunamis and floods.

Nuclear war bunkers would be hardened enough but major constructions, deep underground, with metres thick reinforced concrete and shock absorbers are seriously expensive. If specific to the purpose, there may be no requirement for that degree of hardening or even for going underground, but survival bunkers are not something that can be done at large scale in a hurry.

But you are talking about what such a plan might look like if it were I expect it would look much like you say in the opening post.

I would think power supply is absolutely crucial. Major government bunkers of nuclear capable nations can use nuclear - but I don't know how they manage cooling water.

I'm not sure how private bunkers would manage except by diesel or gas generators, with large quantities of fuel hoarded. The potential for extended periods where air intake/exhaust outlets could be blocked would be an issue. Solar would be unavailable for a long time. The ability to manufacture more is - like all advanced manufacturing - going to be a serious question; advanced technologies rely on convergence of multiple specialised materials and equipment and skills.

I think humans would survive - but may never reach the same technological capabilities.
 
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Dec 11, 2019
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Fine with me; I am not interested in debating delusional conspiracy theorists. Truthseeker007 brought climate change denial into the discussion. I just wanted to make sure people here know that I accept and trust the mainstream science on that matter - as should our governments.
Actually the fact of the matter is it is more delusional to trust governments and main stream science. I am definitely not the delusional one here. Do you even know what the definition of a conspiracy is? Even cops must develop their conspiracy theory on exactly went on in an investigation. You don't even want to get me started on how the term conspiracy theorist has become a negative connotation. That is a whole other subject.

But we must get back to the topic Asteroids and Comets because heavens no if we veer from the subject for a minute. Even though hardly anybody is even talking in here about it.

The fact of the matter is an asteroid and comet will hit us one day and there is no way to stop one and all this conversation will be meaningless when the human race has to start over again . That about sums up the whole topic. For one thing I sure wouldn't trust governments or anyone for that matter that have the power of a weapon that can take out an asteroid or comet. And if it is about survival the ones with all the power and money are going to let us die and not care at all and they already have their escape plan set up.
 
Oct 21, 2019
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If a much lesser event than that happens any time soon then it will indeed be unavoidable. Bunkers would offer some hope of survival, but only for a very tiny portion of the world's population. I doubt that the survivors would be able to restore and sustain an advanced, comprehensibly capable industrial economy, but probably homo sapiens would survive and endure.
Much of that would depend on the size and duration of the global dust cloud. A K-T level impact would destroy very little of the technology, tools, and equipment. The main problems for the first two years would be food and shelter. After that, all of the necessary technology would still be there, along with all of the knowledge to use it.
Whether, knowing a killer meteorite was coming, plans to build and stock and select people to occupy "public" bunkers in order to repopulate the world after could be brought into play becomes a political/social question - I expect that would present serious difficulties; there would be abundant claims that it is being made up - "first the bunkerists create the problem then give the solution they wanted all along". Some people would still be denying the asteroid even exists right up until it hits.
If there were two years warning, and they were absolutely certain it would hit Earth, there would no doubt be government run public shelters built. That is one aspect that would be a lot like in the movies, including lotteries, rioting for entry, and all sorts of mayhem. That would be localized around planned shelters. Best to avoid being anywhere near that.
Bunkers can only be for a small few; the scale of construction for large numbers is enormous, even without all the added difficulties of being hardened enough for the earthquakes and fires, the tsunamis and floods.
Bunkers would not have to be hardened against earthquakes. That is one thing very unlike the movies. Near the impact, massive devastation. Everywhere else, spot fires from falling ash for hundreds of miles. Further away, ash and dust obscuring the Sun and falling on the ground. If anything, bunkers that were visible would have to be hardened against raids.
Nuclear war bunkers would be hardened enough but major constructions, deep underground, with metres thick reinforced concrete and shock absorbers are seriously expensive. If specific to the purpose, there may be no requirement for that degree of hardening or even for going underground, but survival bunkers are not something that can be done at large scale in a hurry.
Again, from what we know of the Chixalub impact, the shock damage was very localized, perhaps several hundred miles. Salt mines and other mines, natural caves, even Subway tunnels would be plenty of protection. The main problem would be food, water, and security.
I would think power supply is absolutely crucial. Major government bunkers of nuclear capable nations can use nuclear - but I don't know how they manage cooling water.
Power is always an issue. The supplies of coal, oil, natural gas, and gasoline would last for quite a while is used carefully. All of the heaters and other equipment would still be available. The power might even outlast the food supply
I'm not sure how private bunkers would manage except by diesel or gas generators, with large quantities of fuel hoarded. The potential for extended periods where air intake/exhaust outlets could be blocked would be an issue. Solar would be unavailable for a long time.
Some would be more prepared than others. There are some that are that prepared now. LDS members are required to have two years of food stored. I know some of them, and they have other supplies as well. If Utah is not ground zero, they might do quite well.
I think humans would survive - but may never reach the same technological capabilities.
I disagree. There would be fewer people, but the technology would still be there, mostly intact.[/QUOTE]
 
Dec 29, 2019
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I think you are underestimating the destruction from a Chicxulub scale impact. Whether destructive Earthquakes would occur globally? I won't insist on it. Tsunamis, especially if it came down in deep ocean, would take out everything around the entire coasts of the ocean it landed in.


Simulation showing how extreme atmospheric heating and potential wildfires might have proceeded show as much as a third of the planet subject to it. Whole continents will cook and burn. I would not expect much infrastructure to survive and be usable even outside these areas when the bunker doors are opened -
S

Mostly I disagree that, even where whole industrial regions are effectively intact that these could be put back into production by the survivors; without the original workforce, power supplies, working transport systems and supply chains they will be unusable.

I don't know how many people could be expected to fit into bunkers or how well stocked they could be; I'd call >1% in well built, well stocked, well managed to be bunkers optimistic. If agriculture takes more than a few years to achieve reliable production the survival rate will go down - the likelihood that extreme weather conditions that can kill crops and livestock persist for as long as decades looks real to me.

Post apocalyptic technology is going to be scavenged rather than manufactured. I think they will lose their capabilities over time. By the time the population has grown sufficiently to support an advanced industrial economy they may find it more difficult, despite intact libraries to get inspiration from, than it was the first time around.
 
Oct 21, 2019
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Your predictions are probably based upon lack of perspective. After reading my original post which I wrote about 12 years ago, I realized I also lacked perspective at that time. After further research, I edited my OP according to more recent information, and a new perspective obtained from doing some calculations.

Simulation showing how extreme atmospheric heating and potential wildfires might have proceeded show as much as a third of the planet subject to it. Whole continents will cook and burn. I would not expect much infrastructure to survive and be usable even outside these areas when the bunker doors are opened -
The majority of the surface of the continents would not burn due to the impact. However, there would eventually be more fires in cities where people began burning wood, paper, books, furniture etc. for warmth. In all areas where there were no fires, the infrastructure would remain intact.

Mostly I disagree that, even where whole industrial regions are effectively intact that these could be put back into production by the survivors; without the original workforce, power supplies, working transport systems and supply chains they will be unusable.
Rebuilding would be very slow to start with, starting with basic needs. Eventually, as the population increases, most of the industries could be brought back. That would take decades at least.

I don't know how many people could be expected to fit into bunkers or how well stocked they could be; I'd call >1% in well built, well stocked, well managed to be bunkers optimistic. If agriculture takes more than a few years to achieve reliable production the survival rate will go down - the likelihood that extreme weather conditions that can kill crops and livestock persist for as long as decades looks real to me.
There are probably more survivalists out there than you realize. We have large stores of food, fuel, and other necessities, along with the skills to survive major disasters and TEOTWAWKI. Included in our supplies are the tools and items necessary to literally start all over again if necessary. That means that, in addition to any government or commercial shelter systems, there would be thousands and thousands of shelters capable of sustaining 1, 2, 5, 10 or so people for the duration.

Post apocalyptic technology is going to be scavenged rather than manufactured. I think they will lose their capabilities over time. By the time the population has grown sufficiently to support an advanced industrial economy they may find it more difficult, despite intact libraries to get inspiration from, than it was the first time around.
Scavenged at first for necessary supplies. Most industrial factories will not have items needed by the first survivors. I think that most of the machinery and stockpiles of raw materials will survive until they can be put back into production.
 
Dec 29, 2019
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Again, I think you are seriously underestimating the destruction. From the accompanying description to that simulation -
Like countless trillions of meteors, the debris heated the atmosphere and surface temperatures so high that vegetation on the ground was ignited.
That potential wildfire simulation is where air temperatures could get hot enough to get spontaneous fires! Hundreds of degrees C.

Having been in the midst of Australia's fires I can assure you that wherever there are people there is never any shortage of sources of ignition. Under such extreme heat any fires would propagate very fast - through the air via flammable vapors alone - and unlike Chicxulub human habitation means fires will get started. Approaching virtual certainty.

I think most cities, even starting wet and cold, would catch fire under such conditions and those fires would be unstoppable. If a third of the world gets that hot, likely most of the world would reach lethal outdoor temperatures - with yet more fires.

thousands and thousands of shelters capable of sustaining 1, 2, 5, 10 or so people for the duration.
Being generous, a 100,000 such shelters would be perhaps 500,000 people. As a single functional civilisation that would be significant. Scattered across a ruined continent it is not a functional civilisation. If they get desperate enough - food and fuel runs out - they could turn to cannabilising each other, literally as well as figuratively. Other survivalists would be the only living game to hunt.

What is well stocked? Bunkers with 2 years of fuel and food sounds woefully inadequate to me, when it could take as long as a decade for the freeze to thaw and acid rain to stop and even at that point it will probably be very difficult to grow any crops successfully. I don't think small private bunkers are likely to do as well as you think with that scale of disaster.

Included in our supplies are the tools and items necessary to literally start all over again if necessary.
You won't have functional coal mines or oil refineries or even functional oil wells for energy. No power stations, no power grid, no factories that are functional. Even the coal or charcoal to support blacksmithing could be unavailable.

Most of all you won't have a working economy - and my impression of survivalists is that many go into their bunkers heavily armed intending to forcefully resist loss of independence and sharing of their hoards - yet I think sharing resources would be essential for collective survival; by themselves, independently, their chances will be lessened, not improved. I think the survivalist mindset is probably wrong for restarting civilisation under extreme conditions and it will be the large, well stocked military bunkers that offer the best chances and even those could struggle to keep people fed long enough to be able to reliably grow crops outdoors. Even with them I think the chances of failure, of human extinction, would be high.
 

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