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The Underappreciated Risks of Severe Space Weather
circletimessquare notes a New Scientist piece calling attention to a recent study by the National Academy of Sciences, which attempts to raise awareness of the dangers of severe solar electromagnetic storms. "In 1859, amateur astronomer Richard Carrington noticed 'two patches of intensely bright and white light' near some sunspots. At the same time, Victorian era magnetometers went off the charts, stunning auroras were being viewed at the equator, and telegraph networks were disrupted — sparks flew from terminals and ignited telegraph paper on fire. It became known as the Carrington event, and the National Academy of Sciences worries about the impact of another such event today and the lack of awareness among officials. It would induce un-designed-for voltages in all high-voltage, long-distance power lines, and destroy transformers, as Quebec learned in 1989. Without electricity, water would stop flowing from the tap, gasoline would stop being pumped, and health care would cease after the emergency generators gave up the ghost after 72 hours. Replacing all of the transformers would take months, if not years. The paradox would be that underdeveloped countries would fare better than developed ones. Our only warning system is a satellite called the Advanced Composition Explorer, in solar orbit between the Sun and the Earth. It is 11 years old and past its planned lifespan. It might give us as much as 15 minutes of warning, and transformers might be able to be disconnected in time. But currently no country has such a contingency plan."
Surely you should be glad it isn't "mis-undesigned-for", knowing /. editors.
Sounds like another good reason for those who can to take a serious look at getting off the grid, or at least being able to disconnect from the grid and mostly sustain their own needs on the homefront. Kinda funny that wacky survivalists might have the last laugh in an event like this.
512 MB RAM, 20 GB disk, 200 GB transfer, five datacenters. $19.95/month.
Like many others here, I don't prescribe to these doomsday scenarios that get rolled onto center stage every so often.
I remember when the northeast US had a power outage that lasted a few days just a few years back. It was no where near as dramatic or dire as this summary suggests the situation could be. I still had water and gas in Ohio.
Overclockers
I live in the countryside. Well, more the suburbs now. Since time immemorial people in rural areas have had to deal with power cuts and blackouts, sometimes lasting days.
Amazingly, the vast majority survived.
Candles, flashlamps, tinned food and a fireplace get you through most of the time. Bedtime usually comes earlier. Yes you can't play video games or listen to your mp3s, but there are book, or at worst other people with which you can occupy your time.
As much as the thought of millions of pampered city dwellers wailing helplessly in the darkness might amuse me, I can not imagine that their lives are so different to country people as to make survival a difficult prospect. Yes, it could take days for the power to come back. But people will make it. Business will make it. Society and civilization as we know it, will probably make it.
Yes. I know that sci-fi-esque stories using words like "electromagnetic", "storm" and "disaster" might worry those with active imaginations. I know that newspapers love to print them next to their ad pages. Someday, someone might even make a Hollywood movie about just such a tale, and then people will really start talking about it. But people must always try to remember that just because someone says something, that doesn't mean they are correct.
May the Maths Be with you!
As useless as your post was, that was exactly my thought. We don't spend much time worrying about asteroid impacts, either, even though those have a greater potential for harm. There's just not enough that we can do about it.
Same thing goes for local supernovae or gamma ray bursts. We could also be living in a false vacuum. At any moment all life on Earth could be wiped out entirely; If broken transformers are all we have to worry about from solar flares, I for one am not going to lose much sleep over it.
Those who advocate genocide deserve every protection afforded by law, and none afforded by common human decency.
That's just flat out wrong.
ACE might have a better ground network (let's face it, it's easier to talk to as it's at L1), but STEREO-Behind can see areas of the sun that aren't visible from any other solar-observing mission. It's also remote sensing (ie, telescopes), so it doesn't have to wait until it gets hit by an event. (at which point, we're looking at the last 1M miles of a 93M mile trip)
There's also instruments that have proven space-weather benefits on SOHO, but that's even older than ACE. I'm not going to say that ACE isn't the most important satellite in NOAA's eyes for predicting space weather (and some of their space weather folks have even mentioned that they might have to put up a similar satellite when ACE finally fails), but saying it's the only warning system discounts all of the other solar-observing missions used for space weather forecasting.
Build it, and they will come^Hplain.
It's time to build a really damn huge tinfoil hat...
The risk might not be as great in the near future as described. For one, solar flares large enough to do such damage are rare. Also in now appears that the sun is entering a more quiet phase, the next solar cycle that should have started by now hasn't, and the predictions for max sun spot numbers for the next cycle have been done graded several times. Short wave radio reception will probably not be as good as it was in the past 20 years. The Canadian flare incident happened during one of the more active solar periods, perhaps the last one for next century.
Except that an event that happened 150 years ago seems more likely to occur again in the near future than an event which happened 65 million years ago, or an event that hasn't happened since the formation of our solar system.
It's a question of the odds. A major electrical storm occurred within the last couple of centuries. A major asteroid impact - of the sort that would do worse damage to a wide area (not just knock down some trees in Russia) - haven't seen one probably since we dropped down from the trees.
Whether you're losing sleep over it is one thing. whether we, when awake in the daytime, should be hardening our electrical grid against surges from space - well, that's a real question. Prudence doesn't mean just acting when you get scared enough that you can't sleep at night.
"with their freedom lost all virtue lose" - Milton
As a cyborg (literally, if technically) I have to wonder what such a solar electrical storm would do to implanted electronic medical devices, such as my pacemaker. Any knowledgeable insights? If this shuts down, I'm history in seconds.
Can we get a "-1 Wrong" moderation option?
Everyone should know how to build a basic cooking fire. Everyone should have at least one solar panel. Everyone should have spare water. Everyone should be able to kill & gut a fish, gopher, (or neighborhood dog if necessary). It seems like everyone today looks toward the government for help during emergencies when they should be relying on family and community.
If a big earthquake hits or a big solar flare lands... the government isn't going to get help to you for at least TWO WEEKS.
If you don't think loss of the entire power grid would deeply affect your life, I have to wonder where you live (and that's being kind)
Last time a major TEOTWAWKI event was looming (Y2K), I described the threat to my father in great detail. His response: [shrug] "I'll throw another log on the fire and go back to my book." True enough, my folks' lives are pervaded by self-sufficiency, including extensive wood heat, well water and homegrown food. Society shuts down, they just spend a few minutes adjusting and carry on.
But ... you wouldn't guess that at a glance. They have elegantly integrated the survivalist mindset with modern conveniences, enjoying everything technology has to offer without worries of what to do if the grid shuts down indefinitely. Everything has a low-tech backup, preparations for self-sufficiency are ongoing and already in use.
You can live a "survivalist" lifestyle, and still be fully "wired". The two ways of life are not diametrically opposed.
Can we get a "-1 Wrong" moderation option?
I really expect more from these guys.
That the power grid in this country would become a set of large antennas during a "carrington event" is an interesting problem. Inducted current would be tremendous. There would be fires, almost certainly, and blown transformers. Fusable links might help with the transformer issue, but I'm sure that some significant amount of transformer capability would be taken offline. Power stations would likely be immune from meltdown, but I don't know if standard trips would keep them all whole. Let's say that some 50% of the generating capacity (very generous), and 70% of the transformers (possibly low), were taken out by this event. A significant inconvenience, to be sure. Nothing that we, as individuals -- and as a society, could not handle. To assume, like the authors of this article, that the most powerful country in the world would simply roll-over is preposterous.
To propose, seriously, that "Modern Healthcare" would end in 72 hours when the emergency generators ran out of fuel -- this is ridiculous. The article's premise that modern civilization in our country would be thrown back to "third world" conditions is also completely without merit. Not to belittle the situation -- it would, in a word, suck. That said, we would rise to the occasion, I am sure of it.
Let's just, for a moment, reflect on how deep the fuel infrastructure is in this country. A power grid is not required for fuel distribution, though some level of power is required. Pumps that pump diesel can be run by generators, many refineries are capable of using their own product to generate power, and distribution of fuel to Hospitals and the like is a standard emergency procedure. Trains, tanker trucks, and ships continue to run. The transportation infrastructure would remain largely intact beyond the boundaries of very large metropolitan areas. The roads would continue to roll, and with it, teams of people working to fix the problem.
First, the plants, then the substations, then the cities and transmission lines. Would it be hard? Of course it would be hard. But we would continue to make it work, to adapt and overcome, and in the process make it better.
Bullshit, FUD and fearmongering...
In a case of a large scale power-system breakdown you don't go and try to bring it all back up all at once.
And you sure as hell don't sit on your ass crying, mourning the end of civilization and your X-box points.
Instead, teams of experienced technicians (you know... all those people with the various degrees in electrical engineering) start fixing the grid so that they can have parts of it running as soon as possible.
1 transformer, 2 transformers, 3 transformers, 4...
You lack the parts? Pillage the dead transformers. There is a PRETTY good chance you can take 2 or 3 dead ones and have 1 working in under 24 hours.
Fix the ones that CAN be fixed, leave the completely messed up ones for later replacement.
Don't have enough power to power the entire town cause the nation-wide system is down? DON'T.
Give one half of town 12 hours of power and then turn them off for the next 12 hours while the other half gets their 12 hours. Or 8. Or 6.
Hell... During the war (I'm from Bosnia) people used to steal cooling oil from the transformers (you can run chainsaws for cutting wood, and even cars on that stuff), artillery shells would explode next to them drilling them up with shrapnel, even the local power-plant got hit couple of times so bad that technicians had to take it off line to patch the pipes in the cooling towers.
Let me tell you... you get used to 4 hours of electricity per day (or less) VERY fast.
You leave the lights on to wake you up when it comes on.
Charge the batteries, cook, wash clothes, heat up the boiler and then go about your business waiting for better times.
Mit der Dummheit kämpfen Götter selbst vergebens
Neighbours doesn't count as preys?
Check out spaceweather.com. It has been around for some time, and has some excellent aurora galleries. Besides summarized ACE data, this website also features the techie-cool far side views of the sun from SOHO, computed using helioseismic holography. For the truly worried, they offer for-fee email solar-flare alert services, which also come in handy if you just want to know when to go out to look for auroras. Anyway, most of the site is non-subscription, and it's worth a look.
Asteroid impacts happen quite frequently, actually. Most of them are small. We have quite a bit of data on the frequency of large-scale asteroid impacts, and they have contributed several times to mass extinctions.
We have one (1) data point for solar flares of this magnitude. We cannot make *any* meaningful statements about frequency.
I wonder if government will ever take any precautions.
They didn't about the financial crisis.
The good, the evil and the vacuum tubes.
the problem with a powerful moving magnetic field is induction: it forces eletron flow in wires. emphasis: wires, or any piece of metal with a large ratio of length/ width/ height to the other two dimensions. a wire is a perfect victim for a moving magnetic field because it presents a very long cross section to the magnetic field, and thats what makes the induction powerful
meanwhile, your medtronic device is small and compact, so it doesn't present a large cross section to the magnetic field as it hits the earth
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
Yes, it is entirely a question of odds. Meteor showers happen on a regular--one might even say constant--basis. We have one data point for these damaging solar flares. You cannot draw meaningful conclusions of frequency from one event.
I can't imagine the cost of replacing or modifying every transformer in the grid would be remotely bearable. If it is possible to add this feature to upcoming installations at a marginal increase in cost, that would be prudent.
Unless it can be proven (unlikely) that these events will be regular enough to warrant replacing existing infrastructure, it should not be done. If this hasn't happened for more than 100 years, we can probably get away with fixing things if and when they break.
Those who advocate genocide deserve every protection afforded by law, and none afforded by common human decency.
"Wacky survivalists" is an historically very recent notion. For the bulk of mankind's history, having a well stocked larder-stores adequate to get you through to the next harvest season- and the means to supply yourself with adequate shelter and heat and water, etc based on your own and mostly local sources was quite the ordinary norm. It has only been the last two or three generations where that started to fall out of favor.
We have had numerous examples of much smaller and more localized infrastructure destruction, and the best observations have shown that areas start to suffer fast after a three day outage of general modern technology. Just in time delivery systems and centralized power and water and natgas delivery and so on are the main cause of that.without massive outside the region resupply, that's it, civilization falls apart rapidly. Three days isn't very long. If the event/disaster is much longer than three days, and no outside help is coming in (because the next region over is just as bad off, as the region next to that, etc), you'd see some pretty dire circumstances arise.
Here is one example for the US, we no longer maintain a national emergency bulk food stockpile. It used to be millions of bushels of this or that, dried milk and so on. We maintained that for decades, then they stopped and went to what is called set aside. This is due to farming changes and "the market". We- the government "we"- used to pay minimal price controls and stockpile various surplus foods, in order to maintain our domestic agricultural base through wild market swings and seasonal weather variations, but they more or less stopped that some time ago and now we have no stockpiled food, they sold the last of it off earlier last year finally.
In other words, on a very large scale, we have no backup civilization or big national pantry. It doesn't exist, just not there. The government has zero provisions to help the people in general at any national scale sized event. They have provisions to use military force to "stay in charge", they call it "maintaining continuity of government", that's it. We have a national petroleum reserve as the only exception, and it is in the form of just crude, it would still need refining and delivery-that's iffy enough in such a scenario to even be possible- (and even then most would go to the government and not the people).
On the other hand, there is nothing stopping people from instituting their own stores and provisions and having a personal backup protection scheme, the "wacky survivalists" type method that all our ancestors considered normal and a very good idea. In the community we still call it survivalism, but it has a less scary name now too, "practical preparedness". Here is a plain vanilla example, for roughly the same cash people put into a big screen plasma TV they can have a decent amount of long term dried stored food. For what a cheap laptop or other "must have" electronic gadget of the month costs, you can have a pretty decent gravity powered water filter. The folks in suburbia and in the hinterland get laughed at a lot as having unsustainable lifestyles, but they are living in the only places where you can have a rationally large enough local garden and access to alternative water supplies, etc, along with firewood. Choices one can choose now in other words. All the big cities would collapse rapidly in such a national sized electronic disaster as in TFA, it would become beyond ugly, right up to and including cannibalism.
Basically, the government sucks when it comes to national and practical "civil defense". They only have a military solution. The military doesn't produce anything, it just takes it/spends it/wears it out. Look at the recent articles about the relatively small numbers of homeless in California, possibly our richest state. They can't even deal with such a teeny tiny homeless situation at very low numbers adequately. Extrapolate those numbers from thousands to tens of millions or more and it becomes easy to see the problems...
So it is up to the individual now to decide to incorporate a practical preparedness plan and alter lifestyle a little bit, the article scenario is only one of many potential wildcards that could occur.
No, worst case is it happens during the middle of a heat wave and tens of thousands die in the big cities because they have no air conditioning, no water and no means of leaving the city.
Doesn't the tendency of an event recurring increase with the passage of time?
This is a common belief, but it is utterly wrong. Consider flipping a fair coin. The probability of getting heads is 1/2 always. If I got heads the last 100 flips, what's the chances of getting heads again? 1/2.
On the other hand, the probability of getting heads 100 times in a row is 1/2^100. Confusing these two probabilities is the basis of the Gambler's Fallacy.
However, there are some natural processes that fall subject to this reasoning. Take the earthquake example. Let's say that the chances of an earthquake happening increase as subterranean pressure increases. Let's say that everyday the subterranean pressure increases by some (small) random amount. In this situation the chance of an earthquake does get bigger everyday, but that's because there is something actively increasing the probability.
Compare with the earth being struck by a cataclysmic asteroid. In this case, there's no analogous process building up over time so it is fallacious to conclude that the chances are getting bigger every day that we don't get struck.
all of the naysayers seem to point out examples that mean absolutely nothing about what we are talking about here
1. "i live in a rural area, everything will be fine"
actually yes, you are right, i agree rural areas will be totally fine. now: tell us about major urban centers, with population densities intrinsically dependent upon regular power, that would experience serious problems
2. "we had a power outage, it wasn't that bad"
yeah: it lasted a few days. we're talking MONTHS here
3. "i come from a place with regular places intermittent power outages, we did ok"
yeah, and life adapts when thats the status quo. we are talking about a highly electricty dependent society, that has had regular pwoer for decades, suddenly without power FOR MONTHS
4. "you can get the transformers up quick, you can cannibalize 2 or 3 and get one working ok"
all the transformers would be destroyed in exactly the same way. there is no backup supply on hand, adequate supply and distribution and installation would take weeks, months
its not the lack of power that is the issue. the issue is the suddenness, the long time period, and the effect on high density areas that have grown accustomed to reliable electrity. so a lot of the naysayers here don't seem to attack the real issue here, and teach us nothing, not a damn thing, about what it would be like for that society which has depended upon regular power for decades, to suddenly not have it at all
and then there is the idea this is all some sort of hollywood movie driven hysterical fearmongering. what? no one is pissing in their pants. its a valid concern, and the fix is not very difficult, and people are talking about it calmly. we cant' do that without being accused of screaming "THINK OF THE CHILDREN!" really?
its worth discussing rationally and doing something about it? we have to do nothing about this problem because you think this is false alarmism? well, false alarmism is a real problem in this world. so is a false sense of complacency. it depends upon the nature of the problem. here we are talking about an issue which is relatively easy to fix, a valid long term concern, compared to threats like religious extremism or an asteroid the size of a football field. so why not discuss it rationally and go fix it?
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
hit that critter at the right time with that taser, and you could kill it AND COOK IT, all at the same time
this is helpful with squeamish city dwellers who will be killing their first wild game for food. just tell them its god's microwave oven at work
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
Well thanks for ruining my happy thoughts. I was sitting here picturing thousands upon thousands of iPods (and users) bursting into flame.
You're assuming that they're going to fail in random ways. What's being described is that every one of them fails in exactly the same way -- which means you can't cobble together a single working one from multiple failed ones.
You're right in that things likely won't fail nearly as badly as they make it out to be -- I know the power companies have the ability to do rolling brownouts, as we used to regularly have them when I lived in DC ... it's only a small step to rolling backouts like you describe after that.
What is going to happen is that people are going to have a horrible jolt to their comfort levels. We'll move from TV to battery powered radios, and have to give up our dependance on pre-made frozen meals. Other than the medical issues described, it's not going to kill us unless we refuse to adapt. We'll probably lose more to riots and looting than directly caused reasons.
Build it, and they will come^Hplain.
... We have one (1) data point for solar flares of this magnitude. We cannot make *any* meaningful statements about frequency.
Not true. Even ZERO observations during a period of time provide information about frequency of occurrence: i.e. it sets a probabilistic lower bound on the frequency of the (hypothesized) event.
One observation during the less than 170 years when this could be detected gives this, roughly speaking, 10-1 odds against being an only one-in-1700 year event.
Might it be an only one-in-a-millenium event? Sure. But the odds are rather against that being the case.
Starships were meant to fly, Hands up and touch the sky - Nicky Minaj
Evolution?
Peter predicted that you would "deliberately forget" creation 2000 years ago...
you are clearly ignorant. this is not meant as a throwaway insult, but a qualitative judgment of your words on the subject matter
here's some intellectual charity:
http://micro.magnet.fsu.edu/electromag/java/faraday2/
start there. follow the links. read. educate yourself
THEN comment
the issue here has absolutely nothing to do with static electricty, or small electronics. it has to do with electromagnetic induction across long powerlines
why is it we have to live in a world where the dumbest amongst us are usually also the loudest?
intellectual property law is philosophically incoherent. it is your moral duty to ignore it or sabotage it
The excellent BBC documentary series Connections begins with the scenario of a prolonged power grid failure, and traces the consequences in NYC.
Food becomes the major issue fairly quickly, due to the just-in-time economy of the cities. After a month, people are getting fairly desperate, and flooding out into the countryside, where considerable social churn ensues.
How many of you have two months worth of food on hand? Few things skew human behaviour more quickly than hunger.
Food security is the basis of sound social planning, and the weak point of any large city.
Damn those pesky terrorists
Damn, what is wrong with you? A well-articulated explanation of probability. I must have navigated away from Slashdot briefly.
I'm Peggy.
A hundred bucks locally to me would get you a 50 lb sack of rice, similar some sort of quantity beans. Another hundred would buy a lot of canned food on sale. Water is critical though, relying on that tap for the only source is real iffy. Here we have our own well, plus stored water in a few water barrels, plus a local stream and quite large pond. To go with this good quality water filters, in our case, berkeys. And yes, rotate the stock. The saying we use is "store what you eat, eat what you store".
I've been into this sort of thing ever since the cuban missile crisis and then a few years later a whopper big snowstorm that shut everything down for more than two weeks where I was. And when I mean shutdown, even the largest snowplows got bogged down, 4 feet of snow in 24 hours, then drifting for a few days. And very few snowmobiles back then either. It makes an impression on you what happens once normal supply is borked.
Ok Mr. sun, bring it on. I can network _and_ blacksmith. :D
-ellie
I think instead of neolithic, which refers to the late stone age and the rise of farming, you meant the paleolithic. Humans are biologically adapted to the paleolithic, I suggest, since it's 99% of our history.
One marker of the onset of farming is the increased average workload. That's the loss of eden: when the hunting is good, the weather cooperative, the food is plentiful and life is easy. Farming depletes bioproductivity, through deforestation and loss of topsoil and displacing wildlife; constant labour is the trade-off for year-round food security.
Longevity estimates of paleolithic life are skewed by risks. If one survived birth (or giving birth), occasional famine (remember longevity's links to low calories), smilodons, malaria or worms or massive infection, being poked by competitors' spears, and genetic diseases, then chances were you were one tough, clever piece of meat, and lasted as long as we do. Certainly the typical diet was healthier in some respects, just not as reliable.
Damn those pesky terrorists
Try reading the article. We wouldn't be just losing a few transformers, we'd be losing all of them (of a certain, critical type). There aren't enough spares to replace all of them at once so we couldn't quickly get the grid back up.
Unlike asteroids, this seems like a very solvable problem from a technical point of view but very difficult from a political one. The solution would be to replace the aging early warning satellite (ACE) with at least two satellites designed specifically to detect a storm like this. Procedures would have to be put in place to pass this warning to power companies around the world extremely quickly because it would take about as much time for them to disconnect their transformers as the warning allows (15 minutes).
This wouldn't require replacing the transformers around the world but simply putting up a couple of satellites and improving communication between the satellite operators (probably NASA) and the power companies. While this would cost some money, it wouldn't cost nearly as much as other low frequency disaster mitigation projects (like dikes to protect New Orleans from cat 5 storms) and would be potentially very effective.
Frankly I'd be all in favor of putting satellites like this up. While this wouldn't solve the problem of existing satellites in orbit that could potentially get fried by a storm like this it could greatly aid power companies in preventing potentially devastating infrastructure damage.
To me this is an ideal use of NASA's resources, using a portion of their budget to help prevent potentially enormously expensive damage to equipment around the world and potentially saving many lives in the process.
I think you're underestimating things. In my worst case scenario this event destroys the power grid for the entire US during the middle of a record heat wave.
1)No, I don't think they would have means of leaving. First, where would they go? There's no power anywhere. People by and large will stay where they think they are safe until desperation drags them out of their homes. The government will also initially tell people to stay calm and stay in their homes.
2)No, there is not enough busing capacity to deal with a mass exodus of every major city in the US. It would be an impossible undertaking during a normal day. There will not be the capacity for it within days of the power grid being destroyed let alone a week afterward. Where would these people go? There's no place for them.
3)No, cities by and large are not prepared for the grid being destroyed. That was the point of the article. There aren't enough generators warehoused right now to do what you're suggesting. The power grid was just destroyed. In every US city.
Even during optimal times a major heat wave can cause hundreds of deaths in large cities in FIRST world nations. Without air conditioning this will be much worse. Modern buildings are not designed to be occupied without working central air. Without an adequate water supply you will not last 3 days. Third world countries suffer just as much. We just don't hear about it.
Regarding gasoline and generators, in a worst case scenario there will be zero refining because the power grid is dead. I'd like to think they'd be brought back online quickly, but how long do you think it will take to get all of them operational again? Days? Weeks? Gasoline supplies will be extremely tight very quickly.
The local government may be able to bring in a few generators to make water flow for a while, but I don't think they'll be able to sustain that across an entire metropolitan area. We don't have enough generators warehoused to supply one city with enough to provide all the basic services. Every city will need them.
Unless this event lasts long enough to fry the entire hemisphere, diesel will have some limited availability(some amounts of it are brought in pre-refined). So yes, some amounts of trucking will be available.
However, there will be enough bottled water to last days. I doubt there is enough warehoused bottled water in the country right now to keep a single major metro area in drinking water for a week. And we're talking about every single one in the US.
Heat stroke kills. Within days there will be no major medical center left with adequate supplies or generator power. So people that would normally survive a heat stroke will die.
I think you're really underestimating the impact of the destruction of the electrical grid of the US and are willfully ignoring the cascade effect that such an event will have.
I'm merely stating that I think tens of thousands of people will die because of lack of AC and water. I'm not estimating the numbers that will die due to fire, starvation and civil unrest. Those numbers will be much higher.
Actually, you forgot the event of 1908 in Siberia, which, if it had landed 4 hours later would have taken out St. Petersburg, and the fall of 3000 meteorites in Normandy in 1803, both of which were only a small part of a sequence of cometary near misses that goes back at least to the dendrochronological minimum of 4375 BC. It's really quite amazing we're still here at all:
http://neros.lordbalto.com/ChapterEight.htm
Hic iacet Arthurus, rex quondam rexque futurus.