We've all seen the various sign-wielding, oft-toothless and wild-eyed folks bemoaning that doomsday is at hand, chuckling to ourselves as we hustle and bustle on to our cubicles or to meet friends for a frothy beverage. "Silly fella," we think to ourselves, secure in our presumption that the apocalypse most assuredly isn't nigh, "he must be totally bonkers."

Don't be too sure.

While the old "trumpet sounding/floating away" theory may or may not pan out, nature has a few potential surprises in store that are more Four Horsemen than Pacific Rim. We sat down with Dan Martin, author of Apocalypse: The Book and survival website DIY Sufficient, to get his professional opinion on each of these possible scenarios, including having him assign a risk factor of 1 (unlikely) to 10 (it's gonna happen, no doubt about it) to each.

Global Warming / Climate Change / New Ice Age

Martin: The one in Iceland left a ring of ash that circled the globe for a couple of weeks. The scenario of blacking out the sun and changing the climate, or killing off all the plant life though... It would have to be pretty extreme. planes were grounded from the ash produced by a volcano in Iceland? Well, in the spirit of global destruction synergy, it appears that the melting of the glaciers is decreasing pressure on the volcanoes there, which could lead to a champagne-cork like effect.The one in Iceland left a ring of ash that circled the globe for a couple of weeks. The scenario of blacking out the sun and changing the climate, or killing off all the plant life though... It would have to be pretty extreme.

Risk Factor: I'd rank this one pretty low, like a 2 or a 3.

Global Pandemic

There's been a rush of movies dealing with this possibility, from it fueling a zombie apocalypse to simply wiping out more than half of the world's population with some as-yet noticed virulent disease. From antibiotic-resistant SARS to ebola to the black plague and even common cold, microscopic monsters have long been a bane to our species. Some scientists see the likelihood of something along these lines as increasing by the day, as we travel more and animal diseases, such as H1N1, make the jump from critters to us.

Martin: We have had hundreds of thousands of viruses that could really destroy our populations. The black plague covered the planet in months, and that was before we had air travel. These major hubs like NYC, and Hawaii, Houston, these are hotspots that just move viruses so quickly across the planet.

I read a study saying that our smartphones, have more bacteria and germs and viruses on them than a public toilet. At first I though, 'that's ridiculous', but then once I read the study I realized you take this object, with little holes all over it, and put it in a dark warm spot, in our pocket, we never clean it, put it to our mouths, spray bacteria all over it... Then you compare it to a public toilet, which is smooth porcelain and cleaned regularly... Not to mention every dollar bill we touch, nobody washes dollar bills!

Risk factor: I would say definitely a ten.

Social and Economic Collapse

While normally thought of as a symptom of any of the above disasters, what if, say, a group of hackers unite and bring the stock markets or power grid down? Chaos would ensue. While many industrialized nations may try to order martial law to keep the peace, this could only go on so long. Are you prepared for a world without order?

Martin: The devastation it might cause? We're not really sure yet, it depends when it happens. I remember the cyber attack that we (the U.S.) carried out on (North Iran). The mission was code named "Olympic Games" there was a nuclear facility in Iran attacked including a worm named Stuxnet. Which allegedly led to at least 1,000 centrifuges at a facility for enriching uranium to break down and be destroyed. The technology is advancing, and the money that we're putting into defense of Internet and virus attacks is migrating so fast that we can secure ourselves from these attacks quickly. On the other hand, because the advancement of the Internet and the advancement of technology is happening so fast that we can send these viruses and overcome security... It's a vicious cycle.

Risk factor: The likelihood of this happening? 9, 10.

Magnetic Pole Shift

Want some more? Well, how about a magnetic pole shift? 'Cause that's happening now, with magnetic north (and thus the direction of compasses) changing by up to 40 miles a year, and getting faster all the time.

Martin: The thing we have to watch for is the physical core switch of our axis. It's like when you put two positive magnets together, and you push them together, they violently flip around, and that happens kind of for the same reason. Our sheet of earth is floating on magma, and the plates move around and when the magma and core gets highly active because of the magnetics, it moves those plates and switches the earth around a lot, and the physical sheet of earth could switch or move around, or flip to the other side, and that could be 100 percent death to everybody. There's no way of getting out from under that. The only place you'd be safe is on the space station.

Risk Factor: Will it happen in our lifetime? Probably not, I would put that pretty low. 1 or 2.

Space

These are just here on earth, but what about something coming from the vastness of this space that we're floating like a speck of dust in? The potential for sudden death is always just around the corner from a variety of subjects that sound like the basis for a Bruce Willis sci-fi movie. Getting fried by a gamma ray burst would sure suck, and it's really only a matter of time before one of the gazillions of rocks hurtling through space scores a bigger hit — smaller ones happen all the time. Of course, there's always the possibility of getting swallowed by a black hole, too.

Martin: Asteroids. They land every year. I'm talking about asteroids that would take out a city. If an asteroid hit around Pennsylvania, it would wipe out the entire east coast, and that would have political and social repercussions around the world. You'd have to deal with an electromagnetic pulse, it would shut down all electricity across the whole western side of the United States, and an EMP doesn't just shut it off, it destroys it. It melts anything in it, any copper, anything that's conductive, it just melts it. You'd need a whole new infrastructure, new electrical lines, all the stuff in warehouses to roll out would be ruined, and you'd have to manufacture new stuff, but all the equipment would be ruined, so you'd have to manufacture new equipment, it just would set us back so far.

Risk factor: Pretty simple I would say, probably a 9 or an 8.

Man-Made Disaster

Of course we could just wind up doing ourselves in, either with the ubiquitous threat of nuclear destruction, or how about being overtaken by a grey goo created by self-replicating, unstoppable nano-bots? Sound crazy? Not to Prince Charles it doesn't.

Martin: To make a long story short, the problem with nanotechnology right now is that we're such in an infant state, this is exactly the time when mistakes occur and accidents happen. So you build a nano-bot, to do some innocent medical job, and we don't understand completely what we're telling it to do, and it just goes awry, the chances of it doing what's good are very low compared to the chances of it doing bad or a mistake happening. As far as nuclear, in the last two years, there's been ten. They call them "red button pushes", where we've armed our nuclear missiles because of mistakes. There's been more chance of nuclear apocalypse in the last two years, than there ever was in the whole Cold War.

Risk factor: Ten, absolutely.

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