We have never been more secure.  We have never been more vulnerable.

Forgive the mangling of beginning of A Tale of Two Cities, but these sentiments are true.  The complexities of society and technology have made us safer than ever before from disease, starvation, and invasion by barbaric hordes.  At the same time, any complex system depends on so very many of its individual parts – working correctly – that a single minor malfunction can begin a chain reaction that cascades into catastrophe.

An example from biology should suffice.  Cutting a starfish in half does not kill it.  The creature is very simple, and both severed halves can each regenerate into a new, complete starfish.  But an elephant, a much larger and vastly more complex creature, can be killed by a single spear thrust to the heart.

Human societies are like that.  Primitive groups of nomads survived for millennia despite periods of natural catastrophes, because they had no single nerve center, no local vulnerability that could destroy all of them at once.  Even so, each nomadic group's survival depended on finding adequate food at least every few days, making each of them vulnerable to short-term famine, which could kill off any single group.

Agricultural societies were less vulnerable, because they did not have to find fresh food every day – but when crops did fail, an entire year's effort went for naught.  Even so, the trade-off was deemed worth it in the long run, and agricultural societies grew into industrial powerhouses, and then into the technological wizardry that today makes us comfortable and secure.

But we have become like the elephant.  Our size, power, and complexity have secured us from plagues and other misfortunes that have destroyed many primitive societies.  But we depend on numerous loci of function – think of them as vital organs, like heart and lungs.  Every once in a while, we are reminded of this fact.

For example, a team of snipers, shooting at inductive transformers in a power substation in California, came dangerously close to one of those critical organs in April of 2013.  Were such attacks to occur on a large scale, coordinated and simultaneous, the damage could have brought down the nation's power grid.  This one attack may have been a rehearsal.

Quoting from the report: 

A minute before a police car arrived, the shooters disappeared into the night.

To avoid a blackout, electric-grid officials rerouted power around the site and asked power plants in Silicon Valley to produce more electricity. But it took utility workers 27 days to make repairs and bring the substation back to life.

Another known threat to our survival is the possibility of a relatively simple EMP (electromagnetic pulse) attack.  Such an attack could, in one blinding flash, cripple our power grid, destroy communications, and burn out the electronics that make automobile engines work.  At least ten years might be required to restore essential system functions – but within a year of such an attack, it is estimated that ninety percent of Americans would die.  That sounds like fantasy, but without power, communications, and transportation, we would be thrust back into the technology of the 1800s, when an EMP (the Carrington Event) from a solar flare destroyed the entire telegraph system – which was the only electronic infrastructure technology we had at the time.  The Carrington event was not an attack from an enemy, but a natural solar storm of the sort that rarely reaches the Earth (but could again).

Were that to happen today, there would be no way to transport sufficient food into our major cities.  New York City, with its ten million inhabitants, contains only enough food at any given time to last for a few days, after which food riots and starvation would devastate the population.

How many of us can farm and hunt with enough expertise to survive for a year?  Millions of us require modern medical support, especially medications, to survive.  Few of us could survive for that long.

Another threat to our complex technology is man-made.  It is the cyber-attack on computers, which uses something called "ransomware," a computer program that can scramble the data on your computer – and on the government's computers – making those data unusable...unless one pays the ransom.  An enemy nation would likely not repair the damage, even if the ransom were paid.  A prime suspect in the recent worldwide attack is North Korea.

What such weaponized programs can do is give relatively primitive countries, such as North Korea or Iran, a more level playing field – or should we say battlefield – in any conflict with the United States and its allies.  We could be taken by surprise and find ourselves armed only with muskets (figuratively speaking) against an adversary that is much better at using muskets than we are.

This partly explains why the Navy still trains its officers in the use of sextants, a low-technology navigational device invented during the 18th century, which require no computerized communications.  If the satellite grid ever fails, nuclear-powered ships could otherwise be literally wandering the ocean with no precise idea of their location.

The United States government has spent many millions of dollars creating shelters for itself should a natural or manmade catastrophe cripple our nation's vital organs.  Although you paid for that shelter, you would be shot dead if, in an emergency, you tried to enter it.  The facility could sustain only a few hundred people.

Not you.

At my age, I am not a survivalist.  You should be thinking about becoming one.