Evolution

And the ants will carry on.

Before we learned how to handle tools and fire and developed communal defense and thus became a force to be reckoned with on the savannah, there were hundreds, perhaps thousands of species who had a turn as "top of the food chain".

They all have one thing in common that makes them different from us. They all went extinct.

Oh, there's plenty of carnivores who fear nothing except us. Nearly all of them are alive because they either don't compete with us significantly, or they just weren't worth the bother to annihilate. Some, like most of the great cats, were able to hold their own until the last century.

But we're top dog. They all fear us.

But we only take up the last 1/10 % of earth's chronology when there was life. We're newcomers, and we haven't been around nearly as long as dinosaurs were. Thousands of species took a turn at the top, and all fell, sooner or later, usually sooner. Most have lasted longer than we have so far.

There were a lot of things that could wipe out the top species. Disease was common, and sometimes evolution popped up with an import from far away that was bigger and nastier, and took over, wiping out the indigenous critters.

But the leading reason for the top of the food chain to go extinct was some sort of disruption in the food chain itself. It could be something local; a five year drought, major floods, overgrazing.

Or it could be more widespread. The global climate changed. While the earth naturally goes through an irregular rhythm of heating and cooling, the climate changes that wiped out the top critters were usually something sudden and fairly dramatic. The best known event is the asteroid that smashed into what's now the Gulf of Mexico some 69 million years ago, causing an ice age and eliminating the dinosaurs. But such events have occurred dozens, perhaps hundreds of times.

It didn't have to be an asteroid or comet that caused it, either. Cataclysmic volcanic eruptions could effect climate change often enough to disrupt food chains world wide, eliminating those critters on the top rung. Humanity has had their own brush with such events. The Hekla 4 eruption caused a world wide ice age from 2354 BC to 2345 BC. In what is now Ireland, over 90% of the population died from famine. Earth faced catastrophic environmental dislocation at or around 1628 B.C., 1159 B.C., and A.D. 540. Records from those times, while understandably scarce, make it clear that world wide elimination of advanced cultures ensued.

Humans as a race survived, but their civilizations faced more difficulty. As a rule of thumb, the more elaborate and complex a civilization the more likely it was to vanish after several years of crop failures.

Irish peat bogs and tree rings tell the tale of several years of nothing but winter, and on the four events noted, three were caused by an event 12,000 miles away: massive volcanic eruptions, usually in what's now Indonesia. Krakatoa, which is still active, was responsible for two such, along with an eruption in the late 19th century that, comparatively small, affected climate around the world for several years.

Fortunately, we're talking about cataclysmic events, volcanic shots that very literally could be heard around the world. They don't occur often.

But the simple, primitive tribal societies were largely unaffected. They had shortages and dislocations, to be sure – berries were scant, hunting was poor. But it was the civilizations advanced enough to have cities that suffered the most. They were likely to fall, and while some struggled back after a century or two, most became footnotes, scraps of grandeur that fell to barbarian hordes.

The higher up the food chain an animal is, the more vulnerable it becomes to climate dislocations.

The more advanced a civilization is, the more vulnerable it is to falling in the event of such dislocations.

That brings us to America, the most advanced civilization on earth. And Global Warming, a phenomenon that is certain to bring climate dislocations, even if nobody knows what the exact nature is of the dislocations we will encounter.

It's said, with good reason, that no American city is more than three days from starvation. Stores, for sound business reasons, don't want too much inventory, and want perishables to be as fresh as possible, so they keep the stock on hand to a minimum. If you want to cause thousands of deaths and chaos, you don't bomb the city: you bomb the truck routes and railroad lines leading into the city.

It's all very organized and efficient and coordinated, and produces the best results for the least expense.

It's also terrifying how vulnerable it is.

The more complex something is, the easier it is to cause a catastrophic breakdown. The more moving parts, the more vital points, the more likely it is to fail.

Now, nobody is quite sure what the weather patterns are going to do as they change, but change they certainly will. Anybody who thinks it just means summers will be a little hotter, winters a little milder is living in a fool's paradise.

Climate is an oscillating system. The more energy fed into an oscillating system, the wider and wilder the oscillations. Only with something as complex as weather, the results won't be simple or linear. Climatologists in Britain are aware of this, and are warning their countrymen that global warming could result in glaciers in Scotland and hideously cold winters like the ones Ottawa Canada used to get, when the Gulf Stream abandons the British Isles. (To appreciate how far NORTH the British Isles are, spend a summer solstice in Scotland. It doesn't get fully dark during the five hour night.) Glaciers in Norway, a lesser beneficiary of the Gulf Stream, have been growing recently, even as glaciers everywhere else on earth shrink.

America already had some of the wildest and most variable weather on earth to begin with. We have immense ranges in temperature, blizzards, tornadoes, hurricanes, droughts, floods and thunderstorms. (The county I live in has wider ranges in temperature and precipitation than does all of Europe, but that's another story).

If our weather is wild and variable now, what's it going to be like when several billion joules of energy are added to the equation?

Not only will summers for some get hotter. Winters will be colder. Swamps will dessicate and vanish, leaving new fossils for whoever looks for them millions of years from now. Deserts will flood. Vast fertile plains will be blasted into sterile salt plains. New ones will eventually develop, but between now and then, it's gonna get sorta hungry around here.

The climate changes on its own, and we know that. But this will be forced change, accelerated change, change that will come so hard and so fast that the food chain will have trouble adapting. Crops will shrivel, and the animals that eat the crops will shrivel. It will be like we had a vast volcanic eruption.

Or got hit by an asteroid.

Eventually, crops will find new places to grow. But we might not be around to appreciate it by then. A civilization of several hundred million will be living in a world that can only feed one one thousandth that number, or less.

Ecologists call it "a die off". From the viewpoint of evolution, it's a good thing, since it eliminates the failed species and forces development of new ones, better adapted to cope with the new conditions.

One thing that human history teaches us is that when conditions get desperate enough, there will be a war. We'll convince ourselves that those lousy Mexicans are living off the fat of the land while our babies starve, and attack. More death, more destruction. Assuming we have any technology left, we'll then attack Canada to get those banana plantations they have hidden away on Baffin Island. (Oh, go look it up: they saw their first robin EVER last summer. Must have been one confused bird, since Baffin Island, the size of California, has no trees).

The complexity and technology of our society which makes us so strong also makes us vulnerable. Three hundred million Americans facing major disruptions in the food and water supply won't be a pretty sight. You'll be hearing a lot more about those quarter billion guns we have stashed away, I expect.

If any human societies are most likely to survive, it would be hunter gatherers, who can move on, and live comfortably with the minimum needed to stay alive. I doubt we can.

If global warming just sort of creeps up on us like it's been doing, and fifty years from now bored teenagers smirk condescendingly at old-timer's tales about snow in New England and a tropical state once known as Florida, we might do OK. Not great, but OK.

But some scientists worry that changes could be sudden, and catastrophic. Pacific storms just simply stop hitting the West Coast, and not only does the West die of thirst, but the plains no longer grow anything. In the meantime, hurricanes become a year ‘round phenomenon along the greatly reduced east coast, with winds of up to 250 miles an hour.

And if there is anybody who cares about the former greatness of America to bother studying our time, they'll despise us for the cavalier attitude we had toward global warming.

Thanks to the Internet, they'll even know exactly who to despise.