Gloom and Doom?

Even when considering the subject matter of my last few columns, I was shocked to hear that a few acquaintances actually consider me to be a doomsayer and sometimes rumor monger! Moi!? Gloom and doom!? Purveyor of rumors!? Heaven forbid!! Why, I’m the friendliest, happy-go-luckiest, easy going guy you’d ever want to meet! Well, my wife does think I’m a bit grumpy and grouchy, somewhat cantankerous, totally pessimistic, and I imagine a bit paranoid as well (particularly when I’m thinking about Congress, the IRS, the UN, and al-Qaeda). It’s to be expected I guess, considering that during most of my working life I’ve probably seen nearly all the bad things that can happen to people, and few of the good ones. After all, people usually call the Fire Department when they’ve got a disaster in the making, not when they win the lottery. Besides, I write about national and international politics for the most part, and that means gloom and doom are pretty much the order of the day.

However, in the interest of keeping the peace among my acquaintances, I’ll pass on discussing our politicians and the mess they’ve gotten us into (only for the week you understand), and talk a bit about a few non-political threats instead. So, with a smile on my face I’ll ask, how could the world end? No, I’m not about to go running around in a hair shirt, ringing a bell, and wearing a sandwich board sign claiming that “the end is near”! The end might well be near for all I know, but somehow I rather doubt it.

Seriously though, what sort of disasters might befall our little blue marble floating around in space? And how might that impact the human race? I can think of a few ways the applecart might get upset… But before I start speaking about real possibilities, there are two currently popular “threats” that are not going to destroy the Earth and all its inhabitants. Those two are global warming and global cooling. Global warming could be a bad thing for people who live near the coast or on the desert, but we really need to remember that our planet has been much warmer throughout most of history, and it seems that life is still here (although I sometimes wonder about “intelligent life”). At the other extreme, a new ice age would probably curtail most human habitation of the northern latitudes, but the tropics would be pretty much the same as we see today. However, I expect there'd be a lot more vacation property for sale in Florida as the sea level drops. Right now we're in the later half of an interglacial period, so it's a reasonably safe bet that the glaciers will again be on the move, probably within the next 10,000 years or so. No matter what the climate does, and despite Al Gore, we can expect to see any number of species extinctions, as always happens during climatic shifts. A species become extinct when for one reason or another they are no longer able to survive changing conditions, and typically that happens within 10 million years of its first appearance. It’s also estimated that 99.9% of all species that have ever lived are now extinct.

On to more serious threats that really could cause the end of life on Earth…

The Earth is struck by asteroids and comets all the time. On January 3rd of this year a large meteor exploded in the air near Tok Alaska, severely rattling the local citizenry. A hundred years ago what was believed to be a small comet exploded in the air over Tunguska Siberia with the effects of a nearly 15 megaton blast. Fortunately these incidents occurred in remote areas, and there were no known human casualties. But scientists keep finding evidence of medium-sized impacts that caused regional devastation, one near New York around 300 B.C., another in eastern Canada about 11,000 B.C., and the famous Meteor Crater impact in Arizona around 50,000 years ago. Even larger asteroids have been credited with mass extinctions in Earths biological history. The end of the dinosaurs 65 million years ago is one, and the more devastating Permian-Triassic extinction event 251 million years ago in which some 80 percent of animal species vanished. It would take an asteroid the size of a small planet to really snuff out life on Earth, but nobody has noticed one of those heading our way… yet.

An alternate theory for the flat featureless Martian northern hemisphere is that huge lava flows simply erased any previous features. Similarly, there's some evidence that the dinosaurs on Earth were killed by enormous volcanic eruptions in what now is India, instead of by an asteroid, or maybe in addition to. Moderate volcanic eruptions stir up huge amounts of soot, ash, and dust, blocking sunlight and that does have climatic effects. The eruption of Mount Pinatubo in the Philippines measurably cooled the planet in 1991-92, as did Indonesia's Krakatoa eruption in 1883. Even worse was the Mt. Tambora eruption on Java in 1815, which cooled the Earth so much that Europeans called 1816 "the year without a summer". The Mount Toba super volcano in Sumatra erupted 75,000 years ago and cooled things down enough that most of Earth’s human population died, leaving just a few survivors to repopulate the world. Then we have the Yellowstone supervolcano which will probably wipe out almost everything between the Rockies and the Appalachians, again. Ahh… and it’s already overdue.

But even supervolcanos couldn’t end life on Earth. To do that we’d need something similar to the eruptions that created India's Deccan Traps, or the Siberian Traps in Russia. In both cases huge fissures opened up in the ground and oozed lava that spread hundreds of miles in all directions. They released enormous amounts of gases, smoke, and soot into the atmosphere, and those eruptions continued for tens of thousands of years. In Siberia, 3 million square miles were covered by layer after layer of lava. It doesn't take much imagination to conclude that an eruption event two or three times the magnitude of the Siberian one could end life on Earth.

Still, while life seems to be quite hard to eradicate, the Earth will certainly come to an end in about 5 or so billion years when it’s engulfed by our expanding sun. It’s a natural event, as stars expand into red giants near the end of their lifespan, leaving their planets little more that burnt-out cinders drifting in the void. Some calculations indicate we've only got a billion or so years left on this planet, which is rather gloomy in itself, since life in some form or other has been around the third rock from our sun for nearly 3.7 billion years.

On the more cheerful side, scientists of an advanced future civilization could simply move Earth to a safer orbit. If we haven’t already been swallowed by a wandering black hole.