Scientists see TEOTWAWKI as a relatively smaller episode that is amplified by human frailty
The End Of The World As We Know It -- TEOTWAWKI -- is littered with predictions that didn't quite pan out.
Just ask the folks who are still chewing through the food they stashed away at the time of the Killer Blob scare four years ago.
That was when doomsters predicted CERN physicists would reduce the Earth to goo when they switched on their new particle smasher.
In October, a German woman who feared the Earth would be sucked into oblivion in a black hole failed in her court bid to stop the work of the European Organisation for Nuclear Research (CERN).
Armageddon experts thus are cueing weary smiles for another non-TEOTWAWKI moment on December 21, supposedly named by the Mayan calendar as the Big One.
"One thing all apocalyptic predictions have in common is that they are false. They never happen," sighs Stephen O'Leary at the University of Southern California.
Even so, many hard-headed scientists take TEOTWAWKI seriously.
They see it in the context of a relatively smaller episode that is amplified by human frailty, and so becomes cataclysmic.
We have survived worse
In the worst scenarios, many millions could die, economies collapse and civilisations could retreat or die, even if the planet -- and humans as a species -- survived.
In 1918-1919 so-called Spanish flu, a new strain of influenza against which people had no immunity, killed between 20 and 50 million people, making it the deadliest disease of the 20th century. In rough terms, it was the equivalent of up to 200 million deaths today.
Diseases, natural disaster and cosmic threats
There was a near-miss in 1997, when H5N1 bird flu, a strain that kills up to 60 percent of those it infects, broke out in Hong Kong. The virus was stopped by a drastic cull of poultry. And in 2009, a new virus, H1N1 swine flu, turned out to be relatively harmless.
But virologists say we cannot dodge the bullet forever. Another highly virulent, novel strain, mixed by farm animals and transmitted to humans, is just a matter of time.
Another biggie is climate change.
Super-storm Sandy has prompted much hand-wringing about extreme weather events caused by man-made disruption to the climate system.
But many experts say the worst impacts of global warming will be progressive, not monster single events.
Some specialists foresee repeated droughts that hit the world's bread-basket regions, forcing up the price of cereals and millions of poor people into famine.
Then there is the threat from space rocks.
A familiar nightmare is of the rogue asteroid or comet that smacks into Earth, creating vast fires whose dust would rise into the stratosphere and linger there for years, cooling the planet and shrivelling the vegetation on which land life depends.
In such a way was ended the reign of the dinosaurs, 65 million years ago.
A US-led initiative is monitoring the skies for the biggest asteroids.
But less well-mapped are smaller ones, capable of wiping out a city or region. There are also comets that are undocumented because they return to our neighbourhood on a span of centuries.
In the Cold War, scientists feared a "nuclear winter" from an all-out war between the United States and the Soviet Union.
But recent calculations suggest this scenario could occur even from a limited nuclear exchange at regional level.
A study reported in Scientific American in 2009 found that fires from 100 Hiroshima-sized warheads detonated by India and Pakistan would generate at least five megatonnes of smoke.
"Within nine days the soot would extend around the globe," it said.
"After 49 days, the particles would blanket the inhabited Earth, blocking enough sunlight that skies would look overcast perpetually, everywhere."AFP