Tsunami: the road to extinction

As the death toll keeps rising, it seems certain that the tsunami on December 26 killed more than the 140,000 who died at Hiroshima. A search for culprits has begun, but is misdirected. The real culprit is nature.

Ecologists have created the myth that nature represents a harmonious equilibrium threatened by human excesses. In fact nature\’s apparent harmony is a short-term illusion between cataclysms. Bill Bryson\’s \”A Short History of Nearly Everything\” reveals enough natural dangers to make man\’s survival so far seem a miracle.

Nature\’s vagaries have made extinct 99.99% of the 30 billion species created since life began. The Ordovician and Devonian extinctions wiped out 80-85% of all living species. The Permian extinction (245 m. years ago) wiped out 95%. Humans have done their bit too. Estimates of man-made extinctions range from two per month to 600 per week. Yet even the high figure pales besides nature\’s own extinctions. Humans have survived only by squeezing through a series of closing doors over millenia.

The last 2.5 million years witnessed 17 major ice ages, all killers. The periods between ice ages represented global global warming, and were (ironically) saviours. Maybe greenhouse emissions will cause calamitous weather changes in a century. But a greater disaster by far will be the next ice age. The interval between ice ages has been as short as 8,000 years. The last ice age was 10,000 years ago. A new one is due.

We worry that greenhouse gases could raise the earth\’s temperature by 3 degrees in the next century. But nature itself creates more dramatic warmings. Ice cores fromn Greenland reveal episodes when temperatures shot up by 15 degrees in ten years.

Since 1850, humans have lofted 7 billion tonnes/year of carbon into the atmosphere. But nature belches 30 times more through volcanoes and decaying vegetation. One single volcanic explosion at Krakatoa, Indonesia, in 1883 threw more particulate matter into the atmosphere than all the industrial smoke ever generated by humans, and created tsunamis that reached Britain.

A volcanic eruption at Sumbawa, Indonesia, in 1815 was equivalent to 60,000 Hiroshima bombs. Thirty six cubic miles of dust and ash cloaked the sun globally. Summer failed to warm the earth as usual, leading to the worst year in history for agriculture. Crops failed everywhere, causing famines and epidemics.

Even bigger was the Toba volcanic eruption 74,000 years ago in Sumatra, which led to at least six years of \”volcanic winter\”. This is believed by scientists to have brought humans to the verge of extinction: maybe only a few thousand of us survived.

Supervolcanos like Yellowstone Park,USA, will one day wipe us out. Yellowstone\’s geysers are a tourist attraction, caused by boiling rock underground. These create 1,260 earthquakes a year, most too small to be felt. Yellowstone is the crater of an old supervolcano that has exploded periodically every 600,000 years or so. The last explosion was 630,000 years ago. The next is due.

Germs are part and parcel of the environment. We like to think that we have conquered most diseases. But we have not conquered viruses. One single viral influenza epidemic in 1918 killed 50-100 million people. Antibiotics once protected us against bacteria. But rising bacterial resistance to antibiotics means that only one drug, vancomymicin, is effective against serious staphylococcal infections. And now hospitals the world over have reported strains resistant even to vancomycin.

Worse could be a meteor or comet crashing into the earth. One such meteor, the KT meteor, caused the exctinction of the dinosaurs. The number of asteroids crossing the earth\’s orbit could run into millions: it is only a matter of time before the next disaster. Twice in the 1990s an asteroid passed within just 100,000 miles of the earth. In cosmic terms, this was the equivalent of a bullet passing through your sleeve without touching your arm. Next time we may not be so lucky.

The conclusion is sobering. Humans do indeed pose a threat to nature. But this is nothing compared with the threat that nature poses to humans. With effort, we can check our own excesses. We cannot check nature\’s. Nature will wipe us out one day, maybe sooner than any of us dares think.

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