Life on the Brink

Humanity’s extinction on the horizon.  This edition published by New English Library 1977.

Humanity’s extinction on the horizon. This edition published by New English Library 1977.

A few hundred humans cling desperately to life, the pathetic remnants of a race that once spread far and wide across the land.  Climate change, possibly accompanied by pandemic disease, has decimated the population and these remaining men and women await their fate.  Their survival hangs in the balance.

This is not speculative fiction, but something which actually happened somewhere between 195,000 and 123,000 years ago.  A glacial stage in the Earth’s history may have drastically reduced habitable land, and these few humans survived in coastal areas in central or southern Africa.  The human race was genuinely on the point of possible extinction.

The genetic structure of human populations as they are nowadays was formed during the Ice Ages, and analysing it can help our understanding of how the human race was affected during those periods of significant climatic change, as explained in The Genetic Legacy of the Quaternary Ice Ages (Nature, 22 June 2000) by Godfrey Hewitt of the School of Biological Sciences at the University of East Anglia.  That’s not to say that it’s entirely clear why any population decline may have occurred, but genetics do allow us to approximate when and where potential bottlenecks in the human population may have occurred.

In When the Sea Saved Humanity (Scientific American, August 2010), Curtis W Marean, professor at the School of Evolution and Social Change at Arizona State University, describes how close Homo sapiens came to being wiped out at that time, and it was just an abundance of shellfish and edible plants on the African coast that saw our ancestors through.  That, and their advanced cognitive abilities – they were smart enough to work out how to survive.

Science fiction has often portrayed a tiny remnant of the human race fighting for survival after some catastrophe.  Since the Second World War, this has usually (and not surprisingly) been described as due to the aftermath of nuclear war.  Classics such as John Wyndham’s The Chrysalids from 1955 give a sense of the desperation in our descendants’ attempts to beat the odds.

However, in his 1934 novel The Strange Invaders, Alun Llewellyn envisaged a future where the habitable areas of the Earth have diminished as a new Ice Age holds sway and the dwindling remnants of humanity are withdrawing into a primitive state.  His book can be read as something of a satire of the political situation at the time, but the threat of extinction as a result of encroaching climate change is a powerful image.  Sound familiar?  Humanity has been there before.

The climate of our Earth is still changing, and possibly at quite an alarming rate.  It’s a subject we look into in the latest edition of Odyssey, which has just been issued.  Although global warming is seen as the most likely outcome as things stand, there isn’t actually a consensus on whether it will prevent or trigger a new Ice Age in the long term.  Either way, though, no Ice Age will be occurring in the immediate future – at least in the next few years – and it’s highly unlikely that the human race will face total extinction as a result of current climate change.

The longer term is more dubious, though.  If the worst comes to the worst, hopefully humanity will be capable of overcoming the outcome of any future climatic disaster just as it did last time.  Even so, we may need to face the question of whether our descendants will prove as smart as our ancestors in managing to survive what the climate may throw at them.

Richard Hayes, Assistant Editor (Odyssey)

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