Biodiversity & the Sixth Extinction
Author: Dr John M Anderson ~ Gondwana Alive
( Article Type: Overview )
'The SIXTH GREAT extinction spasm of life is upon us, grace of mankind’ – Wilson (1992)
‘For each of the Big Five [extinctions] there are theories of what caused them, some are compelling, but none proven. For the sixth extinction, however, we do know the culprit. We are.’ – Leakey & Lewin (1995)
‘Imagine an asteroid the diameter of central Sydney slamming into the Earth. We humans are that asteroid … We are forging the Sixth Global Extinction.’ – Anderson (1999)
Ask the first 100 persons you encounter at your local shopping mall, on a Saturday morning in Pretoria, what this ‘Sixth Extinction’ might be, and the chances are 99 of them will shrug their shoulders in vacant response. Do the same in London or Tokyo and the response will be the same. That is our greatest problem and its greatest cause. Democracy is arguably the smartest form of government humanity has devised till now, yet almost no member of these spreading democracies has any notion of the most overwhelming, indeed catastrophic, threat to their existence. All humanity, past and present, are the cause of the Extinction, yet virtually all of humanity remains unaware of its throttling embrace.
So what is the Sixth Extinction, when did it begin, what is its extent, and what is its cause? How long has the term been around?
Over the past 500 million years, since complex life colonised the seas, then the continents, there have been five major global extinction events. For one or other reason – asteroid hits, vast volcanic activity, global CO2 poisoning, abrupt climatic change, oceanic stagnation – perhaps 90% of all life forms (species) have gone extinct in a geological moment. The last such event, the fifth, was when the dinosaurs died out 65 million years ago.
The Sixth Extinction of life is now ‘upon us’ – it is of our time. We are in its remorseless grip. It is not hovering out there on the horizon threatening: it is happening. It began around 140 000 years ago and has been increasing in magnitude, exponentially, ever since. We are within the tsunami, perhaps halfway overwhelmed. And we, every one of us – through our ignorance, our divisions, our political, philosophical and economic systems, our science and industry, our inventive genius and our exploding population – are its cause.
The notion of asteroids hitting the Earth and causing mass global extinctions was first raised by Luis Alvarez and colleagues in Science in 1980. It ignited something of a revolution in thinking about the history of life. Through the rest of the 1980s, extinctions and their causes became very lively science. The previous Big Five extinctions were dissected and debated at great length; and slowly the Sixth – ours – has become more tangibly defined. Only within the last decade, with the pair of books by Edward O. Wilson, The Diversity of Life (1992) and Richard Leakey The Sixth Extinction: Biodiversity and its Survival (1995), has the term the Sixth Extinction begun to emerge in academic circles. It hasn’t yet surfaced in meaningful measure beyond.
The exponentially increasing Sixth Extinction can be shown pretty convincingly to parallel humankind’s headlong expansion in numbers from literally 1 of a kind some 140 000 years back to over six billion individuals today. And this population explosion can be inseparably tied to three successive, seminal communication revolutions: language, writing and printing. It is ironic that it is our sheer genius that is propelling us towards our pending demise.
Causing the Extinction
1. Mitochondrial Eve and the origin of language (hunter-gatherers, the first phase of extinction)
- Global population – from 1 individual to 5 million persons
- Centre of dispersal – eastern or southern Africa
Somewhere in Africa south of the Sahara, Mitochondrial Eve and her kin, around 140 000BP, developed some elemental ascendancy over their fellows. It was a dramatic time in Earth history. A huge swing of some 10 degrees C in global climate, from peak glacial to peak interglacial, occurred between 145 000 and 135 000BP. What adaptation other than a quantum leap forward in the capacity to use language could have conferred on her clan such titanic advantage that they weathered the climate change, populated the region, the continent and finally the world to the total exclusion of all less endowed archaic Homo sapiens rivals, including Homo neanderthalensis. Within 130 000 years Eve’s descendents had colonised virtually all the world and reached saturation population for hunter-gatherers of perhaps 5 million.
As we moved further afield from our mother continent, Africa, we became more lethally feral, not unlike cats or mice on Marion Island or rabbits criss-crossing Australia. On reaching Australia (>62 000BP), the Americas (ca 12 000), Madagascar (ca 1 500BP) and New Zealand (ca 1 000BP), we hunted to extinction the prolific megafauna in our path: 80–90% of the species of larger mammals and flightless land birds succumbed.
2. Invention of writing (farmers and city dwellers, the 2nd phase of extinction)
- Global population – from 5 million to 500 million persons
- Centre of dispersal – Middle East, Persia; ca 5 500 BP
Between the Tigris and Euphrates Rivers, in modern day Iraq, some 5 500 BP, the curtain between prehistory and history was drawn aside: writing was invented. The first texts, stylized picture images were etched into wet clay tablets. They had simple pragmatic purpose, reflecting no great mystical portent or dynastic ego, but rather a tally of cattle or sacks of grain. It soon gave rise to a succession of civilizations in the Middle East with their legal codes, sophisticated farming records, administrative bureaucracy, political hierarchies, enabled by the wedge-shaped characters of cuneiform and the pictorial symbols of hieroglyphics. Writing was the key to advanced agriculture, city-states, nations and civilizations; and a new quantum in population increase.
Over the following 5 000 years, humanity raced to a global population of 500 million – 100 times that of their prehistoric/ pre-writing forebears. Yet that was the merest hint of what was to come. With farming, cities and roads, humankind set alight the second phase of extinction: habitat transformation. Floral diversity – species, communities, ecozones – now became severely hit. Primary nature gave way to monoculture, to domestication.
3. Invention of the printing press (scientific and industrial revolutions, the third phase of extinction)
- Global population – 500 million to 5 000 million
- Centre of dispersal – Western Europe, Germany; 1454AD
In Mainz, Germany, in 1454AD, Johan Gutenburg invented the printing press – or rather he was the first to develop and combine movable type, an oil-based printing ink and a suitable press into an effective system for the mass production of books and other documents. It was the mother of revolutions. It spawned the age of global exploration, it ignited Humanism and the Reformation, it made possible the Scientific Revolution followed by the Industrial Revolution and ultimately the Medical Revolution and the Electronics Revolution. In 500 years, Eve’s human family recolonised the world, this time in ships, trains, cars and airplanes, and exploded in numbers by a further 10-fold to over 5 billion – and decimated primary nature in the process. Gutenburg could not have suspected what he was unleashing. In direct proportion to the sophistication of our discoveries, inventions and growth of knowledge, pristine nature has been erased around us – like penicillin’s effect on mould. We have already eliminated 70% of the world’s most diverse hotspots and 50% of the tropical rainforests.
Stemming the Exctinction
4. The electronics revolution (World Wide Web)
- Global population – 5 000 000 to 6 000 000 million
- Centre of dispersal – Global; 1990s
In Cambridge, England, in 1897, Sir Joseph John Thompson discovered the electron, opening up the astonishing new world of subatomic particles and providing a basis for understanding electricity. Within 50 years (1946) appeared ENIAC, the world’s first electronic calculating machine; and within 100 years (1991), the World Wide Web, fashioned by Tim Berners-Lee. Order immediately reshaped the chaos of cyberspace. In just five years, the 600,000 users of the internet had burgeoned to 40 million. By 1999, 150 million people logged on to the Internet weekly. Now, suddenly, our global family truly lives in a global village. We can use those uniquely human attributes – speech, language and writing – to communicate with each other anywhere, anytime, instantly.
With the world’s knowledge at our fingertips and linkable and accessible, we can negotiate a new balance of nature, we can negotiate cessation of our population explosion and of the Sixth Extinction. Whilst the first three communication revolutions spawned our explosive rise, the fourth can and must take us to a new century of understanding.
During this very early stage of the fourth communications revolution, we have a clear choice: we either allow the fourth and final phase of the extinction to blaze out of control and engulf us; or we unite as the one global family that we are and stem this extinction. I continue – in driving the Gondwana Alive initiative – in the firm conviction that we will take the second route. There could be no possible point otherwise. And the positive spin-off is prodigious.
GONDWANA ALIVE CORRIDORS
The Gondwana Alive Society together with the South African National Biodiversity Institute, the Council for Geoscience and Cambridge University Press are completing a book entitled 101 Strategies towards stemming the Sixth Extinction. We find the ‘Gondwana Alive Corridors’ to be the most holistically compelling of these strategies. It has the potential to persuade each one of us – in all circumstances and all walks of life – to adopt a new world view recognising that 'business as usual' is untenable, that it is indeed the cause of extinction with rapid global warming simply being the coup-de-grace. (See article in The Enviropaedia, 2004, pp 110–104.)