11.1 The most fundamental belief informing Man’s relationship with Nature is the idea that he has dominion over all the animals and can do with them as he sees fit. This is an attitude from the earliest history of mankind predating by far any philosophy or religion. It is the one belief that has been most resistant to change and still largely determines mans relationship with nature.

11.2 George Perkins Marsh drew attention 150 years ago to the consequences of this belief: the large scale and pervasive destruction that Man was inflicting upon the environment. 100 years later Rachel Carson drew the world’s attention to the invasive destruction of the environment at a microscopic level with synthetic chemicals. What is the scale of the human threat to the environment to which they both drew attention?

11.3 Yuval Noah Harari gives and indication in his “Brief History of Mankind” The journey of the first humans to Australia is one of the most important events in history, at least as important as Columbus’ journey to America or the Apollo 11 expedition to the moon. It was the first time any human had managed to leave the Afro-Asian ecological system. As they pushed on, they encountered a strange universe of unknown creatures that included a 200 kilogram, two metre kangaroo, and a marsupial lion, as massive as a modern tiger, that was the continent’s largest predator. The giant diprotodon, a two-and-a-half ton wombat, roamed the forest.

11.4 Within a few thousand years, virtually all of these giants vanished. Of the twenty-four Australian animal species weighing fifty kilograms or more, twenty-three became extinct. A large number of smaller species also disappeared. Food chains throughout the entire Australian eco-system were broken and rearranged.

11.5 Some scholars argue that this was the result of some kind of climate change. Perhaps. However, the giant diprotodon appeared in Australia more than 1.5 million years ago and successfully weathered 10 previous ice-ages the last of which had twin peaks at 70,000 and 15,000 years ago. Moreover there is no evidence of any significant disappearance of oceanic fauna 45,000 years ago.

11.6 Another possible explanation is human efficiency at exploiting the environment, not just by hunting and killing these large animals, faster than they could breed, but also by laying waste large tracts of impassable forest with fire to drive the animals out into the open. They killed the animals efficiently and they killed the animals’ environment most efficiently.

11.7 Climate change may have been the culprit for the next wave of extinction. Around 12,000 years ago global warming melted the ice and opened an easier passage from Siberia to Alaska and the rest of America. Within 2000 years humans already inhabited the most southern point in America, the island of Tierra del Fuego. When they first arrived into the plains of Canada and the western United States, they encountered mammoths and mastodons, rodents the size of bears, herds of horses and camels, oversized lions and dozens of large species the likes of which are completely unknown today, among them the fearsome sabre tooth cats and giant ground sloths that weighed up to eight tons and reached a height of six metres. South America hosted an even more exotic menagerie of large mammals, reptiles and birds. The Americas were a great laboratory of evolutionary experimentation, a place where animals unknown in Africa and Asia had evolved and thrived.

11.8  But no longer. Within 2000 years of the Sapiens’ arrival, most of these unique species were gone. According to current estimates, within that short interval, North America lost thirty-four out of its forty-seven genera of large mammals. South America lost fifty out of sixty. Thousands of species of smaller mammals, reptiles, birds and even insects and parasites also became extinct.

11.9  A similar fate befell the mammoth population of Wrangel Island in the Artic Ocean (200 kilometers north of the Siberian coast). Mammoths had flourished for millions of years over most of the northern hemisphere, but as Homo Sapiens spread – first over Eurasia and then over North America – the mammoths retreated. By 10,000 years ago the was not a single mammoth to be found in the world, except on a few remote Arctic islands, most conspicuously Wrangel. The mammoths of Wrangel continued to prosper for a few more millennia, then suddenly disappeared about 4,000 years ago, just when the first humans reached the island.

11.10 Climate change would have had to strike New Zealand quite selectively in similar fashion. The Maoris, New Zealand’s first Sapiens colonisers, reached the islands about 800 years ago. Within a couple of centuries, the majority of the local megafauna was extinct, along with 60 per cent of all bird species.

11.11  This ecological tragedy was restaged in miniature countless times after the Agricultural revolution. The archaeological record of island after island tells the same sad story. The tragedy opens with a scene showing a rich and varied population of large animals, without any trace of humans. In scene two, Sapiens appear, evidenced by a human bone, a spear point, or perhaps a potsherd. Scene three quickly follows, in which men and women occupy centre stage and most large animals, along with many smaller ones, are gone.

11.12 The elephant birds, and the giant lemurs, along with most of the other large animals of Madagascar, suddenly vanished about 1500 years ago – precisely when the first humans set foot on the island. In the Pacific Ocean, the main wave of extinction began in about 1500 BC, when Polynesian farmers settled the Solomon Islands, Fiji and New Caledonia. They killed off, directly or indirectly, hundreds of species of birds, insects, snails and other local inhabitants.

11.13  This First Wave extinction which accompanied the spread of the foragers, was followed by the Second Wave Extinction which accompanied the spread of the farmers, and gives us an important perspective on the Third Wave Extinction, which industrial activity is causing today. Long before the Industrial Revolution, Homo Sapiens held the record among all organisms for driving the most plant and animal species to their extinctions.

11.14  Richard Leakey wrote the first book entitled “Sixth Extinction” in 1991. In it he argues that the waves of extinction described above are but a precursor to today, where human-driven extinction is continuing and accelerating at alarming levels. “Humans endanger the existence of species in three principal ways. The first through direct exploitation. The second is the biological havoc wreaked by the introduction by humans of alien species to new ecosystems – a process made ever more frequent by modern global travel and global trade. The third, and by far the most important, is by the destruction and fragmentation of habitat.”

11.15  There are still a few surviving species of large animal that humans are consciously pursuing to extinction, such as whales, sharks, tuna and dolphin, but as a result of previous thoroughness the list is limited, and public awareness can be aroused to interfere with this process. However, far more species are threatened more or less unconsciously by introducing for instance, alien insects in crates of food from one continent to another. And most destructive of species is the collateral damage resulting from destroying huge tracts of forest, giving over vast areas to monocrops and converting countryside into cities, turning the oceans acidic, and pumping greenhouse gases into the atmosphere.

11.16  As previously mentioned the environmental movement was and is a battle for hearts and minds. Richard Leakey refers to this. “Just recently, however, a backlash has developed, with the doomsayers being accused of overstating their case or worse fabricating it. Articles have appeared in several periodicals, expressing skepticism of the alleged danger. An article titled “Extinction: are ecologists crying wolf?” was recently published in Science, for instance; and the 13 December 1993 issue of US news and world report ran ac cover story, titled “The Doomsday Myths”. These and other articles essentially suggest that although ecologists believe that many species are becoming extinct, or are about to become so, they don't actually know for sure.”

11.17  “The method by which ecologists calculate the fate of species in habitats that are reduced in size is based on island biogeography theory, which the Harvard biologists Robert MacArthur and Edward Wilson developed in 1963. Partly the outcome of empirical observation, partly mathematical treatment, the theory is the foundation of much of modern ecological thinking. ‘The larger the area the more the species’. MacArthur and Wilson saw this relationship wherever they looked, from the British Isles to Galapagos Islands to the archipelago of Indonesia. Armed with this tool, what can we say about the consequences of reducing tropical rainforests to 10 of their original extent? The arithmetical relationship based on the theory predicts some 50 % of species will go extinct.”

11.18  But the debate is fraught with uncertainty. “Critics not only doubt the validity of these predictions, but also challenge ecologists to produce hard evidence of an alarming level of human-caused extinctions today. It is true that because there has been no comprehensive, global survey, ecologists are unable to proffer such evidence in the form of a complete list of extinctions. But despite the lack of a comprehensive survey, there is a large body of isolated studies in many different habitats around the world. Dismissed by critics as “merely anecdotal” these studies collectively give more than enough reason for concern.”

11.19  “The documentation of known extinctions may seem to be the only was to demonstrate that we are in the midst of a biotic crisis, and this is what skeptics demand. After all, there can be no case for murder without a body.” The question is does one stand by and wait for a murder to be committed before taking preventative action? Leaky gives a pertinent example of the Heath Hen. “The bird’s range, remember, was huge and covered much of the eastern seaboard of the United States. Hunting and habitat destruction reduced the species’ number to fifty individuals in 1908, when a reserve was established to save it from extinction. Over the next two decades the population’s numbers began to rise robustly, but eventually the species did go extinct, through a combination of biblical calamities, including fire and pestilence. The point of the story is that once the heath hen population was reduced to small numbers, its eventual extinction was virtually assured.

11.20  Elizabeth Kolbert wrote the second book entitled “The sixth extinction” in 2014 and won the Pulitzer Prize for her efforts. Her book puts the sixth extinction in context of the five previous extinctions, the last of which was the most famous of them all - the end cretaceous extinction 65 million years ago, which ended in an instant ten of millions of years rule of the dinosaurs. She relates how it was only in 1991 that the final proof was found of a theory published in 1980 by Walter and Louis Alvarez - that the extinction was caused by a meteorite impact.

11.21  She continues to the age of Man, and travels the world to find more of what Richard Leaky described as ‘anecdotal evidence”. There is an epidemic of chytrid fungi currently in process of exterminating vast number of frogs, such that “Today amphibians enjoy the dubious distinction of being the world’s most endangered class of animals.” There is an epidemic of another fungus called Geomyces destructans killing vast numbers of bats in New England. These are topical examples of large scale extermination caused by importing alien species from one continent to a new one referred to by Leaky earlier. Many examples can be cited from recent history for instance the extermination of the American species of chestnut tree by yet another fungus Cryphonectria parasitica imported probably from Japan. This spreading of fungi, insects and plants across the world by trade and travel, or homogenization of species, Kolbert describes as the New Pangaea – from the time when all the earth’s landmass was one continent called Pangaea.

11.22  There is discussion of the acidification of the oceans, thanks to the fact that roughly one third of CO2 that humans have so far pumped into the air has been absorbed by oceans. This in turn threatens marine species on a vast scale, particularly calcifiers such as the barnacles, mussels and snails as well as plants such as calcifying seaweed.

11.23  Following up on Richard Leaky’s discussion of the relationship between area and biodiversity, and his comments about the lack of a comprehensive survey of extinctions, she visits reserve 1202 which is part of a whole archipelago of Amazonian islands, which collectively represent one of the world’s largest and longest running experiments, the Biological Dynamics of Forest Fragments Project – which has been called the most important ecological experiment ever done, and also records MacArthur and Wilson’s estimates of the current rate of extinction.

11.24 As Richard Leaky warns, "Homo sapiens might not only be the agent of the sixth extinction, but also risks being one of its victims"