Andreas Wilson-Späth
Our capacity for wilful self-destruction knows no bounds. Industrial civilisation’s disconnect from the natural world, the fabric of which is the basis of our continued existence as it provides us with the ‘services’ (fresh air, clean water, etc.) we need to survive, is baffling, especially from a species that is supposedly the only one capable of rational thought.
Nowhere is this more evident than in our ongoing extermination of the plant and animal species with which we co-inhabit the planet. Yes, new (and weird) species are still being discovered, but the rate at which we’re exterminating them far outstrips such finds. You may have heard people refer to this as a sixth mass extinction and the scientific evidence for such an event is mounting rapidly.
Geologists define mass extinctions as catastrophic, widespread and relatively rapid periods during which there is a dramatic decline both in the diversity (the number of species) and the abundance (the number of individuals) of life on earth.
There have been several such occurrences in the past, but five are typically singled out as major mass extinctions during which between 60 and 96% of all species alive in the oceans and on land at the time disappeared forever.
The idea of a sixth mass extinction, one precipitated by human activities, has been the subject of growing scientific attention. Last year, for instance, a report commissioned by the WWF estimated that mammal, bird, reptile, amphibian and fish populations worldwide decline in numbers by 52% between 1970 and 2010, predominantly as a result of habitat loss as well as hunting and fishing. South America, where numbers dropped by 83%, was the most affected continent.
A study published in May predicts that climate change alone will threaten the survival of as many as one in six species extant today, with South America again bearing the brunt of the impact.
During the same month, new research revealed that the rate at which vertebrate animals have been going extinct since the year 1500 is on par with, or significantly faster than, that during the mass extinction which famously wiped out the dinosaurs (with the exception of the birds) some 66 million years ago.
Now, a new study published in the peer-reviewed journal Science Advances has confirmed that even at an “extremely conservative” estimate, species are disappearing more quickly than during this event, that human activities are to blame and “that a sixth mass extinction is already under way”.
It’s well worth noting that most of these studies focus specifically on vertebrates, because their status is comparatively easy to evaluate. If invertebrates, which represent the vast majority of species, are taken into account, things look even worse as there has been a “dramatic underestimation of overall levels of extinction” and that “we may already have lost 7% (130,000 extinctions) of the species on earth”.
In the latest update of its Red List of Threatened Species, which includes assessments of 77 340 types of plants and animals, 22 784 of which are threatened with extinction, the International Union for the Conservation of Nature (IUCN) has added 14 species to the category of ‘Critically Endangered (Possibly Extinct)’. Among them are a Haitian tree, the West African subpopulation of the African lion, ten Madagascan orchids and two Balinese crabs. In addition, researchers have recently suggested that at least six of Africa’s vulture species should be included in the same category. Seven of them have experienced a precipitous 80% drop in numbers over three generations.
It’s time to stop ignoring the evidence. The major difference between the current extinction event and ones in the past is that it’s not caused by an asteroid impact or humongous volcanic eruptions, but by our activities alone.
You might counter that previous mass extinctions have always been followed by a resurgence and blossoming of life in which numerous brand new species evolved into a myriad of suddenly empty niches. But while this is correct, it’s not a particularly reassuring thought if we ourselves are among the species that are terminally removed from existence.
A much more rational – and human – response is this: we’re causing this disaster, but if we act now, we can still put an end to it.
I’ll leave you with the conclusion of the authors of the recent Science Advances paper mentioned above: “Averting a dramatic decay of biodiversity and the subsequent loss of ecosystem services is still possible through intensified conservation efforts, but that window of opportunity is rapidly closing”.
- Andreas is a freelance writer with a PhD in geochemistry. Follow him on Twitter: @Andreas_Spath