Biodiversity loss causes extinction.

Numerous scholars from various fields of science today are concerned with the ongoing collapse of biodiversity. The first Global Assessment of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES),1 published in 2019, estimates that:

The rate of global change in nature during the past 50 years is unprecedented in human history (…) Human actions threaten more species with global extinction now than ever before. (…) An average of around 25% of species in assessed animal and plant groups are threatened, suggesting that around 1 million species already face extinction, many within decades, unless action is taken to reduce the intensity of drivers of biodiversity loss.

Societies’ very survival depends on their ability to avert the impending threat of biological annihilation via the ongoing sixth mass extinction of species, triggered or intensified by the globalization of capitalism over the last 50 years. Sir Robert Watson, Chair of IPBES (2016), doesn’t mince his words to say what is at stake: “We are eroding the very foundations of our economies, livelihoods, food security, health and quality of life worldwide.” There is no hyperbole in the claim that the collapse of biodiversity and the acceleration of global warming, two processes that interact in synergy, entail an increasing risk of extinction for the Homo sapiens. As pointed out by Cristiana Paşca Palmer, Executive Secretary of the Convention on Biodiversity (2018), “I hope we aren’t the first species to document our own extinction.” Julia Marton-Lefèvre, former Director General of the International Union for Conservation of Nature (IUCN), reiterates this warning for the umpteenth time in a statement to delegations meeting at Rio+20 in 2012:

Sustainability is a matter of life and death for people on the planet. A sustainable future cannot be achieved without conserving biological diversity—animal and plant species, their habitats and their genes—not only for nature itself, but also for all 7 billion people who depend on it.

10.1 Defaunation and Biological Annihilation

Rodolfo Dirzo, Mauro Galetti, Ben Collen, and other co-authors of a review titled “Defaunation in the Anthropocene” (2014) conceptualize one of the central aspects of the current sixth mass extinction of species: the term defaunation is used to denote the loss of both species and populations of wildlife, as well as local declines in abundance of individuals. The defaunation process is in full swing:

In the past 500 years, humans have triggered a wave of extinction, threat, and local population declines that may be comparable in both rate and magnitude with the five previous mass extinctions of Earth’s history. Similar to other mass extinction events, the effects of this “sixth extinction wave” extend across taxonomic groups, but they are also selective, with some taxonomic groups and regions being particularly affected. (…) So profound is this problem that we have applied the term “defaunation” to describe it.

In a 2017 article, Gerardo Ceballos, Paul Ehrlich, and, again, Rodolfo Dirzo warn about the false impression that the threat of biological annihilation is not imminent:

The strong focus on species extinctions, a critical aspect of the contemporary pulse of biological extinction, leads to a common misimpression that Earth’s biota is not immediately threatened, just slowly entering an episode of major biodiversity loss. This view overlooks the current trends of population declines and extinctions. Using a sample of 27,600 terrestrial vertebrate species, and a more detailed analysis of 177 mammal species, we show the extremely high degree of population decay in vertebrates, even in common “species of low concern.” Dwindling population sizes and range shrinkages amount to a massive anthropogenic erosion of biodiversity and of the ecosystem services essential to civilization. This “biological annihilation” underlines the seriousness for humanity of Earth’s ongoing sixth mass extinction event.