In the Midst of the Sixth Extinction

Bob Bates —

slide_1In May 2019, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES), an international panel of more than 450 scientists from 109 nations, unanimously reported that the status of life on planet Earth is in grave jeopardy. Drawing upon 15,000 documents compiled by global environmental researchers, the panel noted that species loss has accelerated at a rate of tens to hundreds of times faster than at anytime in the recent past. Thomas Loveyjoy of George Mason University, the “godfather” of biodiversity, said, “Humanity unwittingly is attempting to throttle the living planet and humanity’s own future. … The biological diversity of this planet has been really hammered and this is really our last chance to address all that.”

Robert Watson, who headed the 1500 page report, underscored the urgency for action, arguing that we “are indeed threatening the potential food security, water security, human health and social fabric” of humanity the world over. This has occurred mainly through five main developments:

Widespread urbanization and global agriculture that replaces forests and grasslands.

Worldwide human-induced climate change that alters the habitats of nearly all land and sea life forms.

Over-fishing the world’s oceans (currently one-third depleted).

Continued emission of pollutants into the air, water, and on land.

Introduction of invasive species that crowd out native plants and animals, including the decimating impacts of alien microbes, bacteria, and insects.

In summary, unprecedented acceleration of the interaction of climate change, habitat destruction, and species loss exacerbate the scope of environmental and evolutionary vulnerability. It is not as if these approaching realities have not been foreseen for decades or longer. Much science-based information has documented environmental and biological threats, largely due to human activities in the process of creating our modern civilization.

* * *

Elizabeth Kolbert

Around the time of the IPBES report, environmental scholar and writer Elizabeth Kolbert published an article in The New Yorker magazine that provides a staggering account of the stresses and strains on the earth. During just the past half-century, the human population has doubled, the global economy quadrupled, and worldwide trade grown tenfold. Kolbert urges us to be aware of and concerned about the IPBES’s conclusions. We have reached a point where the earth has endured significant alteration of three-quarters of its land (including unprecedented destruction of its forests), severe stresses of two-thirds of its ocean waters, destruction of four-fifths of its wetlands, and decimation of half of its coral reefs’ oceanic ecosystems. Ninety percent of all flowering plants and 75 percent of global food crops require pollination by insects, birds, and other creatures. However, many areas of the globe are experiencing marked declines in these species, largely due to the proliferation of chemicals used in food production.

Current trends in this comprehensive assault on the biosphere carry ominous consequences. The bottom line of the IPBES wake-up call is this: Timely internationally cooperative “transformational changes in the approaches to and processes of production and consumption of energy, food, feed, fibre, and water” are needed.

81HiLi7irkLKolbert’s book, The Sixth Extinction: An Unnatural History, published in 2014, was a Pulitzer Prize winner. In it she compares and contrasts known past ages of extinctions and evidence of ongoing acceleration of human-induced extinctions in our own age—dubbed the Anthropocene age. Her approach to a project of such vast scope, beyond researching the history of paleontology, was to accompany scientists on their field research. Viewing life on earth up close and personal alongside geologists, land and marine biologists, botanists and field ecologists, and scores of other researchers in and out of the lab, opened her eyes to nature’s micro- and macrocosms of living things, and the looming threats occurring all around us.

Paleontology is the branch of science dealing with forms of life that have existed in past geologic periods. Discoveries of remnant fossil forms inform us about past life on earth as far back as 550 million years. An estimated 25 percent of surviving species have adapted over this span, yielding multitudes of bacteria, plants, insects, fish, reptiles, birds, and mammals. Across these millions of years, paleontologists have discerned many occasions of notable extinctions, among them five major ones. The scale of time for these is staggering—at 450 million years (Ordovician), 375 million years (Devonian), 250 million years (Permian), 200 million tears (Triassic), and 66 million years (Cretaceous) ago.

Each of the first four major extinctions resulted from earth’s natural changes, with the fifth from a massive collision by a huge asteroid. What is different now is unnatural changes being foisted on the planet through human influences and impacts. According to Kolbert, “we are in the midst of the Sixth Extinction, this time caused solely by humanity’s transformation of the ecological landscape.” This disruption and destruction of earth’s natural systems places in jeopardy, at the top of the food chain, our very human existence. In tracing back earth’s history, Kolbert underscores common features among past extinctions, but also finds unprecedented higher rates and numbers of species loss in the current period.

Paleontologists have assembled extinction evidence through fossils and by analyzing core samples of land, ice, and ocean floor. Consensus is that extinctions of micro-sized creatures have repeatedly resulted from probable variations of earth’s naturally changing structures and compositions. These very small life forms failed to adapt and died off. In contrast, macro animals—very large ones—such as dinosaurs, mastodons, mammoths, and giant cats, gradually died out because their breeding pairs dwindled. Either harsh environmental stressors or increased over-hunting by primitive humans proved them unable to adequately reproduce, as their gestation periods were too long.

Generally, though, over millions of years nature’s ecosystems stabilize into enduring homeostasis. Such has been the case until the onset of the Industrial Age in the early nineteenth century and subsequent worldwide development and its impacts on natural resources—animal, vegetable, mineral—and the technological byproducts of materialism. Now, within the last 50 years, our planet is stressed in the many ways the IPBES report cites.

Carbon dioxide is the megaproblem. CO2 poses the double whammy of global warming and ocean acidification. This one-two punch is the one main fear Kolbert and the many scientists she encountered carry with them in their daily consciousness.

People the world over are by now familiar with increasingly destructive consequences of climate change, but steadily incremental aggravation to the acid composition of the oceans (70 percent of the globe’s surface) tends not to be common knowledge. Marine scientists alarmingly call ocean acidification global warming’s equally “evil twin.”

A property of CO2 is that it dissolves in water to form acid. The vast ocean waters are salt water—alkaline—and over the span of a half-billion years, life in the oceans has been at a stable alkaline-acid equilibrium. However, as atmospheric CO2 concentrations have increased (from 280 to 410 parts per million since the Industrial Age), so have the ocean waters’ absorption of CO2. The pH scale of acid-alkaline has measured about 8.2 for ages. It is now approaching 8.0, or 30 percent more acidic than a couple centuries ago. Marine life is an intertwined, complex, and often delicate food chain. As documented in the world’s waters by thousands of replicated studies, biologists bluntly conclude “acidification kills relentlessly.” Inevitably, when marine organisms are exposed to increasing acidification, they sustain damage, setting off literal chain reactions up and down the food chain.

coral reefsPerhaps the most representative illustration is what has been occurring with the ocean’s coral reefs. These amazing just-beneath-the-surface vast clusters of marine “cities” have formed dazzling frameworks of co-evolutionary ecosystems of symbiotic life, food, and shelter for untold millions of years. But just within the last 30 years, acidification has so devastated reefs that half oceanwide are already dead or dying. Scientists foresee a grim future for coral reefs and the myriad of teeming species inhabiting them.

* * *

In her prologue to The Sixth Extinction Elizabeth Colbert writes, “If it is a morbid topic, mass extinction is, well, massively so. It’s also a fascinating one … what’s being learned as well as the horror of it. My hope is that readers will come away with an appreciation of the truly extraordinary moment in which we live.”

In her final pages, she contemplates possibilities.

In an extinction event of our own making, what happens to us? … Will we, too, be eventually undone by our transformation of the ecological landscape? [Or will] human ingenuity outrun any disaster human ingenuity sets in motion? … Right now, in this amazing moment that to us counts as the present, we are deciding, without quite meaning to, which evolutionary pathways will remain open and which will be forever closed. No creature has ever managed this, and it will, unfortunately, be our most enduring legacy. The Sixth Extinction will continue to determine the course of life long after everything people have written and painted and built has been ground into dust.

Certainly humans can be destructive and shortsighted; they can also be forward-thinking and altruistic. Time and again, people have demonstrated that they care about what Rachel Carson [who brought public attention to insecticides in the 1960s] called “the problem of sharing our earth with other creatures,” that they’re willing to make sacrifices on those creatures’ behalf.

To one extent or another—though maybe following much grimness and extremes of distress, and suffering—humanity will survive. The unanswered questions right now are at what dear costs and results to whom?

4 thoughts on “In the Midst of the Sixth Extinction

  1. I have been following global warming crisis since the warnings began, I am 69 years old so I doubt U will see the worst of it. The last statement from Bill Nye the science guy was profanity laced which is out is out character for him. I hate to say this but in 2 more years it is irreversible. Yes, the weather is getting bad but the greedy bastards will destroy the world along with us. Maybe it will take the beginning of a global crisis to snap everybody out of this atate of denial. Why not post on Facebook or Twitter?


  2. Gary, just how close to a “global crisis” do you think we are? The numbers, percentages, and proliferation that IPBES, past and continuing global warming and climate change assessments—largely unabated and apparently unleashed on courses of tipping points and irreversibility—rather convincingly indicate, as Kolbert says, that we are already AMIDST multiple trajectories to global disaster on many fronts. Is the human species really capable of ingenuity sufficient to markedly reversing these? And how much will humans’ “willful ignorance” and preferring to live in material abundance rather than recognizing how destructive their lifestyles are now, not being willing to make sacrifices for greater—and more vital—causes?


  3. Just ran across an Interesting and pertinent article on how elephants — for free — save an estimated $43 billion in CO2 absorption from the atmosphere. Forest elephants tend to eat, stomp, crush, or otherwise disrupt slower growing trees and bushes, which comparatively absorb lesser amounts of CO2; they leave alone hardwood trees, which absorb markedly higher levels of CO2. The ecological effect is this reduces contributions to global warming.

    Sadly, elephants are one of the species whose numbers are being threateningly reduced, through poaching, habitat destruction, and reduced pairs breeding. This is but one more common example of how environmental impacts from humans is contributing to the steady decimation of an important species in the big picture of nature. Sad.


  4. In her concluding pages, Colbert asks, Will human ingenuity be able to overcome the many crises originating with misapplied ingenuity? On the July 25, 2019 PBS Newshour, a segment addressed how science and technology is being used to compensate for the rapid decline of pollinating bees, which are needed for almost three of four crops worldwide. One approach is to use pollinating drones for orchards and other crops. Another is the early stages of development of miniature flying/wing-flapping robots. These are promising potential solutions, but sad commentary on the decimation of bee populations from overuse of pesticides, vulnerability to new parasites from altered land use, and poor nutrition for bees from the agricultural reduction of plants bees have relied on for ages.


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