Extinction in the Anthropocene

June 16, 2024

A review by John Kricher

The End of Eden: Wild Nature in the Age of Climate Breakdown, by Adam Welz

Bloomsbury Publishing, 2023

288 pages, hardcover

The metaphorical title of this somber book obviously refers to the biblical story of Eden, which provided an early lesson about ill-advised human boldness and overstepping. The South African author, Adam Welz, argues convincingly that human actions coupled with an alarming lack of attention to global environmental consequences are resulting in a rapidly increasing climate breakdown, caused, as was the case with the mythical Eden, by human boldness and overstepping. As the present century unfolds, nature will continue to change dramatically throughout the planet, a change for the worse for thousands if not millions of species including most bird species. Millions of humans will also be the worse for it. The fundamental cause is that humans cannot effectively come together for the sake of the planet. Let that sink in. This is not a fun book to read, but it should be read by anyone who is empathetic to nature and what is happening to nature as climate change worsens. Many bird-focused examples are presented throughout the book. In nine chapters, Welz makes a carefully reasoned, urgent, and scary case for what he terms global climate breakdown.Global diversity patterns have changed dramatically throughout Earth’s long history. Among such changes include five major extinction events, such as the famous Cretaceous asteroid that eliminated all large dinosaurs about 66 million years ago. Profound climate change, directly or indirectly, was the cause of all five extinction events. The sixth major extinction is now ongoing, and we humans are the cause. The easiest way to disrupt global ecosystems and bring about large-scale extinctions is to rapidly change the global climate (which is exactly what the Cretaceous asteroid strike did). Rapid global climate change pulls the adaptational ecological rug out from under whole ecosystems, indeed whole biomes. In the case of human actions, climate impact is augmented by continued habitat loss from economic actions such as, for example, replacing huge areas of tropical forest with oil palm plantations and littering the oceans with millions of tons of plastic waste.

Above all else, organisms must be adapted to the climate in which they reside. Some, not adapted to all seasons in a particular location, either migrate, hibernate, estivate, survive as seeds, or do whatever temporary escape their evolution has provided. Many bird species are global migrants, and you might think all they have to do is to fly away to a better habitat should their habitat decline or be eliminated. Well, maybe. But for many species it doesn’t work that way. You cannot escape if there is nowhere to go. Welz provides a convincing and carefully researched array of examples showing that global climate breakdown is accelerating at a pace where huge numbers of species are threatened. And it is complicated, not simple.

Most birders now know that bird numbers in North America have declined by almost 30 percent over the past 50 years for a total loss of three billion birds. But the public, including many birders, are slow to notice that such declines mean they are witnessing ongoing extinctions in progress that are expected to accelerate. Still, for much of humanity, extinction, if a worry at all, seems like “tomorrow’s worry,” not today’s. We still see Evening Grosbeaks on occasion, though their total population may now be reduced to barely 10 percent of what it had been. Many elderly birders might say that not a single bird species has gone extinct during their lifetimes. But human lifetimes are short in terms of global dynamics. Consider two examples that Welz explains, both of which show how rapid climate change is moving species toward extinction.

Southern Yellow-billed Hornbills are common in the Kalahari Desert of South Africa. They may not be for much longer. A recent study involving forty hornbill nest boxes suggests they are declining rapidly. Like most hornbill species, the female of the pair walls herself into a tree cavity (or nest box) by applying mud that hardens, “trapping her” until she breaks out when the young bird is ready to fledge (there are typically two eggs laid, but usually only one young fledges). This leaves the male of the pair to do 100 percent of the foraging to feed both female and young. This breeding system has worked for hundreds of generations. Not anymore. Rising air temperatures in the region now exceed the heat tolerance of male birds. Male hornbills remain thermally neutral at air temperatures as high as 34.5ºC (94.1ºF). But as climate change drives air temperatures above their thermal tolerance zone, males are forced to spend considerably less time foraging and instead idle in shade during the heat of the day in order to reduce heat stress. The result is that they cannot adequately forage and provide for the female and young. Between 2008 and 2020, the breeding rate has dropped from 1.1 young produced per nest to 0.4, so far fewer young are produced annually. But hornbills live a long time. Birders on a tour of the region will likely see the species commonly for some years to come, even as heat stress continues to reduce reproductive success. Once the older birds perish it will then become clear that the species is declining to extinction, at least for that area.

Are Red Knots extinct? No, not yet. But as Welz explains, Eurasian populations are seriously stressed by increasingly early Arctic insect emergence, caused, of course, by accelerating global warming in their Arctic tundra breeding grounds. Birds now arrive well after insect emergence, meaning that there is much less available insect food to feed a new generation of knots. Thus, the birds fledge smaller in body size than was usual, including their beak dimensions. The young migrants dutifully fly to their African coastal wintering grounds, but smaller beak length reduces their ability to feed as they cannot probe as deeply in the mud for clams. Thus, the birds fare worse than was historically the case in their nonbreeding range. Their population in the region has dropped by 80 percent over four decades. Red Knots face a double whammy, one on their breeding grounds and one on their wintering grounds, that puts them on an extinction path unless they can somehow adapt by changing migration timing or food gathering behavior.

The “field marks” of ongoing extinction are such characteristics as steadily declining populations, changing dispersal patterns, and increased vagrancy. Climate breakdown does not hit as abruptly as an asteroid, but it is hitting, and what Welz is suggesting is that climate breakdown is gaining in speed and impact by the day.

The Rattling Cisticola is one of many bird species of the genus Cisticola, and it happens to be uncommonly common in parts of Namibia. In a chapter titled “Fertile Air,” Welz masterfully explains the complex ecology of savanna ecosystems and how they have been changing with increasing atmospheric carbon dioxide and global warming. In this case, a once diverse and fertile savanna of mixed shrubs, grasses, and scattered trees has rapidly been reduced to a monotonous low diversity ecosystem of grassveld, made up of thorn-covered dry shrubs that are now almost the exclusive real estate of many, many Rattling Cisticolas. There are no longer cheetahs, grazing mammals, or the diverse bird community that once typified the region. The reason is that climate warming is driving changes in a complex process called ecological succession. Be warned, reader, you must be patient with this book. Some of the topics that Welz explains so skillfully are nonetheless somewhat complex, and this is one of them. Welz describes in detail how global warming is altering the pattern of plant photosynthesis, converting what was once a stable savanna into an ecologically far less diverse system. Of Rattling Cisticolas.

The final chapter, symbolized by the head of Medusa (the threatening mythological beast with multiple nasty serpents growing from its head), brings climate breakdown into sharp and pragmatic focus. Welz raises the issue of “nature’s rights,” an issue brilliantly championed long ago by Aldo Leopold in A Sand County Almanac. Why is climate change so difficult for the world’s multiple nations to confront and fix? Would it be as difficult if humanity could conceptualize nature—the trees, the bugs, the birds—as having existential “rights” as we afford to ourselves in society? Alas, such a view remains far too long a reach for most of today’s citizenry, cultures, and, more to the point, its various governments. Instead, we are committed to a strong philosophical dualism between us and nature. We use nature for “resources,” food and fiber and whatever else we deem important. Indeed, we continue, for what we argue are pragmatic reasons, to plunder nature.

Holistic attitudes about nature have been constantly overwhelmed by humanity’s historical cultural focus on political boundaries, extraction of resources, and, of course, the dependency on continual capitalistic-modeled economic growth. I discussed this issue in a previous book, The Balance of Nature, Ecology’s Enduring Myth (2009). Rather than use Medusa as a symbol, I invoked Marley’s Ghost from Dickens’ A Christmas Carol. I am confident that Welz would agree that metaphorically “Marley’s ghost is staring us in the face.” We have very little time left to alter course regarding carbon management, energy usage, and conservation of ecosystems. Being pessimistic is, at least at this point, more and more akin to being realistic. Welz tries, as did I, to end on an encouraging note, but he was obviously struggling. I was too.

Reading Welz’s tightly and well-written book should disabuse anyone of feeling indifferent to what is happening now in nature. But how many will read it? How many weeks will it be on various bestseller lists as it deserves to be? Will it be on any bestseller lists? Some birders choose to be myopic or downright oblivious about the threats that climate change presents to nature as they eagerly focus their bins only on their targets, the birds de jour, while giving little or no attention to the very features of the ecosystem that contain and sustain birds . . . and the planet. At an ABA convention back in 2000, my wife and I were joined for breakfast by a well-traveled birding couple, and of course we began talking about birds. The gentleman, proud of his global life list, had an agenda that he forcefully expressed when he saw from my badge that I was a member of the ABA board. He asked why the ABA was now embracing bird conservation and what was I planning to do about it as a board member. He was appalled. In his view, conservation was the Audubon Society’s job. The ABA stood for birding, period. Not “watching” birds, not ornithology, and certainly not politically-charged conservation issues. Just birding and listing. Go out, find bird, tick, period. The man told me that he couldn’t care less if a bird species went extinct after he saw it. This conversation, now over two decades old, is still vivid in my memory and remains disturbing. Why? Because there are likely more folks with his viewpoint, and it is scary to wonder how many. So, to borrow the Inca Dove’s lament, is there “no hope?”


John Kricher taught ecology and ornithology at Wheaton College, Massachusetts, for 48 years. He is a Fellow in the American Ornithological Society, as well as Past President of the Wilson Ornithological Society and the Association of Field Ornithologists. In 2023, he received the Alexander F. Skutch Medal from the Association of Field Ornithologists for his contributions to tropical ecology. John is author of the acclaimed New Neotropical CompanionPeterson Reference Guide to Bird Behavior, and other works.