February 24, 2024

I, Science

The science magazine of Imperial College

By Anjana Nair
10th February 2022

The Sixth Extinction: An Unnatural History is a nonfictional account of what Kolbert calls “the sixth extinction”: an extinction event caused by humans like ones that destroyed earlier forms of life, like the dinosaurs and megafauna. The book revisits five previous mass extinction events spanning five hundred million years and compares them to the rapid, widespread extinctions of a range of species like frogs, corals, birds, and rhinos happening today. These extinctions are a result of human-created global warming and ocean acidification, the destruction of forests, and the spread of invasive species around the world. What’s more, these actions will determine the course of life on the planet long after our species is gone.

The story of The Sixth Extinction comes in thirteen chapters. Each tracks a species that is in some way emblematic, like the American mastodon, the great auk, an ammonite that disappeared at the end of the Cretaceous alongside the dinosaurs. The creatures in the early chapters are long gone, and this part of the book is mostly concerned with the great extinctions of the past and the twisting history of their discovery, starting with the work of the French naturalist Georges Cuvier. The second part of the book takes place very much in the present – the increasingly fragmented Amazon rainforest, the fast-warming slope in the Andes, and the outer reaches of the Great Barrier Reef.

Kolbert chooses this kind of space for the usual journalistic reasons like established research centers, ongoing expedition, and acquired guidance. Finally, we approach the modern-day and the devastating effects of the Industrial Revolution. Since the 1800s, water and carbon dioxide levels have been rising, which has led to the extinction of many animals prone to pollution. Furthermore, international trade has quickly spread diseases and invasive species to new parts of the world, much like when Europeans brought diseases like smallpox to the Americas for the first time. Like Kolbert writes,

“If extinction is a morbid topic, mass extinction is, well, massively so.”

The book thus asks us to look back over vast periods of time only to realise how humankind has impacted our planet and its very ability to sustain us.

The Summary:

The book begins near the beginning of evolution – when amphibians started to begin forming. Frogs, which are the most common type of amphibian, had ancestors dating back 400 million years. These have persisted for longer than the dinosaurs, yet today, their numbers are dwindling. A particular example noted in the book is that of a species of frog native to Panama. Today, frogs going extinct in the 21st century. To this, one might think that frogs are disappearing in areas where many human beings live; however, frogs that live in pristine areas, where no humans live, are also going extinct. Kolbert learns that these frogs are now dying because of a fungus not native to the region, which could only have been brought there by the extensive networks of humanity’s interregional trade. The book then continues to discuss some previous extinctions, such as the mastodon.

Part 2 of the book increasingly focuses on the fragmented Amazon rainforest, the fast-warming slope in the Andes, and the outer reaches of the Great Barrier Reef. Kolbert travels to the Great Barrier Reef, where scientists show her the impact that increased temperature and acidity have had on the diversity of life in coral reefs. Lastly, the final chapters paint a bleaker portrait of human nature, suggesting that humans might have a propensity to destroy even beings that resembles themselves close enough to interbreed. One important factor in The Sixth Extinction is how well human travel is described. Since prehistoric times, different species have been confined to different ecosystems, each ecosystem has developed a complex equilibrium, predicated on its isolation from the rest of the world. Due to modern human travel and transportation, however, different species have travelled around the world, upsetting the equilibrium of the new ecosystems.

The verdict:

The Sixth Extinction studies the relationship between human beings and the environment and concludes that human behaviour is on the verge of causing (or may have already caused) mass extinction in the history of the planet. All over the world, different species are already going extinct, thanks to the declining amount of available undeveloped land, and the rising temperature. In her book, she thus paints a bleak picture of the human race. Like Kolbert argues –

“The survival of the human species, while important, isn’t the most important question we should be asking.”

Perhaps, instead, we should focus on the present state of life on Earth: right now. No matter what decisions humans make, it is already clear that “the Sixth Extinction will continue to determine the course of life” for a long time to come. This book is a must-read if one demands change and is likely motivated to do so.  Kolbert provides a fascinating document of what an extinction event looks like when it unfolds in slow motion, and how our actions, and inaction, are affecting it daily. But the book is written in a way that sometimes reminds an answer on a history test — one packed full of details, but some so redundant and irrelevant to the narrative or to the point, that they often convey the feeling the author wants to make sure we understand she has done all the research and acquired all the facts. Nevertheless, this is a fascinating read that ends too soon.