When Life Nearly Died: The Greatest Mass Extinction of All Time

Overall this was a very good read and an enjoyable introduction to paleontology to the casually interested non-specialist. I am a biologist, but you don’t have to be a scientist to enjoy this book about the end-Permian mass extinction event.

The end-Permian mass extinction event occurred about 250 million years ago, and while it’s not nearly as well known as the end-Cretaceous (which did in the dinosaurs), it was far worse, with a loss of 90% of all extant species. For a book about the end-Permian, it contained a great deal about the end-Cretaceous, but I think this can be justified. The end-Cretaceous is so well-known and has so captured the popular imagination that linking a lesser-known but still catastrophic extinction event to show more it will automatically make the lesser-known event more relatable. Because some paleontologists have suggested the end-Permian extinction was caused by an asteroid, the end-Cretaceous also provides a good point of comparison.

Benton explores not only the consequences of the end-Permian extinction as shown in the continental and marine fossil records but also two possible causes. The book was well-written and managed to strike a balance between being accessible to non-specialists and satisfying specialists, who can consult the notes for references to the appropriate scientific papers. However, there is still quite a bit of speculation, especially because Benton’s favored hypothesis involves a series of catastrophic volcanic eruptions that would have triggered the release of massive quantities of methane from (as yet unproven) oceanic reservoirs. The catastrophic series of volcanic eruptions during the appropriate time frame has been established and would have been enough to suppress most photosynthetic activity for years. However, what was never mentioned in the book was how badly this would affect the carbon cycle, and therefore life (all known life is carbon-based). Because this has serious implications for today, I’d like to elaborate.

Photosynthesis removes CO2 from the atmosphere, so any serious decrease in photosynthetic capacity (or an increase in CO2 levels that overwhelms current photosynthetic capacity), would allow carbon dioxide to start accumulating in the atmosphere. The more CO2 in the atmosphere, the more there is to interact with the water in the clouds to make acid rain and to interact with the water in the ocean to feed the reactions that increase ocean acidity (thus knocking out even more photosynthetic capacity). Worse yet, the more acidic the oceans become, the less capable they become of removing carbon dioxide from the atmosphere and incorporating it into the oceanic sediments that ultimately become limestone. The result is that atmospheric CO2 levels go up, and one hell of a vicious cycle is created.

It doesn't even stop there, because photosynthesis also fixes carbon dioxide. So as increasingly acidic water continues knocking out photosynthetic capacity, less and less biologically useful carbon will be available to most other organisms, even as the atmosphere is flooded with carbon dioxide. The problems are so great that I would go so far as to say that the underlying cause of the end-Permian mass extinction event was actually a deranged carbon cycle.

This does relate to the book, because in the last chapter, Benton discusses “current events” (the book was published in 2003), and whether we are at risk of causing a sixth mass extinction event. His primary focus is on how humans are destroying entire habitats as opposed to a few species, and an ecosystem can cope a lot better with the loss of a few species than the loss of entire habitats. While this is true, I think we would do far better to think in terms of a gravely disrupted carbon cycle. Given the human talent for mass deforestation and enthusiasm for releasing large quantities of carbon dioxide into the air, the carbon cycle is already well on its way to becoming deranged again – and a severely disrupted carbon cycle may well take tens of millions of years to recover.

Benton also does a good job showing the rehabilitation of catastrophism in geology. Unfortunately, he also describes young-earth creationists as a “fringe group” without acknowledging that in some ways they are the ultimate catastrophists (e.g., believing the Grand Canyon was formed in a matter of months by the same catastrophic global flood that caused Pangea to break up). Arguing against Lyell’s concept of the uniformity of rates also is something that regularly occurs in that community, because any arguments against it can then be used to call into question all radiometric dating techniques (by saying decay rates have changed over time and are not constant). It was very bothersome to me to keep reading arguments for catastrophism and complaints about young-earth creationists without any effort to address the overlap in beliefs. There were a few other minor irritants, including that an estimate of the total number of species on earth did not include the mention of any members of the plant kingdom.

Despite these issues, I very much enjoyed this book, at least partly because of the writing style. One of my favorite quotes: "Life can best be thought of as a great tree…During a mass extinction, vast swathes of the tree are cut short, as if attacked by crazed, axe-wielding madmen.” show less

I was a geology undergrad during the late 1960's-early 1970's, when two revolutionary ideas were being accepted - the identification of “cryptovolcanic” features as the remnant of extraterrestrial impact, and the acknowledgment of plate tectonics as the driving force behind earth history. I was no longer working in the field but still following it when another revolution took place in the 1980's: the acceptance of impact as a potential agent for mass extinction. Plate tectonics caught on very quickly, but geologists had to be dragged kicking and screaming into first accepting the reality of impact structures and then acknowledging that the process of blowing a crater tens of kilometers wide and deep into the Earth would probably show more have an adverse effect on the biosphere. The reason for georeluctance was the forbidden word “catastrophism”.

In this book about the Permo/Triassic extinction event, author Michael Benton does an excellent job explaining why catastrophism was anathema for so long, with about a third of the book devoted to an excellent overview of the history of stratigraphy. Benton discusses the replacement of catastrophist theories based on Biblical accounts with the idea of “uniformitarianism”: that “the present is the key to the past” and that all geological features can be explained by processes observable right now - erosion, tectonic uplift, isostasy. Uniformitarianism became so ingrained that it reached the level of dogma. Strangely for people dealing with immense time units, until recently geologists never grasped that on a geological scale, events that are rare or unknown from the human perspective are just as “uniformitarian” as more mundane processes. If a clod be washed away by the sea, geologists saw it as the work of the uniformitarian process of erosion; but if Lucifer’s hammer came in from the Oort cloud and devastated the planet nobody seemed to get that it was just another natural process on a different scale (in fact, if anything is more ordinary since it’s more predictable; if we happened to see the incoming body far enough in advance we could calculate impact time to the minute and impact location to the kilometer, while the washing away of any particular clod is beyond reasonable calculation). Similarly, it’s now recognized that a lot of sedimentary structures are better explained by “rare” (in human terms) events - 1000-year floods, 10000-year hurricanes, and 100000-year supervolcanoes - than by daily erosion and sedimentation.

Paleontology was the discipline with the most difficulty dealing with these new ideas; many paleontologists resisted the idea of mass extinction at all (it wasn’t acknowledged until the 1990's that there was a loss of terrestrial fauna equivalent to the devastation of marine groups at the Permo/Triassic boundary - about 90% of all species). When Alvarez et al. proposed impact as the agent behind the Cretaceous/Tertiary extinction event, many paleontologists - including some very famous ones - went ballistic at the idea of physicists and astronomers intruding where they weren’t wanted. There are still one or two papers at every GSA conference proclaiming that there’s no evidence for an end Cretaceous extinction in liverworts or acanthocephalans or whatever group the presenter happens to study. Most, however, accept if grudgingly the smoking gun of iridium spikes and shocked quartz world-wide.


The Permo/Triassic event, as Dr. Benton points out, is a different kettle of coelacanths. It’s a lot older than the end Cretaceous, so a lot more of the evidence has been eroded, buried or subducted. Further, the Permian was a time of high continentality - everything was packed together in Pangaea - as opposed to the Cretaceous, where the reverse held true and there were a lot of epicontinental seas to accumulate easy-to-collect fossils in their sediments. Permian strata, especially late Permian, are quite rare and the best places to study the boundary zone are in politically and logistically difficult places - China, Russia and Greenland. Finally, there’s no smoking gun - no boundary clay rich in iridium, shocked quartz and impact glass. In fact, detailed study of the Permo/Triassic boundary suggests that the event, whatever it was, was not quite as abrupt as the KT impact; depending on sedimentation rates, the PT event seems to have taken somewhere between 10K and 10M years.

So what happened? Dr. Benton holds for a Paleozoic equivalent of Murder on the Orient Express - everybody did it. Flood basalt eruptions in Siberia caused huge emissions of sulfur dioxide, which triggered a period of glaciation due to increased albedo. Continuing eruptions emitted fluorine and chlorine that combined with the sulfur dioxide to cause severe acid rain, resulting in widespread loss of terrestrial vegetation, which then caused terrestrial fauna to collapse from starvation and near shore marine fauna from greatly increased sedimentation (no longer any roots to hold the soil). Finally, when all the acids settled out, volcanic carbon dioxide triggered global warming, which melted glaciers and permafrost and led to gas clathrate “burps” that further warmed things with methane,

Is this plausible? Well, it’s not completely implausible, but even Dr. Benton admits problems. For one thing, although the Siberian flood basalt eruptions were large, there have been others as large or larger - including the Snake River basalts - that didn’t seem to cause any mass extinctions. Dr. Benton goes out on a limb with the gas clathrate hypothesis - in what’s otherwise a well-reasoned book, as a supporting example he cites, of all things, the Mary Celeste, suggesting that a methane burst caused the crew to leap overboard to avoid asphyxiation. Dr. Benton buys the mythical “breakfast on the table” story for the Mary Celeste, and doesn’t explain why jumping off a ship would seem to be a solution for a suffocating crew. (See my review of Ghost Ship) for more information on Mary Celeste mythology). Nevertheless, in the absence of anything better the Siberian flood basalts will do. There’s a lot of carefully presented evidence in terms of isotope ratios and sediment patterns that backs up the theory.

There aren’t many negatives to this book; the only problem I see is that Dr. Benton is a vertebrate paleontologist and it shows. He feels he has to go to considerable length to explain what brachiopods and tabulate corals and other common invertebrates are but has no problem with expecting his readers to keep track of gorgonopsians and pareiasaurs and dicynodonts and the rest of the grotesque but strangely endearing Permian vertebrates. A minor quibble - the book as a whole is quite valuable - even if the Siberian basalt theory is replaced by something else the discussion of the history of catastrophism and the identification of the Permian would be worthwhile. show less

Interesting and erudite, in discussing the greatest mass extinction of all time this book reminds the reader how long interesting life was around before there were dinosaurs. With considerable grace the author weaves together the human history of this research (going back to the beginnings of geology), what it is like to be a researcher now, and the discoveries that are being made.

The big five mass extinctions are all touched on, with special attention paid to the end of the dinosaurs. The book lays out the cases that the impact at Chicxulub ended the dinosaurs, and the Siberian Traps (a massive, sustained volcanic eruption) caused the Permian extinction. Skeptics will raise the point that similar disasters happened at other times show more without corresponding mass extinctions. Benton does not hide from this, but all he can do is note that this is a mystery at present.

Recommended. show less

Overall this was a very good read and an enjoyable introduction to paleontology to the casually interested non-specialist. I am a biologist, but you don’t have to be a scientist to enjoy this book about the end-Permian mass extinction event.

The end-Permian mass extinction event occurred about 250 million years ago, and while it’s not nearly as well known as the end-Cretaceous (which did in the dinosaurs), it was far worse, with a loss of 90% of all extant species. For a book about the end-Permian, it contained a great deal about the end-Cretaceous, but I think this can be justified. The end-Cretaceous is so well-known and has so captured the popular imagination that linking a lesser-known but still catastrophic extinction event to show more it will automatically make the lesser-known event more relatable. Because some paleontologists have suggested the end-Permian extinction was caused by an asteroid, the end-Cretaceous also provides a good point of comparison.

Benton explores not only the consequences of the end-Permian extinction as shown in the continental and marine fossil records but also two possible causes. The book was well-written and managed to strike a balance between being accessible to non-specialists and satisfying specialists, who can consult the notes for references to the appropriate scientific papers. However, there is still quite a bit of speculation, especially because Benton’s favored hypothesis involves a series of catastrophic volcanic eruptions that would have triggered the release of massive quantities of methane from (as yet unproven) oceanic reservoirs. The catastrophic series of volcanic eruptions during the appropriate time frame has been established and would have been enough to suppress most photosynthetic activity for years. However, what was never mentioned in the book was how badly this would affect the carbon cycle, and therefore life (all known life is carbon-based). Because this has serious implications for today, I’d like to elaborate.

Photosynthesis removes CO2 from the atmosphere, so any serious decrease in photosynthetic capacity (or an increase in CO2 levels that overwhelms current photosynthetic capacity), would allow carbon dioxide to start accumulating in the atmosphere. The more CO2 in the atmosphere, the more there is to interact with the water in the clouds to make acid rain and to interact with the water in the ocean to feed the reactions that increase ocean acidity (thus knocking out even more photosynthetic capacity). Worse yet, the more acidic the oceans become, the less capable they become of removing carbon dioxide from the atmosphere and incorporating it into the oceanic sediments that ultimately become limestone. The result is that atmospheric CO2 levels go up, and one hell of a vicious cycle is created.

It doesn't even stop there, because photosynthesis also fixes carbon dioxide. So as increasingly acidic water continues knocking out photosynthetic capacity, less and less biologically useful carbon will be available to most other organisms, even as the atmosphere is flooded with carbon dioxide. The problems are so great that I would go so far as to say that the underlying cause of the end-Permian mass extinction event was actually a deranged carbon cycle.

This does relate to the book, because in the last chapter, Benton discusses “current events” (the book was published in 2003), and whether we are at risk of causing a sixth mass extinction event. His primary focus is on how humans are destroying entire habitats as opposed to a few species, and an ecosystem can cope a lot better with the loss of a few species than the loss of entire habitats. While this is true, I think we would do far better to think in terms of a gravely disrupted carbon cycle. Given the human talent for mass deforestation and enthusiasm for releasing large quantities of carbon dioxide into the air, the carbon cycle is already well on its way to becoming deranged again – and a severely disrupted carbon cycle may well take tens of millions of years to recover.

Benton also does a good job showing the rehabilitation of catastrophism in geology. Unfortunately, he also describes young-earth creationists as a “fringe group” without acknowledging that in some ways they are the ultimate catastrophists (e.g., believing the Grand Canyon was formed in a matter of months by the same catastrophic global flood that caused Pangea to break up). Arguing against Lyell’s concept of the uniformity of rates also is something that regularly occurs in that community, because any arguments against it can then be used to call into question all radiometric dating techniques (by saying decay rates have changed over time and are not constant). It was very bothersome to me to keep reading arguments for catastrophism and complaints about young-earth creationists without any effort to address the overlap in beliefs. There were a few other minor irritants, including that an estimate of the total number of species on earth did not include the mention of any members of the plant kingdom.

Despite these issues, I very much enjoyed this book, at least partly because of the writing style. One of my favorite quotes: "Life can best be thought of as a great tree…During a mass extinction, vast swathes of the tree are cut short, as if attacked by crazed, axe-wielding madmen.” show less

This is a nicely written book that investigates the Permian mass extinction event approximately 250 million years ago that wiped out 90% of all species on Planet Earth. The author starts with the history of geology and paleontology, and describes the various historical means of approaching geological problems. The author also takes a look at the Cretaceous mass extinction which killed the dinosaurs. This is an up-to-date (2015) edition of the book that includes new information on what caused the Permian mass extinction and how life recovered afterwards. There is a fair amount of technical terminology at the beginning of the book, but this doesn't detract from the beautiful writing and fascinating information.

This is a fine explanation of the greatest mass extinction to which the geologic record attests, the extinction not at the end of the Cretacious Period, but the much bigger one at the end of the Permian. The author draws us into the controversy surrounding mass extinction events, showing the deep bias Chalres Lyell put on the science, and how long it took science to slough off his legacy. He closes in on the subject quite well, and in the course of learning about this great decadal extinction (where species died off ten to one), the closest life on the planet has come to being extinguished.

I was fascinated by his educated surmise (and that's what it is, I guess; a conjecture backed up by quite a few facts, and a paucity of other show more reasonable explanations) on what caused the event. It was not extraneous to the planet. It was geological in origin. Thousands of years of a major basalt volcanic activity in the Siberian region of Gondwanaland raised the temperature of the planet, extinguishing many niches of life, until the tipping point was reached in the polar regions, with the release of a series of huge methane burps. This was the final twist of the knife, and most life died, the oceans poisoned as well as the air, with oxygen robbed and most animals unable to breathe.

All this is of more than scholarly interest. At present, humanity is shoving into extinction many species in specialized niches, at an alarming rate . . . and causing some degree of global warming (though so far nowhere near as bad as what happened at the End Permian Extinction). In this sense, humanity is acting as the vulcanism in Siberia. We do not want to stress the equilibrium to unleash the methane burp, that's for sure. That would almost certainly spell our end as well as the end of most life.

The author ably puts all this into historical context, the fascinating history of geology and paleontology. I kept coming back to a figure he did not mention (because he had no need): Herbert Spencer.

Spencer was a major evolutionist. But his basic perspective was not just of evolution. He saw the great sweep of history as cyclical, with evolution leading to equilibrium, only to degrade in "dissolution" (what sociologist Jonathan Turner calls "destructuring"). Spencer spent more time and effort explaining the structuring elements of differentiation (diversitifcation) and integration (interdependence) than on the destructuring process. Surely what he said about destructuring is mostly incorrect. For the major events of system-wide (the super-organice ecology of the planet) seem to be intrusions from above (space, with asteroid or comet hits; increased radiation) or from below (increased vulcanism, or magnetic pole inversions . . . something not talked about much in any of this, but something that could certainly destabilize the Van Allen belts to increase radiation during the switching perdio).

It looks like, these days, the cyclical elements of Spencer's conception are now getting the complete attention they deserve. It's not just the "progress" of increased biological diversity and organism complexity that sparks scientific interest, but also the periods where diversity decreases and life becomes less viable.

This book is a great step in helping non-scientists grasp that part (the darkest part) of terrestrial natural history, too. show less

It's difficult to give this book just one rating. The first half easily deserves five stars. The history of the discovery of the end Permian extinction reads like a detective story with a lot of twists and turns that are well explained. But then, in the second half of the book, the reader is suddenly left to their own devices with a lot of unexplained material gone through too quickly. Only towards the very end does the author pick up the way of story-telling of the beginning. It's as if the book had to be finished, and that makes the second half rather frustrating to read. So only three stars for the second half.

The four stars I gave it is the mathematical average, but the book is partly better and worse than that rating.