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When Life Nearly Died: The Greatest Mass Extinction of All Time (2003)

de Michael J. Benton

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3711168,238 (4.04)4
"Today it is common knowledge that the dinosaurs were wiped out by a meteorite impact 65 million years ago that killed half of all species then living. It is far less widely understood that a much greater catastrophe took place at the end of the Permian period 251 million years ago: at least ninety percent of life on earth was destroyed. When Life Nearly Died documents not only what happened during this gigantic mass extinction but also the recent renewal of the idea of catastrophism: the theory that changes in the earth's crust were brought about suddenly in the past by phenomena that cannot be observed today. Was the end-Permian event caused by the impact of a huge meteorite or comet, or by prolonged volcanic eruption in Siberia? The evidence has been accumulating, and Michael J. Benton gives his verdict at the end of the volume. The new edition brings the study of the greatest mass extinction of all time thoroughly up-to-date. In the twelve years since the book was originally published, hundreds of geologists and paleontologists have been investigating all aspects of how life could be driven to the brink of annihilation, and especially how life recovered afterwards, providing the foundations of modern ecosystems."--… (mais)
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Mostrando 1-5 de 11 (seguinte | mostrar todas)
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  SueJBeard | Feb 14, 2023 |
An excellent book, substantially as described below the title (above). Recommended for anyone with an interest in the greatest mass extinction in history. There are many illustrations.

Science magazine has a more recent article on the Permian extinction in their December 9, 2011, issue. It is free to the public by free registration. It is called "Calibrating the End-Permian Mass Extinction." The authors, Shu-zhong Shen and others, reach a date of 252.28 million years ago within about 80,000 years, and an extinction period lasting less than around 200,000 years. They found that the Siberian flood basalts and the land and sea extinctions coincided and were consistent with greenhouse heating and its cascade of environmental consequences which Benton addresses. The precision of this dating is a triumph.

http://science.sciencemag.org/content/334/6061/1367.full
Vol. 334, Issue 6061, pp. 1367-1372
DOI: 10.1126/science.1213454 ( )
  KENNERLYDAN | Jul 11, 2021 |
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. ( )
  ElentarriLT | Mar 24, 2020 |
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 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.”
( )
  Jennifer708 | Mar 21, 2020 |
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 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.”
( )
  Jennifer708 | Mar 21, 2020 |
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When I was a student of palaeontology in the late 1970s, I remember being puzzled by some extraordinary differences of view.
On 5 March 1845, Professor Richard Owen wrote an account of some bones of ancient reptiles that had been brought back by Sir Roderick Impey Murchison from his long peregrinations in Russia in 1840 and 1841.
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"Today it is common knowledge that the dinosaurs were wiped out by a meteorite impact 65 million years ago that killed half of all species then living. It is far less widely understood that a much greater catastrophe took place at the end of the Permian period 251 million years ago: at least ninety percent of life on earth was destroyed. When Life Nearly Died documents not only what happened during this gigantic mass extinction but also the recent renewal of the idea of catastrophism: the theory that changes in the earth's crust were brought about suddenly in the past by phenomena that cannot be observed today. Was the end-Permian event caused by the impact of a huge meteorite or comet, or by prolonged volcanic eruption in Siberia? The evidence has been accumulating, and Michael J. Benton gives his verdict at the end of the volume. The new edition brings the study of the greatest mass extinction of all time thoroughly up-to-date. In the twelve years since the book was originally published, hundreds of geologists and paleontologists have been investigating all aspects of how life could be driven to the brink of annihilation, and especially how life recovered afterwards, providing the foundations of modern ecosystems."--

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