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Under a Green Sky: Global Warming, the Mass Extinctions of the Past, and What They Can Tell Us About Our Future
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Product Description
By looking backward at the course of great extinctions, a paleontologist sees what the future holds.
More than 200 million years ago, a cataclysmic event known as the Permian extinction destroyed more than 90 percent of all species and nearly 97 percent of all living things. Its origins have long been a puzzle for paleontologists. During the 1990s and the early part of this century, a great battle was fought between those who thought that death had come from above and those who thought something more complicated was at work.
Paleontologist Peter. D. Ward, fresh from helping prove that an asteroid had killed the dinosaurs, turned to the Permian problem, and he has come to a stunning conclusion. In his investigations of the fates of several groups of mollusks during that extinction and others, he discovered that the near-total devastation at the end of the Permian period was caused by rising levels of carbon dioxide leading to climate change. But it's not the heat (nor the humidity) that's directly responsible for the extinctions, and the story of the discovery of what is responsible makes for a fascinating, globe-spanning adventure.
In Under a Green Sky, Ward explains how the Permian extinction as well as four others happened, and describes the freakish oceans—belching poisonous gas—and sky—slightly green and always hazy—that would have attended them. Those ancient upheavals demonstrate that the threat of climate change cannot be ignored, lest the world's life today—ourselves included—face the same dire fate that has overwhelmed our planet several times before.
Product Details
- Amazon Sales Rank: #795084 in Books
- Published on: 2007-04-01
- Released on: 2007-04-17
- Format: Bargain Price
- Number of items: 1
- Binding: Hardcover
- 256 pages
Editorial Reviews
From Booklist
Popular science writer and paleontologist Ward presents breaking news about the link between past mass extinctions and global warming. Disarmingly engaging, Ward combines tales of his own punishing fieldwork with a piquant history of the controversies that have dogged scientists seeking the cause of the "mother of all extinctions" in the Permian period. This provides the foundation for a stunning discovery: evidence of past greenhouse extinctions. As Ward carefully parses the data and its implications, he observes, "the key to climate change seems to be both the level and the rate at which carbon dioxide rises in the atmosphere," no matter its source. Ward also illuminates the symbiosis between ocean currents and climate change, then explains why, as the northern ice cap melts, it is likely that the Atlantic conveyor current system will be altered, thus accelerating climate change. Ward asserts that humankind has flourished during a remarkable period of climatic stability and notes how tragic it will be if our carbon habit brings this boon to a catastrophic end. An important addition to the necessary literature of global warming. Donna Seaman
Copyright © American Library Association. All rights reserved
Review
"A sobering and valuable perspective . . ." (Science )
For RARE EARTH:"A stellar example of clear writing . . ." (American Scientist )
About the Author
Dr. Peter D. Ward is a professor of biology and earth and space sciences at the University of Washington in Seattle. He also serves as an astrobiologist with NASA. Ward is the author of more than a dozen books, including the highly acclaimed Rare Earth: Why Complex Life Is Uncommon in the Universe with Donald Brownlee and Out of Thin Air: Dinosaurs, Birds, and Earth's Ancient Atmosphere.
Customer Reviews
This Will Be A Short Review: Read The Book!
Mr. Flygore and others have dispassionately summarized Under A Green Sky. Pardon me if I don't repeat their efforts. The significant theses which Peter Ward presents are: 1. geologically rapid climate change has been the underlying cause of most great "extinction" events. Those events have been, as S Gould hypothesized, major drivers of evolution.2. drastic climate change has not always been gradual; there is good empirical evidence of catastrophic warming events taking place in centuries, perhaps even decades. 3. the impact of atmospheric warming is most potent in its modification of ocean chemistry and of circulating currents; warming inevitably leads to non-mixing anoxic dead seas. 4. we are already in the middle, not the beginning, of an anthropogenic global warming, caused by agriculture and deforestation, which began some 10,000 years ago but which is now accelerating exponentially; though the earliest wave of anthropogenic warming has been stabilizing and beneficial to human development (civilization), it appears to have the potential for catastrophic effects within a lifetime or two.
Mr. Ward's other recent book, Out Of Thin Air, makes the case for changes in atmospheric chemistry being a major driver of evolution at the level of family and even order. This book recapitulates some of that hypothesis and the evidence to support it. I can hardly imagine that you will want to read one without wanting to read the other. This book is the friendlier to the non-scientist, made readable by an anecdotal science-adventure framework. In short, it's a pleasure to read... until you catch the spoor of Ward's dire predictions for our common future.
As a paleobotanist, Ward is well positioned to "see the whole picture" of climate change in the past, but he also points the reader toward other significant studies of the same events. One such is Tony Hallam's "Catastrophes and Lesser Calamities". Hallam is an oceanographic paleontologist; his research focuses on rising and falling sea levels, and on the causes and effects thereof, which he correlates very convincingly with extinction events, and which he presumes to be chiefly the result of tectonic plate movement. Ward's analysis based on atmospheric changes and Hallam's based on oceanic changes are, I dare say, more or less complementary. Both have radical implications for the current Darwinian model of evolution. Both have horrendously alarming implications for the fairly near future of humankind.
I note that Under A Green Sky is ranked 22,897th in sales on amazon, with 12 reviews. For comparison, Unstoppable Global Warming: Every 1500 Years - a book of politicized pseudo-science - is 665th in sales, with 131 reviews, the majority gloatingly favorable. We're in trouble.
Green Sky In the Morning, Humanity Take Warning
Mass extinctions periodically reshape life on Earth. The best known, the Cretaceous - Tertiary (K-T) boundary, ended the reign of the non-avian dinosaurs approximately 65 MYA when an asteroid roughly 10 kilometers wide gouged the Chicxulub crater near the Yucatan Peninsula, setting the stage for mammals, including Homo sapiens, to become the dominant terrestrial vertebrates.
Another extinction event, the Permian - Triassic (P-Tr), some 251 MYA, is informally known as 'the Great Dying.' Up to 96 percent of all marine species and 70 percent of terrestrial species were erased as global ecosystems crumbled. Life itself nearly died - and Peter Ward makes a compelling case in "Under a Green Sky: Global Warming, the Mass Extinctions of the Past, and What They Can Tell Us About Our Future" that global warming was the primary culprit.
The occurrence of mass extinction events is not open to debate - the data is in the strata - available to any researcher diligent enough to decode the physical evidence. Unlike some global warming books "Under a Green Sky" carefully examines the fossil and climate record to justify models and simulations designed to predict future events. Ward, a paleontology professor at the University of Washington, and a NASA staff astrobiologist, invokes runaway global warming as the primary driver of the P-Tr extinction - and convincingly demonstrates that an anthropogenic (human-caused) encore is the obscene outcome of business as usual energy policies.
"Under a Green Sky" recounts how scientists examine mass extinctions and determine plausible causes based on paleontological and geological evidence. After the K-T event was convincingly attributed to an asteroid strike, extraterrestrial (ET) impacts because the default explanation for other mass extinctions. Ward avoided the ET impact bandwagon and pursued a more nuanced approach by examining the fossil record in painstaking detail to determine if extinctions happened slowly, in phases, or all at once - only the last option favors an impact hypothesis.
If the pace of extinction rules out an impact event, what other agent could kill so indiscriminately across land and sea on a global scale? Scientists can measure past atmospheric concentrations of greenhouse gases such as carbon dioxide or methane by analyzing isotope ratios in rocks and counting stomata, the microscopic pores found on the under side of leaves. Both methods show that a major greenhouse episode took place at the end of the Permian and continued into the early Triassic. On land Therapsids (mammal-like reptiles) made way for the dinosaurs - a topic covered in Ward and Ehlert's superb Out of Thin Air: Dinosaurs, Birds, And Earth's Ancient Atmosphere.
Life's nemesis was ultimately found on the P-Tr ocean floor. ET impact events like the K-T extinction kill ocean life from the surface down - and most losses take place in the upper half of the ocean. Surprisingly, to impact partisans, the P-Tr killer struck first in the ocean depths and moved upward. Dark bands in P-Tr strata signal the presence of anoxic (without-oxygen) archaea and bacteria - potent producers of greenhouse accelerating methane or deadly hydrogen sulfide gas. How did these usually innocuous and ancient organisms devastate life on Earth?
The Pangean supercontinent formed halfway through the Permian. Availability of shallow aquatic environments diminished, ocean currents and weather patterns were radically altered, and seasonal monsoons lashed coasts separated by a vast interior desert. These changes stressed the global ecosystem - much as humanity does today - then global warming triggered by the Siberian Traps, the largest known volcanic eruption in Earth history, initiated the coup de grace by delivering massive amounts of carbon dioxide and sulfur dioxide into the atmosphere over a 700,000 year period as the Permian drew to a close.
Temperatures soared 10 - 30 degrees Celsius (18 - 54 degrees Fahrenheit) as sulfur dioxide combined with water vapor to form acid rain. The ocean conveyor which carries warm and poorly oxygenated surface water toward the poles where it cools and is re-oxygenated before sinking and making its way back to the equator shut down.
The collapse of the ocean conveyer was catastrophic. Aerobic (with-oxygen) life in the deep sea suffocated as oxygen disappeared. Anoxic replacements quickly filled the vacant niche until the killing zone reached the surface of the global Panthalassic Ocean. Methanogenic archaea and bacteria produced prodigious amounts of methane - a far more efficient greenhouse gas than carbon dioxide - while sulfate-reducing microorganisms released unprecedented amounts of deadly hydrogen sulfide (rotten egg gas) into the ocean and atmosphere. The sky literally turned green as oxygen levels dwindled, the ozone layer disappeared, and hydrogen sulfide poisoned animals and plants. Pangaea, already arid, approached desiccation - more than enough to drive the mother of all mass extinctions.
Fast forward 251 million years to the present. Ward presents three possible Anthropocene scenarios:
1. Humanity manages to keep atmospheric carbon dioxide levels below 450 ppm (parts per million) by the year 2100. Earth warms somewhat, additional ice melts, but sea level rise is manageable and life goes on much as it has in the past - but any pending ice age will be indefinitely postponed. This outcome, as Ward notes, is hopelessly optimistic unless a massive initiative to limit or sequester greenhouse gas emissions is successfully implemented within this decade.
2. Greenhouse gas emissions accelerate as China and India continue to industrialize; carbon dioxide levels reach 700 ppm by the year 2100. Rising seas have forced countries to relocate some essential coastal infrastructure and deal with regional population displacements. Scientists note that the ocean conveyor recently shut down - triggering climate and weather pattern changes that even politicians can't ignore. Famine and scarcity replace consumer culture as societal norms. The future is bleak but technological civilization may continue to exist if it adapts quickly enough.
3. Carbon dioxide levels hit 1,100 ppm by 2100. The result resembles the worst parts of the bible - no adequate secular alternative is available. Earth is 10 degrees Celsius warmer. All of the world's ice is melting. Sea level rise is measured in meters. Much of the world's population is displaced by rising waters and vital infrastructure losses cannot be replaced. Polar bears are long gone, Homo sapiens is the latest endangered species. The ocean conveyor shut down decades ago. Signs of deep ocean anoxia are increasingly apparent and appalling - the sky turns a sickly shade of green. The sixth great mass extinction is underway. Remaining governments fight savage wars over scarce resources as entire ecosystems collapse. Natural selection and humankind are brutally reacquainted when medicine reverts to pre-industrial norms. Rampant famine and disease causes a global population implosion. Humanity will probably survive but a second stone age is the most likely outcome.
Those who forget the lessons of history - majestically inscribed into the paleontological and geological record - are doomed to repeat it. Educate yourself, become politically active, and force our leaders to change course before an anthropogenic apocalypse devours us all.
Other excellent books on global warming include Storm World: Hurricanes, Politics, and the Battle Over Global Warming by Chris Mooney, With Speed and Violence: Why Scientists Fear Tipping Points in Climate Change by Fred Pearce, Six Degrees: Our Future on a Hotter Planet by Mark Lynas, and Field Notes from a Catastrophe: Man, Nature, and Climate Change by Elizabeth Kolbert.
A More Dangerous Result of Global Warming!
Global warming, contrary to some, is pretty much a done deal, at least with a 90% certainty. Yes, there is a 10% possibility that it is not happening, or that humans are not the main cause, but who wants to bet on 9 to 1 odds, especially when there is a high chance of catastrophe?
It amazes me that there are still some people who deny that the process is occurring or that it is to a large extent human caused. Some go so far as to ascribe the whole idea to a secret plan to increase the use of nuclear power! But the evidence for global warming keeps piling up, despite their views. As a biologist I have observed the creep ahead of the seasons even in the temperate zone, and the Arctic is having an even more marked change. Numerous studies have linked the rise in temperature primarily to human carbon dioxide production.
Peter D. Ward is a professor of biology and earth and space sciences at the University of Washington in Seattle. While studying the mass extinctions of the past, especially the Permian-Triassic, the Triassic-Jurassic and the Paleocene-Eocene, he and his associates have turned up an even greater threat of global warming- the release of toxic gases from the oceans.
In "Under a Green Sky: Global Warming, the Mass Extinctions of the Past, and What they Can Tell Us About Our Future" Ward outlines the causes of these major extinctions. Once thought to all have occurred because of asteroid strikes, these extinctions were quite different from the Cretaceous-Paleocene event, which apparently was triggered by such a cosmic calamity. Now the three are more probably connected to naturally occurring high carbon dioxide and methane levels, leading to the melting of polar ice caps, the shutting down of the oceanic conveyor system, and the proliferation of sulfur bacteria in anoxic oceans. This is ominous, given our current rise in greenhouse gases, as the oceans then rose to cover the shore far inland in low lying areas and the atmosphere turned poisonous.
If Ward is right we are in deep trouble. He just might be wrong, but it would be folly not to pay attention! Everyone should read this book or something like it. It might change your thoughts on the subject.
