Under a Green Sky: Global Warming, the Mass Extinctions of the Past, and What They Can Tell Us about Our Future

I've always liked Peter Ward's work because he can write, and it's interesting stuff. This one is also terrifying, arguing believably that Earth has been poisonous to our kind of life. And could be again. It reminds me of paleontological/oceanic horror by Caitlin Kiernan or Peter Watts, only they write fiction, and this is not. The book is not only well-written but reads to me like good science, although I freely confess I don't get all the chemistry involved. Ward cites and summarizes a lot of research done by others as well as himself. And it's not just a political screed -- in fact it really isn't one in structure and tone, although since global warming/greenhouse gases cause the deaths... it makes its point.

The last 2 chapters of this book read like a depressing work of sci-fiction. I still have a hard time believing that temps are probably going to rise to levels not present on Earth since the Eocene. And in an eye-blink. Read Ward's book (especially his short interview w/ a climate scientist at the U of Wash who looks into the melting crystal ball), and follow it with a stiff shot of James Lovelock's latest release, The Revenge of Gaia, which has come down in price considerably.

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 fi

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.

This book could be divided into two parts. The first part is a scientific analysis of the possible causes for the great mass extinctions that have occurred over the past hundreds of millions of years. The second part makes use of the findings of the first part to speculate on what might happen to the earth (and to us) over the next few years, decades and centuries. Contrary to the common belief of a few years ago that mass extinctions were all caused by impacts with bolides from outer space, it now appears that most of the great mass extinctions (other than the K-T extinction) are likely to have been due to the accumulation of greenhouses gases in the earth's atmosphere. After explaining how this was discovered, the author explains the mechanics of how atmospheric greenhouse gases increased in the distant past, along with the disastrous effects on life that existed on earth and in the oceans at the time. He compares the carbon dioxide concentrations of the distant past with those of today with projections of what they might become in the future. The author's writing style is quite clear, friendly, authoritative (he is a paleontologist) and very gripping. I found this book very hard to put down. Although there is much speculation in the second part of the book, one can only wonder. This book should be of interest to general readers, but science buffs may get the most out if it due to the many fascinating scientific discussions.