Fossil Skies: Were the Planet's Past Extinction Events Caused by Global Warming?

“If you look at the fossil record, it is just littered with dead bodies from past catastrophes,”  observes University of Washington paleontologist Peter Ward. Ward says that only one extinction in Earth’s past was caused by an asteroid impact – the event 65 million years ago that ended the age of the dinosaurs. All the rest, he claims, were caused by global warming.

Ward's Under a Green Sky explores extinctions in Earth’s past and predicts extinctions to come in the future.

Ward demonstrates that the ancient past is not just of academic concern. Everyone has heard about how an asteroid did in the dinosaurs, and NASA and other agencies now track Near Earth objects. Unfortunately, we may not be protecting ourselves against the likeliest cause of our species' demise. Ward explains how those extinctions happened, and then applies those chilling lessons to the modern day: expect drought, superstorms, poison–belching oceans, mass extinction of much life, and sickly green skies.

The significant points Ward stresses are  geologically rapid climate change has been the underlying cause of most great "extinction" events. Those events have been, observed Harvard evolutionary biologist Stephen Gould, major drivers of evolution. Drastic climate change has not always been gradual; there is solid empirical evidence of catastrophic warming events taking place in centuries, perhaps even decades. 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. 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, it appears to have the potential for catastrophic effects within a lifetime or two.

Ward's prior 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. Under a Green Sky recapitulates some of that hypothesis and the evidence to support it.

As a prominent paleontologist, Ward is well positioned to point us 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, 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 more or less complementary. Both have radical implications for the current Darwinian model of evolution. Both have alarming implications for the near-term future of humankind.

Looking at the ancient evidence, Ward notes that ice caps began to shrink. "Melting all the ice caps causes a 75-meter increase in sea level will remove every coastal city on our planet." It will also cover earth's most productive farmland, the author warns, adding, "It will happen if we do not somehow control CO2 rise in the atmosphere."

Ward sees positive signs in the fight against global warming. "Most people are now educated as to what it is and most everyone knows that it has to do with carbon dioxide and that we have to slow that down. There is half the battle right there."

Ward is encouraged that we are beginning to make changes in their daily lives and demanding action from their leaders -"that we are on a planet that has violent convulsions, and that we humans are playing with nature in such a way that we could recreate what were some really awful times in earth's history, that we really tinker with the earth's atmosphere at our peril."

Posted by Casey Kazan.

Related Galaxy posts:

The Great Debate: How Fast Will Sea Levels Rise?
The Andes Vanishing Glaciers
The Day the Seas Died: What Can the Greatest of All Extinction Events Teach Us About Climate Change?
The Timeline For 21st Century “Climate Change Events”
Coming of Age in the Holocene
"Snowball Earth" Challenged
Bigger Threat than Global Warming -Mass Species Extinction
A "Flat World" Solution to Climate Change
Monitoring Climate Change -Experts Say We Need Lunar Observatories
Unraveling the Mysteries of -Clues to Climate Change on Earth?
Arctic Discovery –Ancient Connections & the Global Climate
Stephen Hawking: Climate Change Greatest Threat Facing Planet
Arctic’s Legendary Northwest Passage is Ice-Free for the First Time in Recorded History
Coming War for the Arctic?

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Comments

[Scott Smith]

Maybe Dr Stephan Hawking was correct, maybe it is time, in light of various serious risks to the survival of humanity here, that earth humans seek an "interstellar relocation" as a larger over reaching solution. Maybe less war, and re-allocation of those funds to humanities R&D would serve the global collective best at this time.

[Dennis]

Perhaps we should try for interplanetary first :-)

And good luck with the rest of that. When we have people having screaming hysterics at the thought of (horror of horrors) being forced to reconsider their lightbulb purchases, I don't think the rest of that is going to be met with exclamations of joy.