Review: Under A Green Sky

You should not read this book.

I mentioned last week that I had started reading Peter Ward's Under a Green Sky: Global Warming, the Mass Extinctions of the Past, and What They Can Tell Us About Our Future. Here's what I wrote:

I have a feeling that the "Global Warming" part of the subtitle was tacked on at the publisher's request, since halfway through it has mostly been an exploration of the different varieties of mass extinctions that have taken place in Earth's history.

You've probably heard about the asteroid that wiped out the dinosaurs. But truth is, prior to Luis and Walter Alvarez's discovery in 1980 of the iridium layer that provides evidence of an extraterrestrial impact consistent with the end of the Age of the Dinosaurs, this was just another theory floating around. But it took off. And soon every mass extinction - and there have been a few, where a significant proportion of living things on Earth and under the oceans have died off - was being blamed on asteroid impacts. Even though there was no evidence for them, no telltale iridium layers or smoking craters, save the one that hit some 65 million years ago and within a few years or decades brought down the saurian rulers of the Earth.

Ward carefully presents the evidence for other causes, all sewn together in an exciting narrative that presents a behind-the-scenes look at the jealousy, pettiness, cutthroat competition, and downright danger experienced by those who would solve these mysteries. And he dispels the notion that this is a world made for us; indeed, he puts forth various evidence-backed versions of Earth's past environment that were inimical - and deadly - to almost all forms of life.

I'm not done yet. I only made it about halfway though, and the badly-written and -acted soap operas chattering over my shoulder this afternoon made it hard to focus.* But I think I'm just getting to the good parts, where various toxic gasses tied up in the oceans are belching forth and doing really bad things to the environment.

I've mentioned tipping points before. Turns out that when I wrote this post, I was at the tipping point of this book.

You should not read this book.

There are those who dismiss concerns of climate change by referring to the proponents of this idea as AGW Alarmists. It took me a few seconds to work out what those letters stand for. They stand for Anthropogenic Global Warming - global warming brought on by the actions of humans. Some of them would certainly label paleontologist Peter Ward an AGW Alarmist.

In this book I will marshal a history of discovery, beginning in the 1970s, that has led an increasing number of scientists across (a) broad swath of fields to conclude that the past might be our best key to predicting the future. As strewn across this barren, nearly lifeless hillside in the nontouristy middle of Nevada, if there is even the slightest chance that the carbon dioxide in Earth's atmosphere of 200 million years ago caused this mass extinction, as well as the numerous other times before and since that ancient calamity, then it is time for we practitioners who study the deep past to begin screaming like the sane madman played by Peter Finch in the classic 1976 film Network, who brought forth his pain with the cry: "I'm mad as hell, and I'm not gonna take it anymore."

In our case, this cry must be: "I am scared as hell, and I am not going to be silent anymore!"

This book is my scream, for here in Nevada, on that day when heat was its usual quotidian force of death, we sat on the remains of a greenhouse extinction, and it was not pretty, this graveyard, the evidence clutched in the dirty rocks utterly demolishing any possibility of hyperbole. Is it happening again? Most of us think so, but there are still so few of us who visit the deep past and compare it to the present and future. Thus this book, words tumbling out powered by rage and sorrow but mostly fear, not for us but for our children - and theirs.

(Introduction, pages xiii - xiv)

Is Peter Ward an AGW Alarmist? He might consider that term to be putting it mildly.

You should not read this book.

As I described above, Ward takes us through the recent history of the determination of the causes of past global extinctions. One - and only one - extinction is known to have been caused by an extraterrestrial impact. Other extinctions show evidence of different causes, or more precisely, the same different cause. It's nothing quite so simplistic as "the world got too hot for things to live." No, the mechanism is a bit more horrible than that.

The story usually starts with volcanism. Earth is a geologically active planet, which is a nice thing, because without a source of heat inside our planet things the history of life would be would be very different. Non-existent, really; Earth's distance from the sun is too great to maintain liquid water just as a result of direct solar radiation.

Oh, not that the heat from our core is enough to do it, either. Not by itself. Thermally speaking, without any other factors coming into play, Earth would be an iceball with some liquid water at the lowest reaches. There is evidence that it has been, actually, several times.

Ah, but our geologically active planet has volcanoes. Volcanoes which periodically erupt in large numbers, and pour blessed greenhouse gasses like carbon dioxide into our atmosphere. It is through the heat-trapping function of these gasses, called the greenhouse effect, that our planet is warm enough to support liquid water - and life.

But you can have too much of a good thing. I won't try to restate Ward's thesis - he sums it up pretty plainly in Chapter 6, "The Driver of Extinction," on page 137 of my softcover.

First, the world warms over short intervals of time because of a sudden increase in carbon dioxide and methane, caused initially by the formation of vast volcanic provinces called flood basalts. The warmer world affects ocean circulation systems and disrupts the position of the conveyor currents. Bottom waters begin to have warm, low-oxygen water dumped into them. Warming continues, and the decrease of equator-to-pole temperature differences reduces ocean winds and surface currents to a near standstill. Mixing of oxygenated waters with the deeper, and volumetrically increasing, low-oxygen bottom waters decreases, causing ever-shallower water to change from oxygenated to anoxic. Finally, the bottom water is at depths where light can penetrate, and the combination of low oxygen and light allows green sulfur bacteria to expand in numbers and fill the low-oxygen shallows. They live amid other bacteria that produce toxic amounts of hydrogen sulfide, and the flux of this gas into the atmosphere is as much as 2,000 times what it is today. The gas rises into the high atmosphere, where it breaks down the ozone layer, and the subsequent increase in ultraviolet radiation from the sun kills much of the photosynthetic green plant phytoplankton. On its way up into the sky, the hydrogen sulfide also kills some plant and animal life, and the combination of high heat and hydrogen sulfide creates a mass extinction on land. These are greenhouse extinctions.

Not good. Not pleasant. And a scenario which has been repeated multiple times in the Earth's history.

But, the thing is, geological evidence indicates that there was usually an incident of mass volcanism that brings on this nastiness. Volcanoes belching methane and carbon dioxide into the air. But, despite a few rumblings here and these, there are no indications that the Earth is on the verge of experiencing any mass volcanism incident.

Humans have built their own volcanoes.

We are belching our own greenhouse gases into the atmosphere. From smokestacks and tailpipes, herds and paddies, field-clearing fires and irrigation floods, we are engaging in unprecedented acts that are generating greenhouse gases, and rapidly increasing atmospheric greenhouse gas concentrations to levels not seen in eons.

So what now? What next? What is Ward's plan from saving us from this looming disaster?

(You should not read this book.)

Well, that's the kicker, kiddies: he doesn't have one. Peter Ward isn't writing this book as a savior. He isn't really a Prophet of Doom, though that's the overall effect. He's a scientist describing findings of the paleontological past and applying them to the future. The fate outlined above, barring another asteroid strike, appears to be inevitable; it is a mechanism that has played out over and over again in Earth's past. But it's a question of when - or at least it was. For now there is no longer any need to wait for volcanoes to push the system over the edge. We're doing it ourselves. Have been doing it. Maybe have done it. It may very well be too late to do anything about it. It may have been too late for the last 30 years, or since the Industrial Revolution. It may have been too late since humans tamed fire and developed agriculture.

Is there any hope?

"Without hope there will be no action," Ward writes on page 192.

As far as can be seen in the present, we have not yet reached the point of no return, or the tipping point. We as a worldwide society can keep carbon dioxide levels below 450 parts per million. If we do not, we head irrevocably toward an ice-free world, which will lead to a change in the thermohaline conveyor belt currents, will lead to a new greenhouse extinction. The past tells us this is so.

This is written at the end of Chapter 9, "Back to the Eocene." The chapter that was supposed to end the book.

You should not read the next chapter, called "Finale."

You should not read this book.

You should not read it if you like to sleep at night, to dream of the future. You should not read it if you have children or plan to have children. You should not read it if you commute 66.6 miles a day in a 1996 Toyota Tercel that gets 35-40 mpg or if you ride a bicycle to work. You should not read this if you'd ever like to stare out at the ocean again and not think about the doom that will someday come from its bottom.

So why am I here, writing this? Why am I not sitting in an alley somewhere, a blanket wrapped around myself, with a sign reading "NO HOPE / NO FUTURE" hanging around my neck?

Honestly, I don't know. In time the strongest effects of this book may wear off, and I'll be able to return to my painting, my photography, my gardening. Maybe tomorrow. There are bills to pay, blogs to read.

Some may take the inevitability of the oncoming disaster as a license to do what they wilt. I don't really have a good argument against that. But we're not there yet. Maybe we'll be able to avoid the tipping point for another century. Maybe if every person in the world abandons their cars tomorrow, maybe if every factory in the world shuts down tomorrow, maybe if 90% of the Earth's population disappears tomorrow, we'll have a little more time than that. And maybe in that time somebody will notice something that has been overlooked, some key that will allow us to avoid rushing headlong into the disaster. Maybe.

Maybe you should read this book.


Image taken from the HarperCollins website.