Deep Future The Next 100,000 Years of Life on Earth

Most books on climate begin with the last couple of centuries—the Industrial Revolution and the onset of massive emissions of carbon dioxide—and then move to what remains of the twenty-first century. In Deep Future, Curt Stager looks at millennia, thousands of millennia, back toward the very origins of life and forward for over a hundred thousand years.

Stager is a professor at Paul Smith’s College and a paleoecologist; he studies ancient environments, through pollen samples, fossils, and other vestiges of past life. This gives him the “long view,” an understanding that over vast eons, life on earth and the environment that supports it are always changing. His goal in Deep Future “is to introduce us to a broader perspective on global warming than the one most readers are familiar with.”

It’s a troubling book. First, because it lays out in convincing, dramatic detail the profound ways that human activity is changing and will continue to change, far into the distant future, our planet’s climate. Stager adopts a term becoming widespread among scientists to label the era we are now in and will be in for many millennia, the Anthropocene, to emphasize the unprecedented human impact on the global environment. In addition to altering the climate, human activities have precipitated a devastating loss of biodiversity and the introduction of incalculable quantities of poisons into our air, water, and soils.

Troubling also because, thoughtful as it is, the book addresses a complex issue—the inevitability of climate change and how we should think about it—in ways that strike me as a bit facile and thus subject to manipulation by fossil-fuel interests and their mouthpieces like Oklahoma Senator James Inhofe and Rush Limbaugh.

Stager devotes much attention to examining what warming trends were like in the distant past, during epochs when the earth’s slightly wobbly orbit or other factors led to warming: for instance, he gives us a detailed picture of the Eemian, an interglacial period that preceded the last ice age, ending about 117,000 years ago. Evidence from ice cores and other research shows that much of northern Europe was then under water, the Arctic Ocean was seasonally ice-free, and rain fell in biblical deluges. If we were to stop using fossil fuels today, minimizing the wholesale introduction of CO2 into the atmosphere, we might expect, in a century or two, a level of warming roughly analogous to what occurred in the Eemian. If we maintain or even ramp up our consumption of fossil fuels, we can expect an even hotter planet.

If you go back further, to about 55 million years ago, you can find a period of warming equal to the worst-case scenarios for the Anthropocene. In that ancient time, the level of CO2 in the atmosphere was roughly equal to what would be the case if we burn all the remaining coal and oil on the planet. The result of that elevated CO2 was acidified, brackish oceans, virtually no ice or snow anywhere, and mass extinctions.

Deploying his encyclopedic grasp of the vast reaches of terrestrial history, Stager runs through a depressing litany of what our distant descendants can expect—not necessarily in the next generation or two, but eventually. One inevitable consequence of warming will be acidified oceans. CO2 absorbed by the ocean becomes carbonic acid, which in turn corrodes the shells of living sea creatures, including crabs, oysters, and lobsters; coldwater corals will also suffer. This process has already begun and will continue for centuries. The only question is how awful it will get: bad if we exercise restraint and start weaning ourselves from coal and oil, apocalyptic if we don’t. “Ocean acidification represents one of the most compelling reasons to control our emissions, not only for ourselves but for the sake of countless other species that share this water-dominated planet with us.” Mass extinctions anywhere in the complex marine food chain would have catastrophic consequences.

Not only will the oceans be acidified, they will also be higher, under either scenario. Change will be slow and barely noticeable, but by 2100, the world will look different, and many millions of people, probably hundreds of millions, will have been displaced. The Arctic Ocean will be ice-free in the summer. Stager carefully examines all the evidence and trends with respect to polar bears, an emblematic species because climatechange skeptics claim they are not in decline. Stager finds otherwise and sees little hope for their long-term survival. Ditto for walruses. Equally important, communities of little critters like sea urchins, clams, and sea cucumbers are “disappearing along with the ice.” Diseases from warmer waters, such as distemper and brucellosis, are creeping into the Arctic, threatening belugas and narwhals. On land and in the sea, species will disappear, many to be replaced by species moving up from the south. Mosquitoes are now found in parts of the Arctic where they were never seen before.

And so it goes: Greenland will probably be ice-free by 5000 A.D. In the tropics, where precipitation is much more important than temperature, rainfall will be erratic; regions where it is now abundant and where it supports agriculture will be dry.

When Stager contemplates the meaning of all this, he ventures into turbulent waters: If change has always defined the reality of our planet’s climate, he asks, why should we be concerned with the fact that the climate is changing now? There have been mass extinctions before—seen a dinosaur lately?—and it’s certain there will be others in the future, whether we’re around to see (or cause) them or not. What’s the difference? After all, an extinction is an extinction, right? And they’ve been happening for billions of years.

The planet’s first “global pollution crisis was actually the work of marine bacteria, and it struck just over 2 billion years ago at a time when all life on Earth was single-celled,” Stager writes. Photosynthesis released vast quantities of oxygen into the air; most species of bacteria couldn’t handle it and died off. Later (much later!), this enabled the rise of mammals, including us, a class of creatures that could not have evolved in the primordial, oxygen-poor atmosphere of that long-ago, single-celled age. Change happens, he shows, and it’s not necessarily a bad thing. “When the world changes so dramatically, there must always be winners and losers. In this case, we have clearly been among the winners.”

Another reason that Stager does not despair about the reality of a warming planet involves the cycles of ice ages. We’re currently in an interglacial period, which allows our human culture to thrive. Sooner or later, under normal circumstances, it would end and ice sheets would completely cover much of northern Europe and North America. The last ice age covered the north for about a hundred thousand years and ended only twelve thousand or so years ago. But because of the CO2 already introduced into the atmosphere by our relentless use of fossil fuels, “we have prevented the next ice age,” which otherwise would have arrived about fifty thousand years from now.

So, he asks, shouldn’t we consider the favor we’re doing our distant descendants? Suffering in the short run may mean rescuing the world from an ice age. “At first, this … might seem outlandish, a silly kind of joke.… It also feels like tossing red meat to the habitual contrarians who seek any excuse to avoid controlling fossil fuel consumption. But the facts are plain, and I believe they’re worth considering carefully.” Indeed, one reason for cutting back on our use of fossil fuels, he argues, is to leave some coal for future generations to burn if they want to prevent a far-off ice age.

If we in the twenty-first century burn all the coal and oil, moreover, we’ll create a climate regime far too warm for civilized life: “failing to take the heroic path and control our collective behavior is likely to drag us and our descendants into a realm of extreme warming, sea-level rise, and ocean acidification that hasn’t been seen on earth for millions of years.” That’s his argument: a little warming isn’t so bad, but a lot will be catastrophic.

“Climate change is a troubling and complex issue, but it’s not going to kill us all off.” For me, that “all” is disturbing: droughts, floods, and famines can and surely will kill many millions of us, even if not many affluent North Americans. And there is more to fear than uncooperative weather. In Climate Wars (2010), Gwynne Dyer takes a hard look at the geopolitical consequences of global warming. To cite just one example of the likely troubles ahead: the Indus River, fed by Himalayan glaciers, supplies water to and supports agriculture for hundreds of millions of people in India and Pakistan. Ponder for a moment what might happen when shrinking glaciers no longer release enough water to satisfy both of those nuclear-armed nations.

Stager is looking for middle ground, between extreme climate change and shaking the fossil-fuel addiction immediately, which he sees as impossible. For him, the long view makes the future look less threatening than, say, the predictions we find in recent books by Bill McKibben (Eaarth, 2010) and Jerry Jenkins (Climate Change in the Adirondacks, 2010), but I find his reassurances unconvincing. It’s true, of course, that change is inevitable and that to pretend that we can keep our environment in some perfect state of equilibrium is delusive. But I fear that his emphasis on the long view only serves the interests of those who want to do nothing. That’s clearly not his intent. But I shudder to think how Rush Limbaugh might interpret this book.