Review of Deep Future: The Next 100,000 Years Of Life On Earth by Curt Stager

I’ve always held that the Sun is out to get us. Oh, sure, it plays the role of life-giver, showering the Earth in energy and heat necessary for life. Yet too much time in the Sun leaves us open to cancer. And in a little under five billion years, the Sun, in its senescence, will expand to engulf our planet. Before that happens, however, its expansion will have already scorched the surface and rendered the Earth uninhabitable. So pack your bags now, people. We might have as little as a billion years left!

If that sounds crazy, well, fine. But I really enjoy science fiction that considers the concept of human survival into the far-far-future. For one thing, it’s optimistic, because it assumes that we survive this tumultuous age. And then it asks: what happens to humanity when the Earth can no longer support life? What happens to humanity when the Andromeda and Milky Way galaxies collide? What happens to humanity when the very universe itself ends? These events are almost impossible to fathom from our limited, terrestrial perspective. They have no bearing on our present-day lives. Yet they are fascinating to consider.

Curt Stager doesn’t look quite so far ahead in Deep Future: The Next 100,000 Years of Life on Earth. However, the sentiment is similar. He discusses global warming and greenhouse gases from a longer-term perspective than the topics usually receive in most media. Stager isn’t interested in how warming trends will affect the Earth into the next century or even the next millennium; instead he goes several orders of magnitude beyond. Central to this discussion is his argument that we, this generation, this century, have the opportunity to influence the next 100,000 years, depending on how much of our fossil fuels we leave in reserve and how much we manage to curb our carbon emissions.

The Earth is warming. The scientific consensus is in. This consensus includes a determination that humans are the primary culprits of this warming, thanks to our newfound skills at digging up dead plant life and burning it in offering to the gods of power and propulsion. For the first time in the history of the Earth, a species has managed to alter the biosphere of our planet through deliberate action. That’s rather staggering. (Stager introduced me to the term Anthropocene, a proposed new geological era corresponding to humans affecting the environment on a global scale.)

Denial of global warming is, thankfully, shrinking—but there are still plenty who, while acknowledging the fact, practise cognitive dissonance in claiming that global warming is either (a) not that much of an issue or (b) not this generation’s problem. Those with economic interests in maintaining our dependence on oil, coal, and natural gas claim that switching to alternative fuels is impractical or even impossible. Those who favour such a switch claim we’re selling our descendants of the next century up the river.

Stager points out that few people on either side of this debate consider what will happen to humanity and Earth beyond a century or two hence. And he has a point. The carbon cycle is such that our carbon emissions don’t affect the warming and cooling trends for the planet just into the next century or two; these emissions will affect warming and cooling for the next hundred millennia. So it behoves us to consider our actions on such a timescale, as incomprehensible as that might seem at first. So with Deep Future Stager aims to present some of the possible consequences if we either tamp down our emissions to a "moderate" level or continue to burn through our reserves as aggressively as possible.

The book treats us to visions of the past and the future, as Stager examines evidence of the former’s warming and cooling trends to help prognosticate possibilities for the latter. Past temperatures are available to us through ice core and sediment core samples, while future temperatures are the realm of advanced computer models. Stager is careful to attach a caveat when discussing the results of models: climate modelling, though distinct from weather modelling, remains quite difficult to get right. In some cases the timing might be off even when we are confident of the actual consequences.

Perhaps one of the most interesting contentions of the book is that our descendants might intentionally burn any remaining fossil fuels to ward off the next ice age. For this reason, Stager argues, we might want to consider leaving some around. I find this idea fascinating because it perfectly describes the Anthropocene; as time goes on, we are increasingly going to need to make more conscious decisions about how to alter our biosphere. It also demonstrates another idea that recurs throughout the text: "warming" doesn’t necessarily equal "bad".

To be sure, the current warming is having and will continue to have adverse effects on society, industry, and infrastructure. Yet change is inevitable. Only a billion years ago, the idea that there would ever be this much oxygen in the atmosphere would have seemed absurd to any life on Earth capable of such considerations. But thanks to some enterprising early bacteria mastering the art of photosynthesis, we’re now a planet dominated by oxygen-breathers, with our anaerobic distant cousins squatting in oxygen-deprived hovels deep in the ocean, shaking their metaphorical fists at us. Thus, there is precedent for life on Earth altering the atmospheric makeup and very environment of the planet. And life will adapt, as it always does, and flourish—with or without humans present.

This is Stager’s assertion. Other reviews call Deep Future an optimistic book, and indeed, Stager seems pretty sanguine about humanity’s chances of survival millennia from now. He’s careful to qualify that as the survival of the species, and that’s an important distinction. It’s very easy to discuss how global warming will be socially disruptive in the next century or so. Naturally, it’s harder to predict how society will change in response to continued warming over the next millennium. But aside from a few catastrophic scenarios, Stager opines, it will be very difficult for all of humanity to go extinct, even if civilization as we know it collapses again.

In this respect I think Stager is being too quick to dismiss those possible catastrophes. True, he’s engaging in speculative science rather than speculative fiction. I’m not expecting him to consider grey goo or a Singularity as possible apocalyptic events. Yet our continued tinkering with genetics, the ease with which we spread disease, etc., presents a host of opportunities for us to hasten our extinction.

On balance, though, Stager’s probably right. Civilization might end, but humans will endure. So Deep Future is an attempt to provide a glimpse at what the Earth might be like for these survivors. Using the latest techniques in climate modelling, Stager attempts to demonstrate how two different scenarios for human-caused warming will change the face of the planet. It’s an impressive education in how we affect our environment and an important reminder of how much every aspect of life on Earth is inextricably bound together. From the carbon cycle to the water cycle, all these processes conspire—sometimes over geological time-scales—to produce the most amazing changes. When Stager talks about how the weight of the ice on Greenland will actually create new, massive fjords as the glaciers melt … that’s just a "whoa" moment. Geology is cool.

Stager’s dedication to being even-handed, neither alarmist nor reactionary, in his presentation will doubtlessly frustrate or even infuriate readers on either side of the issue. Those who accept the scientific consensus that human-caused warming is a pressing issue, myself included, might wish that Stager were not so sunny in his outlook. But that’s missing the point. There is plenty of literature talking about the present crisis we face, and it’s an important subject. But it’s not the only way to view the issue of global warming, and with Deep Future, Stager reminds us of that. It’s important that we don’t forget that warming itself is not the bad thing, carbon dioxide itself is not the bad thing; rather, it’s the intensive, runaway warming that we’ve caused that is the problem.

We’ve passed the point where we can just throw up our hands and claim that we don’t have an impact on the environment. There is no going back. The only thing to do now is to accept our stewardship of the planet Earth and try to determine how best we can influence the next 100,000 years, for our own species and all the others here on planet Earth.