Please enjoy this excerpt of Deep Future: The Next 100,000 Years of Life on Earth by Curt Stager, out now from Thomas Dunne Books. The book takes a realistic look at the effects that current global warming will have for our planet’s long-term climate.
We face a simple choice in the coming century or so; either we’ll switch to nonfossil fuels as soon as possible, or we’ll burn through our remaining reserves and then be forced to switch later on. In either case, green house gas concentrations will probably peak some time before 2400 AD and then level off as our emissions decrease, either through purposely reduced consumption or fossil fuel shortages. The passing of the CO2 pollution peak will trigger a slow climate “whiplash” in which the global warming trend will top out and then flip to a long-term cooling recovery that eventually returns temperatures to those of the preindustrial eighteenth century. But that process will last for tens or even hundreds of thousands of years. The more fossil fuel that we end up burning, the higher the temperatures will rise and the longer the recovery will take.
There’s much more to CO2 pollution than climate change, though. Carbon dioxide will gradually acidify much or all of the oceans as they absorb tons of fossil fuel emissions from the air. That chemical disturbance threatens to weaken or even dissolve the shells of countless corals, mollusks, crustaceans, and many microorganisms, and their loss, in turn, will threaten other life-forms that interact with them. In some ways, this situation resembles the contamination of the primordial atmosphere by microbial marine oxygen, only in reverse; we are responding 2 billion years later with a corrosive gas of our own that is moving from the air back into the sea. Eventually, the neutralizing capacity of Earth’s rocks and soils will return the oceans to normal chemical conditions, but the acid-driven loss of marine biodiversity will be among the most unpredictable, potentially destructive, and irreversible effects of Anthropocene carbon pollution.
Before the end of this century, the Arctic Ocean will lose its sea ice in summer, and the open-water polar fisheries that develop in its absence will last for thousands of years, radically changing the face of the far north as well as the dynamics of international trade. But when CO2 concentrations eventually fall enough, the Arctic will freeze over again, destroying what will by then have become “normal” ice-free ecosystems, cultures, and economies.
Much or all of Greenland and Antarctica’s ice sheets will melt awayover the course of many centuries, with the final extent of shrinkage dependent upon how much green house gas we emit in the near future. As the edges of today’s icy coverings draw back from the coasts, newly exposed landscapes and waterways will open up for settlement, agriculture, fishery exploitation, and mining.
Sea level will continue to rise long after the CO2 and temperature peaks pass. The change will be too slow for people to observe directly, but over time it will progressively inundate thickly settled coastal regions.Then a long, gradual global cooling recovery will begin to haul the waters back from the land. But that initial retreat will be incomplete, because so much land-based ice will have melted and drained into the oceans. At some time in the deep future, the sea surface will come to rest as much as 230 feet (70 m) above today’s level, having been trapped at a new set point that reflects the intensity and duration of the melting. Only after many additional millennia of cooling and glacial reconstruction will the oceans reposition themselves close to where they lie now.
We have prevented the next ice age. The ebb and flow of natural climatic cycles suggests that we should be due for another glaciation inabout 50,000 years. Or rather, we used to be. Thanks to the longevity of our green house gas pollution, the next major freeze-up won’t arrive until our lingering carbon vapors thin out enough, perhaps 130,000 years from now,and possibly much later. The sustained influence of our actions today on the immensely distant future adds an important new component to the ethics of carbon pollution. If we consider only the next few centuries in isolation, then human-driven climate change may be mostly negative. But what if we look ahead to the rest of the story? On the scales of environmental justice, how do several centuries of imminent and decidedly unwelcome change stack up against many future millennia that could be rescued from ice age devastation?
You and I are living in a pivotal moment of history, what some have called a “carbon crisis”— a crucial and decisive turning point in which our thoughts and actions are of unusually great importance for the longterm future of the world. But all is not yet lost, and climate change is not on the list of deadly dangers to most humans; as I will explain later, Homo sapiens will almost certainly be here to experience the environmental effects of the Anthropocene from start to finish. And that’s only fitting, seeing as we’re the ones who launched this new epoch in the first place.
But why, then, should we care enough about the distant futureeven to finish reading about it on these pages? The reason is simple. Although humans will survive as a species, we are faced today with the responsibility of determining the climatic future that our descendants will live in. It may well be a struggle to hold our carbon pollution to a minimum,but 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 the likes of which haven’t been seen on Earth for millions of years. And the outlook for most nonhumans is far more worrisome than it is for our own kind. Severe environmental changes have happened before, even without our influence in themix, but the situation that we and our fellow species now face is unique in the history of this ancient planet.
So welcome to this glimpse of our deep future. Welcome to the Anthropocene.
From Deep Future by Curt Stager. Copyright © 2011 by the author and reprinted by permission of Thomas Dunne Books, an imprint of St. Martin’s Press, LLC