However, recent climate science has shown definitively two fundamental facts. The first is that the rate of increase of greenhouse gases in the atmosphere is unprecedented, perhaps in the entire geological history of the earth, and that such atmospheric shifts have in the past always resulted in a radically changed climate on the earth. The prospects are alarming: should humans burn all remain fossil fuels over the course of the next couple of hundred years (or if warming of the arctic tundra incites a feedback mechanism releasing large amounts of methane), then absent some radical carbon sequestration or geoengineering, CO2 atmospheric carbon levels will reach levels that have not been seen since the Eocene (~50 million years ago) – when sea levels were 150 feet higher and palm trees shaded crocodiles on Alaska’s North Slope.
The second important recent scientific discovery is that the climate stability of the last five or six millennia is in fact relatively unusual. During many phases of the last two hundred thousand years since homo sapiens emerged there have been wild swings in the climate from century to century or even decade to decade. Despite this history, however, scientists (including the IPCC scenarios) tend to forecast incipient climate change as a steady, continuous (albeit perhaps rapid) ascent to a hotter and more hydrologically active Earth. We see this in innumerable steadily upward sloping curves that show increases in carbon load, temperature, rainfall, and so on. Only rarely is it considered that in fact the lived human experience of these changes may be something quite different.
In meteorological terms, it may be reasonable to depict climate change as a steady progression towards a warmer Earth. In fact, the lived human experience of climate change is likely not to be one of steady continuous change, but rather will take the form of a series of bone-jarring discontinuities: climate change will be experience as a series of sudden "events" that radically destabilize existing physical infrastructure, political institutions, and human lives, in each case producing sudden phase shifts from one state to another, akin to the physical shift that H2O experiences at 0°C from ice to water, or at 100°C from water to vapor. Stewart Brand quotes me on this point in his new Whole Earth Discipline:
"While a single extreme event may be relatively easy to withstand, a second in succession is likely to be far more devastating, as normal resiliency measures are built to deal with one but not multiple consecutive extreme events." Governments, [Gilman] concludes, "will experience climate change not as a smooth transformation, but rather as a series of radical discontinuities—as a series of bewildering 'oh shit' events. Environmentally failed states are a nontrivial possibility."The severity and rapid succession of these weather events are likely to test the systems that support our nations like nothing we have seen in modern history.
In fact, not only at the first-order level of changes to the weather, but also (perhaps even more so) at the level of second order impacts, the changes being wrought on by global climate are likely to take the form of abrupt, phase shifts. For example, at the first-order level of the weather, a coastline may remain more or less stable and constant for decades, and then suddenly and permanently shift abruptly back by hundreds of meters in the aftermath of s single massive storm surge. At the second-order level, likewise, a civilization may remain more or less stable, even in the face of repeated weather-related crisis, before finally tipping over into full-blown collapse. As Brand explains:
Repetition knocks you down; duration kills you. Complex societies can handle drought, but not multi-decade drought. That's the historic civilization killer, says archaeologist Brian Fagan. It brought down the ancient empires of West Asia and Central America. When the rains fail, agriculture fails, the cities convulse and empty, and what’s left of the society builds shacks in the ruins of its former glory. In this century the effects of rising sea levels, catastrophic as they may be, could look temporary and fixable compared to the effects of permanent drought.If one sort of cognitive bias is to assume that climate change will be experienced as a steady, progressive event, then an equally pernicious cognitive error is to assume that the impact of climate change will be sudden and extreme, involving the total collapse of human civilization virtually overnight, such as that depicted in the (alas, quite silly) movie “The Day After Tomorrow”. As with the previous sort of cognitive error, this view does contain a kernel of truth, as a corrective to the cognitive bias that assumes that climate change will be a smooth, gradual process, one that will give individuals, corporations, and governments plenty of time to plan and adjust. However, the image of human civilization flipping wholesale from our currently allegedly stable climax state to a globally synchronized civilizational collapse is deeply misleading, at two levels.
In the first place, as population ecologists have long known, collapse usually is not an overnight event where a population moves from a climax state to total annihilation. Rather, collapse more typically happens as a phased process, taking the form of what be might described, to invert the phrase of Stephen J. Gould, as a series of "punctuated equilibria." For example, the environmentally-induced "collapse" of New Orleans is in the process of taking place in just such a phased manner. The first crisis took place with Hurricane Katrina in August 2005, which destroyed half the city, of which only a fraction was rebuilt. Today, New Orleans has restablized as a smaller, less complex urban environment. However, when the inevitable next major hurricane hits, again a major portion of the city is all but certain to be destroyed, of which again only a portion (if any) will be rebuilt. And this cycle may repeat itself several times before the city is eventually abandoned altogether. Each of these hurricanes forms a "punctuation mark" that marks a phase shift to a new (lower) level of organizational complexity and size, which itself will remains largely stable until the next punctuating event. And of course, in the meanwhile, life continues more or less normally in the rest of the United States, albeit with significant impact on surrounding communities that are absorbing climate refugees from Louisiana.
The second way in which the specter of radical and total collapse is misleading is that it usually assumes that the impact will take place uniformly, that is, that civilizational collapse will affect everyone equally everywhere. Nothing could be further from the truth. William Gibson is often quoted as saying, "The future is already here, it’s just unevenly distributed" and he's absolutely right. But what's less frequently remarked is that this insight applies not just to the cool gizmos and innovative forms of social organization and other similar romantic objects of futurists, but just as much to the nasty impacts of burgeoning global public bads, including those produced by climate change. Thus the victims of vast cyclones in the Ganges and Irrawaddy deltas, or unending droughts in Yemen and Darfur, or cataclysmic brushfires in Australia are all "living the future" just as surely as the whiz kids of Silicon Valley or Bangalore.