“Humans,” the species nobody asked for, “now dominate Earth,” the brutes, “changing it in ways that threaten its ability to sustain us and other species,” for it is our duty to sustain other species. So goes, plus or minus, the opening strains of a melody we have been singing for lo these forty years.
This particular arrangement was conducted by Anthony D. Barnosky and his orchestra in the Nature article “Approaching a state shift in Earth’s biosphere.”
Listen to the soothing lyric! “Localized ecological systems are known to shift abruptly and irreversibly from one state to another when they are forced across critical thresholds.” Notice the sly use of forced: some thing is having its naughty way with Nature. What could that thing be? You know.
Historical examples of tipping points tipped? How’s a mass extinction grab you? Sure, the last one was 65,000,000â€‰years ago, and took “2,000,000â€‰yr to complete”, but it “could have been much shorter” (emphasis mine, and yours!). And then there’s the Cambrian explosion—an explosion!—half a billion years ago, with a bang extending over a mere 30 million years. (Let’s don’t mention the “explosion” was one of biological diversity.) Finally, glacial-interglacial transitions, the last of which was just the other day, about 11,000 years ago, and boy was it a whopper, causing the
extinction of about half of the species of large-bodied mammals, several species of large birds and reptiles, and a few species of small animals; a significant decrease in local and regional biodiversity as geographic ranges shifted individualistically, which also resulted in novel species assemblages; and a global increase in human biomass and spread of humans to all continents.
Now it is a fact that George Bush knew of each of these events, and did nothing to stop them! We’re in luck that our current administration is more caring. Just never mind the positive correlation that the coming of ice and thriving of Man were simultaneous: what matters is the transition killed off picturesque woolly mammoths.
Barnosky’s refrain is “past critical transitions occur very quickly”, meaning if they occurred very quickly in the past, they can do so again in the future. Sure, “quickly” is in thousands to millions of years, but why don’t you stop being critical and realize that “Critical transitions lead to state shifts, which abruptly override trends and produce unanticipated biotic effects.” Unanticipated, meaning we know exactly what will happen and it won’t be good.
And since we don’t know, we need to “improve biological forecasting” to anticipate “critical transitions” that can emerge; this would “minimize biological surprises that would adversely impact humanity.” This works because forecasts are an apt substitute for actual knowledge. Right, Gav?
Let me throw two more terms at you: “synergy and feedbacks.” Ha! These terms make tipping points realer when it dawns on you that individual geologic and biologic are not as absolutely, perfectly independent. Things interact: one thing changes another, which changes the first thing back, and so on synergistically. Sure, “Potential interactions between overlapping complex systems, however, are proving difficult to characterize mathematically, especially when the systems under study are not well known and are heterogeneous.”
By God, we don’t even know how many of these feedbacks and synergisms are out there! But they’re there, bet on it. And don’t you know that because we don’t know, you just know that changes in any of them caused by the likes of you, has to change things for the worse?
This is why we must “guide the biologic future.” After all, if we don’t, who will? We must keep the Earth as she is, in pristine purity, because however she is now (or was, just before the Industrial Revolution), is how she always was and always must be. Forgot those other tipping points: they’re in the past. The Earth of 1890, or 1850, or whatever, is our goal. Those climates are not in the past. They’re our future, as long as we act now.
Otherwise, “the biological resources we take for granted at present may be subject to rapid and unpredictable transformations within a few human generations.” Unpredictable: this is why we must predict them! As our last presidential election taught, change is not always for the better. Indeed, change is always involves “loss”, a word Barnosky loves. Why, if it weren’t for the last glaciation, we wouldn’t even be here to complain about it. Let that sink into your brain pans.
Incidentally, the same issue of Nature finds Paul “The End Is Near And This Time I Mean It” Ehrlich wielding his pen in service to the noble goal of “Securing natural capital and expanding equity to rescale civilization”. We’ll look at this tomorrow.