terça-feira, abril 14, 2009

Save the Holocene!

The Anthropocene is a proposed new geological era, meant to signal the idea that we've changed the Earth's biosphere and climate so dramatically that we've left the Holocene, the interglacial period that began 12,000 years ago. It's a catchy (if grim) concept, but one whose utility I find myself seriously questioning. I don't doubt the magnitude of human impact on the planet. Quite the opposite. I think we consistently underestimate the degree of disruption we've already caused by altering the raw biological function of nearly every corner of the Earth and changing the chemistry of its atmosphere, oceans and soils. Very little "wild" anything remains, and all that does remain exists at our sufferance and will endure only with our conscious commitment. None of this, it seems to me, is really a matter of much debate. It's just how the world is now. I get the utility of using the idea of the Anthropocene to provoke recognition of the mind-bending reality that we are transforming the very planet on which we walk. Where the Anthropocene as a concept breaks down, it seems to me, is in the implications it raises, particularly among certain crowds who seem to be saying with increasing frequency, "well, dude, we're in the Anthropocene, anything goes." The first troubling implication is that we can sketch the blueprint of an era better than the Holocene -- the era that produced the planet on which agriculture, civilization and cities arose -- and that we can geoengineer the climate at will to fit that (or any other) blueprint. Because we're really not up for the job. The reality is that modern humanity and human civilization are the fruit of a very tightly banded set of interconnected climate and biological conditions. We need a certain kind of world in order to thrive, and that world is essentially the mild, moderately wet, biologically abundant world of the Holocene. We've never left that world, and in fact we are still intimately dependent on its plenty for our very survival. We don't know of another set of conditions that would allow us to thrive on this planet. There is no human-designed set of planetary conditions that we know of that will suit us better. We don't want the Holocene to end: the whole point is that we want to go back to lower greenhouse gas concentrations in order to continue the Holocene climate indefinitely, as long as we possibly can. The second implication is that we know what we're doing well enough to get the results we want from planetary engineering, even if we don't have a better climate blueprint. We don't. The magnitude of our ignorance about even the most fundamental aspects of the planetary systems on which we depend staggers the informed mind. We're just coming to understand the climate system. We've discovered only a tiny fraction of the planet's species. We are almost still in the age of alchemy when it comes to truly understanding all the interplay of influences that make up an ecosystem. We are simply not up to the task of running the biosphere as a whole like a machine, because we don't have a copy of the operating manual, and we're probably still illiterate anyways. This may be true for generations to come. That doesn't mean that we aren't being forced to make all sorts of choices about how the planet functions. We are, effectively, choosing to screw the climate system up in some unpleasant predictable ways and some potentially disastrous unpredictable ways. Wild nature now pretty much only exists where we protect it and garden it (and this will be more true as climate change shifts habitats). A great many species will only survive if we make saving them a priority (for some, the best we can do may be to find them, freeze them and archive them, but we're not even doing that). What the planet looks like is now largely a matter of our choices. But that doesn't mean that we can choose to do anything. There's a crazy mistaken logic out there that assumes that because we're having to make real choices about the planet's climate and biosphere, we can choose anything we want, redesign the planet in any way we see fit; even that no environmental problems are even problems, because between terraforming and bioengineering, we can figure out how make new planets. I've heard the sneering comments about how environmentalists think natural systems are better because they're natural. But the reality is this: natural systems are better not because they're natural but because they're better at being ecosystems than anything we could possibly come up with in the foreseeable future -- they're more complex than we're able to understand, with creatures and relationships between creatures that have evolved into marvelous particularities of place. These elegant solutions are profoundly more intricate, complex and resilient than anything we know how to make. Preserving those ecosystems, and the species in them, is the best thing we know how to do. Humble and attentive restoration -- through a multitude of interconnected careful efforts crafted to a particular place and alive to the adaptations climate change may demand; each small, but in aggregate massive and planetary -- is the next best. Everything else is a distant, almost wishful, possibility. Our goal, in essence, is to preserve and restore the Holocene biosphere, wherever we can (and in some cases, that might mean looking back to restoring systems and relationships damaged long before the industrial era even began, through re-wilding and resurrection ecology). So, do we need to take responsibility for the planet? Yes. Do we need to take the climate in hand, and aim to release zero or less-than-zero greenhouse gasses? Yes. Do we need to garden nature, greatly reducing our demands on ecosystem services and preserving wild biological hotspots but also practicing adaptive restoration and so on? Yes. But our goal in all of this ought to be clear: preserve the planet on which humanity evolved, and, even more importantly, the planetary era whose attributes underpin everything we now are. Our goal should be, simply, to save the Holocene. Alex SteffenApril 6, 2009 9:07 AM