IN THE NECK OF THE HOURGLASS

Seen from the long perspective used by Jared Diamond in “Guns, Germs and Steel”, the history of humanity over the last 10,000 years is little more than a footnote to the Neolithic Revolution and the invention of farming that made civilization possible. Unfortunately, this supremely important invention may not be sustainable in the form that it has taken. More obviously than any other part of the human enterprise, agriculture is strategically situated to consume the biosphere from within. In support of the growth-habit industrialized societies have been wedded to for the last 200 years, and the need to provide ever more food for the only “big fierce animal” still increasing in numbers, we have commandeered about 35% of planetary soils for agriculture. The resulting “anthrobleme” of crop and rangeland now covers virtually all of the best soils for our purpose (particularly the loessial soils of the grassland, and large parts of the temperate forest biomes). As a consequence, farmland has expanded into ever more vulnerable soils.

In manipulating soil we intervene in the biosphere at a critical point of constriction. Conceptually, soil sits in the neck of an hourglass-like structure, through which energy and materials flow in passing from one compartment of the terrestrial ecosystem to another. Agriculture inevitably disrupts the soil and damages this crucial link within ecosystems. For this reason, our activities implicate us in what some believe to be the sixth great extinction in the earth’s history. The problem is that farming accentuates many of the natural processes to which soil is subject. In particular, it provokes changes in the erosional cycle, and in the geochemical cycles of major plant nutrients, that have commonly reached pathological states at local or even regional scales within the biosphere, ever since the beginnings of agriculture. Now, the impact of agriculture is not simply confined to the land surface, but has spread to marine systems, where eutrophication associated particularly with the flushing of nutrients into near shore habitats, is producing “dead zones” off North America, Western Europe and Japan.

So what happens now, business as usual, or a soft landing into a post oil and gas future? Human history suggests the former.