Dr. Jason Bradford, the biology brains behind Farmland LP (more on that here), ticked off a few of the key vulnerabilities of the U.S. food system in his presentation on sustainable agriculture:

■ Commercial agriculture consumes 10.3 quads (quadrillion BTUs) of primary energy in order to produce 1.4 quads of food energy. The inputs are mainly fossil fuels used in running tractors, producing artificial fertilizers, producing seeds, trucking, refrigeration, processing, freezing and cooking.

■ Commercial agriculture not only depletes non-renewable resources and degrades soil, air, and water, but it also releases 5 billion pounds of harmful chemicals and massive amounts of greenhouse gas emissions into the environment per year.

■ Animal waste provides critically important fertilizer to small distributed farms, but in the modern massive feedlots of concentrated animal populations it becomes an environmental hazard. All the feed transported to the feedlots uses petroleum fuels, and the hay is grown using ancient "fossil water" pumped from deep, essentially non-renewable aquifers.

■ Over the last four decades or so, runoff from commercial agriculture has resulted in massive "dead zones" near our shorelines caused by algae blooms that suck the oxygen out of the water and create anoxic environments where nothing can live. (The dead zone in the Gulf of Mexico has grown to an estimated 8,500 square miles.)

■ Just three crops comprise 71% of U.S. crop acres: corn, soybean, and wheat.

■ Monsanto, Pioneer, and Syngenta —all basically chemical companies — dominate the seed industry with patented GMO seeds. Those seeds are finely tuned to the temperature, rainfall, and so on of the recent past, making climate change a major threat to the whole food regime (more on that here).

■ Likewise, a handful of giant companies now control the vast majority of the food supply system — a stark contrast to the millions of small family farmers who dominated it prior to the 1960s.

■ Nearly all of the food delivery system uses just-in-time inventory methods, so there is only one to three days' supply at any point in the distribution chain.

In short, Bradford explained, we have built a complex food supply system with very low diversity and strong connectivity. Yet in nature, those characteristics lead to instability. Stable systems are highly diverse with weak connectivity. The very complexity and interconnectedness of our food web is, in itself, a dangerous vulnerability.

Bradford aptly compared our blithe faith in the food supply system to "the hubris of Wile E. Coyote" just before he realizes he's about to plunge into the canyon.