Archaeologist Brian Fagan, emeritus professor at the University of California at Santa Barbara, next spoke about the effects of past climate changes on ancient societies. In particular, he focused on the vulnerability of prior societies to environmental changes, and the lessons they offer for our own. Like Jared Diamond, he sought to suggest that the failures of prior societies were harbringers of our own current vulnerability.

The beginning of human agriculture completely transformed human society, Fagan noted. This also increased human vulnerability to climate, Fagan suggested, because societies were now tied to the land. Ancient Egypt, for example, split apart at one point because a major drought dried up the Nile, triggering agricultural failure. The most successful regions were those where local leaders managed grain supplies. When Egypt was reunited, future Pharoahs were more active in stockpiling grain. The massive El Nino event of 600 A.D., combined with an earthquake, led to the collapse of ancient Peruvian society when agriculture failed. The lesson from these two examples, Fagan argued, is the need for government investment to prepare for inevitable disasters and downturns, as well as for less hubris about the durability of human society. (If I sound skeptical, it is because I am; I doubt Egyptian history really provides much support for central planning, and there is plenty of evidence against Diamond-esque “Collapse” theories.)

Fagan also spoke of rural life in 14th Century Europe – a life governed by the change of the seasons. Yet beginning in 1315, parts of Europe experience nearly seven years of cold rains. Because most medieval peasants lived from harvest to harvest, the prolonged rains had a calamitous effect. Many people on the planet still live in conditions like those of Medieval Europe. The difference, Fagan suggests, is that their vulnerability has increased. Indeed, Fagan said, modern society remains vulnerable despite modern technology and wealth. “The only solution is long-term investment,” he says.

Fagan’s conclusion is that history tells us human society has evolved from nimble hunter-gatherers to cumbersome elephants that are increasingly vulnerable to environmental change. Without political will and leadership, he said, we will remain “utterly vulnerable” to climate change. The devastation wrought by Hurricane Katrina is an example of this, Fagan said (without noting that natural catastrophes cause far more death and devastation in less-developed, less-advanced, less-wealthy societies – suggesting that actual vulnerability is a function of wealth, technology and institutional arrangements ). Because of societal vulnerabilities and climate change, concluded Fagan, “the future of humankind may well be in trouble.” Perhaps, but I hardly think greater political control of resources is the answer.