LOCAL AND DISTANT EFFECTS

We begin by noting that climate events can be socially disruptive both where they occur and elsewhere. The local disruptions are familiar: Storms, floods, heat waves, droughts, and the like have their most obvious consequences where they occur. However, as we noted in Chapter 2, climate change can result in events that create shocks to globalized systems that support human life and well-being and that can therefore affect populations far from where the climate events occur. Here we discuss the susceptibilities of several key globalized systems to harm from such shocks.

Global Food Systems

Under normal conditions the globalization of markets, access to humanitarian relief, and public health systems all tend to reduce the susceptibility of countries and their populations to local climate risks. For example, one of the first responses of governments to expected shortfalls in domestic production is to secure food imports (Timmer, 2010). Yet these global institutions have evolved in, and in some sense been calibrated to, a climate regime that may differ in important ways from the climate of the coming decades. For example, a key feature of commodity markets is the maintenance of stocks that buffer the impact of short-term fluctuations in supply or demand. The levels of these stocks are determined by several factors, including storage costs, interest rates, and the perishability of the commodity, but a key factor is the expected volatility of supply (Wright, 2011). If climate change were to increase the chance of relatively large shortfalls in global production, stocks based on historical expectations of supply variability could be insufficient. Similarly, the capacity of countries to provide humanitarian or public health assistance is related to historical experience with the level of aid needed around the world.

Relatively little peer-reviewed literature has focused on how climate changes in the coming decades and the ability or inability of institutions to adapt to these changes will affect the likelihood of global systemic shocks to food systems, such as rapid price increases. There is some basis for expecting that indicators that aggregate over large areas, such as global food production or global incidence of humanitarian disasters, will be more affected by global climate trends than outcomes in any single location simply because the “signal” of climate change relative to natural variability tends to be clearer at larger spatial scales (Intergovernmental Panel on Climate Change, 2007). For example, Figure 1-1 in Chapter 1 shows that the total fraction of land area experiencing extremely warm temperatures (more than three standard deviations above average) has risen sharply in the past three decades, even if some individual regions have not seen dramatic warming.