Scoping the problem

The Intergovernmental Panel on Climate Change (IPCC, 2001) offered perhaps the most efficient presentation of the climate change problem with its “burning ember” diagram; it is replicated here as Figure 6.1.

The diagram identifies five “Lines of Evidence” with color-coded indicators of economic, social, and natural vulnerabilities. Two are essentially economic indicators of aggregate impacts at the global and regional levels. They are dominated by estimates of the economic damage of climate impacts in market-based sectors such as real estate, agricultural, and energy, and they increase with the global mean temperature. They include, to some degree, evaluations of how various nations and even communities within nations might adapt to climate-related stress driven by higher temperatures as well as the cost of undertaking those adaptations.

In its recently released Fourth Assessment Report (IPCC, 2007), the IPCC concluded that new knowledge supports moving the thresholds of color change indicating increasing risk in the embers to the left – toward lower temperature ranges. It follows that potentially significant impacts are looming in the nearer term. Table 6.1 replicates table 6.1 in Stern, et al. (2006). Based on background work reported in Warren, et al. (2006), it adds texture and content to the moving embers, and it provides evidence that the new IPCC conclusion is an appropriate interpretation of how the science is evolving. Notice, in particular, how Table 6.1 shows clearly that climate impacts are likely to be felt unevenly across the globe.