Closely interconnected with the distribution of atmospheric water, the last major environmental factor to be considered in this chapter is sunlight (temperature) and its effect on the development of agriculturally ideal landscapes. A paleoclimatic model for average annual temperature is compared with the ancient settlement data in Figure 8.¹ With regard to the question underlying the current examination, a logical conclusion to draw from this map is that there does not appear to be an obvious connection between temperature and agricultural landscapes. Although reasonable, this conclusion may speak more to the lack of information included in a measurement such as “average annual temperature.” Figure 9 offers a more nuanced model compared with the ancient settlement dataset: average monthly range of temperatures.²
 

The trend of temperature data and settlements in Figure 9 seems to be more stable than in Figure 8. This relationship appears to suggest that, whether the overall annual temperature is high or low, agricultural landscapes fall within zone with some range between maximum and minimum temperatures: if the climate is either too cold or too hot, too consistently, large-scale agriculture may not be viable.

It seems that a range of warmer (yet variable) temperatures combined with atmospheric and ground-based sources of water and particular types of soils combine to make an agriculturally ideal landscape. Examining each variable, in turn, the particular specificity of this combination of environmental “recipe” emerges, supporting the FAO data regarding the particularly limited use and availability of agriculturally viable land. Scott points out that, despite the appearance of stability among historical states, the ecological fragility of agricultural landscapes has meant limits to actual state power.³ He writes, “it is essential to acknowledge the fundamental structural vulnerability of the grain complex on which all early states rested. Sedentism arose in very special and circumscribed niches…State-making sites were above all structurally vulnerable to subsistence failures that had little to do with how adept or incompetent their rulers were.”⁴ The idea that agriculturally-based food supplies are particularly vulnerable to the overwhelming influence of environmental conditions makes Scott’s comments especially poignant in light of modern climate change. Considering the particular combination of variables necessary to produce these “very special and circumscribed niches” it is not difficult to understand the reality of such vulnerability.