“The effort to put climate change in the foreground of Roman history is motivated both by troves of new data and a heightened sensitivity to the importance of the physical environment. The empire-builders benefitted from impeccable timing: the characteristic warm, wet and stable weather was conducive to economic productivity in an agrarian society. The benefits of economic growth supported the political and social bargains by which the Roman empire controlled its vast territory. The favourable climate, in ways subtle and profound, was baked into the empire’s innermost structure. The end of this lucky climate regime did not immediately, or in any simple deterministic sense, spell the doom of Rome.”