Siege warfare followed most of the practice established before, but a larger use of guns, the improvement of gunpowder and sometimes orders to fight to the last stand led to an escalation in violence. This was enhanced too by the growing involvement of civilians, especially in Spain, which gave a more exacerbated dimension to the fights

Chapter 4 synthesizes the concerns of the first three chapters. It is about four topics that underlie the Anthropocene: gradients (the way qualities vary in their intensity over space and time, and the ways such variations relate to causal processes); grading (the ways agents assess and alter such intensities and experience and intervene in causal processes); degradation (the ways highly valuable variations in qualitative intensities are lowered or lost); and grace (the way agents work to maintain gradients, care for those whose lives have been degraded, and value those agents who work and care in such ways). It reframes a few universal thermodynamic variables as (soon to be, if not already) global sociocultural values: energy, entropy, work, and temperature. In addition, it details some of the key features of one important nineteenth-century cosmology in regard to the origins of the Anthropocene (and the discipline of anthropology).

The understanding of heat and temperature was central to the industrial revolution, which needed heat engines to supply power for industrial processes where it was required. The second law was derived from Carnot's insights into the operation of perfect heat engines. The first law was more controversial until the problems were resolved by Clausius and William Thomson through a careful analysis of the first and second laws of thermodynamics. In turn, this led to the understanding of the direction of heat flow through the introduction of a new function of state, the concept of entropy.