Introduction

The relation between empire and ecology has several dimensions. If an “empire” is defined as an expansive state striving to extend its geographical territory by engulfing other states or non-state societies, an underlying objective is obviously to gain control over the land and labor assets of such territory.

In examining actual processes of imperial expansion, it is thus possible to com­pare different ways in which states have appropriated ecological resources from their hinterlands. Such a comparative framework can deal with qualitative differences such as institutions, ideologies, technologies, or consumption patterns, or it can at­tempt to quantify the flows of embodied (i.e., invested) land and labor measured in hectares and hours of human time. The latter approach is particularly useful if the aim is to understand imperial systems in terms of their material metabolism, as measures of the productivity of land and labor can be converted into measures of energy.¹ However, it should rarely be necessary to calculate the quantitative details of imperial energy flows in order to offer analytical observations on the metabolic organization of empires founded, for instance, on the appropriation of human and animal work, food, and fodder.

In trying to understand societal structures such as empires in terms of natural aspects such as biogeography or energy, we need to address the relation between society and nature. This chapter will argue for an understanding of socio-ecological systems that acknowledges the significance of perspectives from both social and natural science, but that is strongly critical of biogeographical determinism.

¹ Smil 1994; Crosby 2006.

Alf Hornborg, Imperial Metabolism In: The Oxford World History of Empire. Edited by: Peter Fibiger Bang, C.A. Bayly,

Walter Scheidel, Oxford University Press (2021). © Oxford University Press. DOI: 10.1093/oso/9780199772360.003.0013. The risk of introducing tangible, physical parameters such as energy or hectares of agricultural land is that this may inspire some readers to think of such aspects as causally primary in a simplistic sense, as it may give the impression of denying the complexity of cultural specificities and historical contingencies in order to re­veal their ultimate evolutionary “function.”^[1079] The challenge, in other words, is to understand the material dimension of imperialism without reducing sociocultural projects to reflections of material exigencies.

A further challenge, also addressed in this chapter, is to understand different varieties of imperial control and appropriation of material resources as being embedded in cultural ideologies that represent unequal exchange as recip­rocal, or at least fair.^[1080] This approach should help us grasp the ideological role of mainstream modern conceptions of national “economic growth” and “techno­logical progress.” It will simultaneously give us reason to reflect on the conspic­uous absence, in the voluminous literature on the political and economic history of imperialism, of critical scrutiny of the global, social, and ecological impli­cations of these notions, which are taken for granted. In particular, this chapter emphasizes that the ecological implications of imperialism are much more polit­ically and morally charged than the (largely unintentional) diffusion of plants and animals.