Spread of the cycles: a feedback perspective on the Anthropocene

Abstract

What propelled the human 'revolutions' that started the Anthropocene? and what could speed humanity out of trouble? Here, we focus on the role of reinforcing feedback cycles, often comprised of diverse, unrelated elements (e.g. fire, grass, humans), in propelling abrupt and/or irreversible, revolutionary changes. We suggest that differential 'spread of the cycles' has been critical to the past human revolutions of fire use, agriculture, rise of complex states and industrialization. For each revolution, we review and map out proposed reinforcing feedback cycles, and describe how new systems built on previous ones, propelling us into the Anthropocene. We argue that to escape a bleak Anthropocene will require abruptly shifting from existing unsustainable 'vicious cycles', to alternative sustainable 'virtuous cycles' that can outspread and outpersist them. This will need to be complemented by a revolutionary cultural shift from maximizing growth to maximizing persistence (sustainability). To achieve that we suggest that non-human elements need to be brought back into the feedback cycles underlying human cultures and associated measures of progress. This article is part of the theme issue 'Evolution and sustainability: gathering the strands for an Anthropocene synthesis'.

Keywords: Anthropocene; cultural evolution; cycles; feedback; revolution; sustainability.

Figure 1.

Reinforcing feedback loops in the human use of fire. Solid lines with ‘+' signs denote direct relationships. ‘R' denotes reinforcing (positive) feedback loops, which are described in the text.

Figure 2.

Reinforcing feedback loops proposed to have propelled the Neolithic agricultural revolution. (a) Feedbacks behind the establishment of agriculture. (b) Feedbacks behind the endogenous growth of agrarian systems. Solid lines with ‘+' signs denote direct relationships, dashed lines with ‘−' signs denote inverse relationships. ‘R' denotes reinforcing (positive) feedback loops, ‘B' balancing (negative) feedback loops. Numbered loops are described in the text.

Figure 3.

Feedback loops proposed to have propelled increasing state complexity at steppe grassland frontiers. Solid lines with ‘+' signs denote direct relationships, dashed lines with ‘−' signs denote inverse relationships. Here individual loops within polities are not enumerated but the core ‘arms race' reinforcing feedback between federated nomadic pastoralists and agrarian state is denoted. (Also note the aggressive interaction between the focal agrarian state and other agrarian states, which happens across different geographical boundaries, and is also subject to reinforcing feedback.)

Figure 4.

Feedback loops proposed to have propelled the Industrial Revolution (inspired in [20]). (a) Adam Smith's theory of economic growth. (b) Energy and mineral resource feedbacks. (c) Innovation feedbacks. Solid lines with ‘+' signs denote direct relationships, dashed lines with ‘−' signs denote inverse relationships. ‘R' denotes reinforcing (positive) feedback loops, ‘B' balancing (negative) feedback loops. Numbered loops are described in the text.

Figure 5.

The switch in feedbacks to a modern growth regime. Solid lines with ‘+' signs denote direct relationships, dashed line with ‘−' sign denotes inverse relationship. ‘R' denotes reinforcing (positive) feedback loops, ‘B' balancing (negative) feedback loops. Numbered loops are described in the text.

Figure 6.

Reinforcing feedbacks in the transition to renewable energy. ‘Efficiency' refers to the (increasing) thermodynamic efficiency of converting energy to useful work (exergy) leading to (increasing) ‘substitution' of exergy for labour. Solid lines with ‘+' signs denote direct relationships, dashed lines with ‘−' signs denote inverse relationships. ‘R' denotes reinforcing (positive) feedback loops, ‘B' balancing (negative) feedback loops. Numbered loops are described in the text.