Seite - 298 - in Biodiversity and Health in the Face of Climate Change

298 new biophysical context is a decline in energy-returned-on-energy-invested (EROEI), which is one way to measure surplus energy. EROEI was first studied by Odum (1973); it is a foundation of biophysical economics (Cleveland et  al. 1984) and energy analysis (Cleveland 2005; Hall 2011, 2012; Hall and Klitgaard 2011), and is proving useful in macroeconomic analysis (Fagnart and Germain 2016). The low-hanging fruit metaphor explains EROEI.  Initially, extraction occurs at more attractive locations containing high-quality resources that are easy to extract, pro- cess and deliver. Later, resources are found at inhospitable sites, are of lower ther- modynamic quality and are harder to recover, refine and transport. Harder here ultimately means consuming ever-greater amounts of energy in order to extract energy. This is a logical pattern  – pursue the easiest to get first  – but results in a decline over time in surplus energy (Murphy 2014). Early on, a massive surplus of energy misled us with the false promise of endless physical growth. False because, although it largely went unnoticed, surplus energy was on an unrelenting decline (Hall 2012, 2017; Heinberg and Fridley 2016; Morgan 2016). The minimum EROEI needed to support a techno-industrial society is being explored by Hall and his colleagues (Hall 2011, 2012; Hall et  al. 2009; Guilford et  al. 2011). In their analysis, it matters enormously what social services are deemed necessary. As the features included in the definition increase, so too does the EROEI ratio needed to support that society. Historically, EROEI was calculated at the energy source  – the wellhead  – and included only the energy consumed by the hydrocarbon exploration and production industry. In order to make this concept use- ful for social decision-making, Hall et  al. (2009) developed an analysis that accounts for the many indirect energy costs experienced when providing any particular ser- vice to society. This is the surplus energy needed by citizens, organisations or com- munities pursuing their everyday activities and is reported as the extended-EROEI ratio. This research is still maturing but its general  conclusions are firm. Declining surplus energy at the societal level is bringing ever closer the day when the resources at our disposal will be insufficient to maintain growth in, and perhaps the full main- tenance of, the personal, social and urban systems to which we have become accustomed. Thus, considering just one aspect of one input to techno-industrial society’s metabolism reveals a significant vulnerability. All is well so long as there is a sig- nificant surplus of energy. However, over time that surplus is getting smaller. 13.2.2 Climate Disruption Climate disruption, a consequence of the rapacious use of hydrocarbon-based fuels, is empirically established and settled science; the evidence is unequivocal. Profound changes to the earth’s thermal patterns are occurring (IPCC 2014) and appear to be accelerating (Herring et  al. 2018). Furthermore, what were once worst-case and decades-distant consequences are now taking place (Hansen et  al. 2017). There is hope that the Rio/Kyoto/Copenhagen/Cancun/Durban/Doha/Warsaw/Lima/Paris R. De  Young