Eco-overshoot (“EO”)

from William Rees and current issue of RWER

Introducing the human predicament

We are cursed to live in interesting times. The human enterprise is in a precarious state of “ecological overshoot” propelled by excessive economic activity and growing populations. Eco-overshoot (hereafter, “EO”) exists when the human demand for renewable (self-producing) resources exceeds ecosystems’ regenerative capacities and waste discharges from people and their economies exceed ecosystems’ assimilative/recycling capacities. This is the archetypal definition of biophysical unsustainability.  . . . .

EO is a recent phenomenon. Anatomically modern H. sapiens have been around for over 300,000 years (Callaway, 2017) but took nearly the whole of that period to reach a population of just one billion in the early 19^th century. Then in only 200 years, < 1/1500^th as much time, human numbers ballooned by a factor of seven and will top 7.9 billion in 2021 (Figure 1). At the same time, real gross world product increased >100-fold and per capita incomes (consumption) increased by a factor of 13 (25 in rich countries) (Roser, 2013). Of course, Earth didn’t get any larger.

We can extract two important lessons directly from the sudden, exponential expansion of the human enterprise. First, the entire phenomenon was made possible by fossil fuels. Gross world product and fossil energy consumption (along with carbon emissions) have increased in lock-step; a similar relationship holds within individual industrial nations with readily explicable variations (e.g., Chima and Freed, 2005). Obviously other products of the scientific revolution – e.g., improving public health – contributed to the boom, but fossil fuels (FFs) were essential. FFs power the global industrial machine; they were (and remain) the principal means by which humans acquired access to all the food and other material resources needed to expand the human enterprise at virtually full biological potential. In population ecology terms, rapidly evolving technology and abundant cheap energy eliminated many of the “negative feedbacks” (e.g., disease, food and other resource shortages, etc.) that historically held our populations in check. Human numbers and virtually all material flows associated with H. sapiens responded with exponential exuberance in what some authors have termed the “great acceleration” (Steffen, Crutzen and McNeill, 2007).

Figure 1. The super-exponential expansion of the human enterprise enabled by the scientific revolution really took off with the extensive use of fossil fuels in the 19^th century

Source of graph: Our World in Data at https://ourworldindata.org/world-population-growth.

Second, of perhaps 15,000 generations of humans, only the most recent 10 or so have experienced sufficient population/economic growth (and technological change) in their lifetimes to notice. For 99.9% of human evolutionary history, human numbers everywhere fluctuated in the vicinity of local carrying capacities as the latter varied with shifting climate and other ecological variables (including bouts of plague which in the 14^th century wiped out a third to half of the Eurasian population in just a few years). In short, while the present generation and other recent cohorts of H. sapiens take continuous growth to be the norm – most economists get nervous if growth falls much below a “healthy” 2-3%/year which means GDP doubles every 23 to 35 years – the past few decades of explosive growth comprise the single most anomalous period in human history.

Concern for EO per se has yet to penetrate economic and developmental policy circles; few politicians have even heard of it. Nevertheless, EO arguably constitutes a crisis of unprecedented proportions. EO is the meta-problem: issues like climate change; plunging biodiversity; tropical deforestation; acidifying oceans; expanding deserts; soil/landscape degradation; air, water and land pollution; resource scarcity and completion; etc., (even the CoViD-19 pandemic), while serious in themselves, are all are mere symptoms of this greater malaise.  read more