The Great Depletion Goes On

This is chapter 1 of 5 of our series “Why we need the ‘Europeans of the Planet’, published each Friday.

Humanity's demand on the biosphere currently exceeds the Earth's capacity to regenerate many of the resources and ecological services upon which modern civilisation depends. According to the methodology of the Global Footprint Network, humanity is using natural resources and ecological services at a rate equivalent to approximately 1.7–1.8 Earths, implying a condition of persistent ecological overshoot [1]. In practical terms, this means that forests are harvested faster than they regrow, fish stocks are depleted faster than they recover, freshwater is extracted faster than it is replenished in some regions, and greenhouse gases are emitted faster than natural systems can absorb them.

The precise magnitude of this overshoot remains contested. Critics argue that the Ecological Footprint [2] aggregates disparate environmental phenomena into a single indicator and relies on assumptions that may oversimplify the complexity of ecological and economic systems. Some researchers therefore regard the "1.7 Earths" figure less as a precise measurement than as a heuristic intended to communicate the direction and scale of humanity's environmental impact.

Yet the broader conclusion is difficult to dismiss. Independent lines of evidence point to accelerating biodiversity loss, declining ecosystem resilience, widespread soil degradation, freshwater stress, and a rapidly changing climate. Whether one accepts the precise overshoot calculation or not, humanity is exerting an unprecedented pressure on the natural systems upon which its prosperity ultimately depends.

The deeper question concerns causation. Some observers emphasise population growth, arguing that the planet cannot indefinitely support a population expected to approach ten billion people. Others focus on consumption patterns, noting that a child born into a high-income society may consume many times the resources of one born into a low-income society. A third school stresses technological innovation and human adaptability, arguing that resource scarcity has repeatedly stimulated efficiency gains, substitution, and new forms of production. The debate therefore is not whether humanity faces ecological constraints, but how severe those constraints are and which combination of population, consumption, governance, and technology will ultimately determine the outcome.

You were reading Part 1 of 5: ”The Great Depletion — the planetary challenge”. This series will be continued next Friday with Part 2 of 5: “Prosperity Amid Depletion — the paradox”

1.1 Supporting Evidence

The strongest evidence supporting the general thesis comes from several largely independent observations:

Climate Change

Atmospheric greenhouse-gas concentrations continue to rise, while the Earth's capacity to absorb emissions remains limited. Carbon emissions constitute the largest component of the Ecological Footprint methodology.

Biodiversity Loss

Species extinction rates are significantly above long-term background levels, and habitat conversion continues worldwide.

Resource Depletion

Many fisheries, aquifers, soils, and forests are under sustained pressure from human activity. The existence of local and regional resource depletion is not seriously disputed, even by critics of overshoot accounting.

Earth Overshoot Trend

The calculated Earth Overshoot Day has moved from late in the year in the 1970s to July in recent years, indicating a long-term increase in humanity's aggregate demand relative to biocapacity.

1.2 Important Counter-Voices

A balanced essay should acknowledge at least three major schools of criticism.

1. The Methodological Critics

Researchers such as Vaclav Smil [3] and others have argued that complex ecological realities cannot be reduced to a single "Earths required" figure. They accept environmental pressures but question the precision and policy usefulness of Ecological Footprint accounting.

2. The Technological Optimists

Economists in the tradition of Julian Simon [4] argue that human ingenuity is the ultimate resource. They point to historical examples where predictions of resource exhaustion were overcome by innovation, substitution, improved efficiency, and market adaptation.

3. The Demographic Sceptics

A growing number of economists and demographers argue that humanity's most pressing long-term challenge may not be overpopulation but population ageing and demographic decline in many developed societies. They caution against treating population reduction as a universal solution.

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[1] Global Footprint Network. (2025). Earth Overshoot Day 2025. https://overshoot.footprintnetwork.org/

• This is the primary source for the Earth Overshoot Day and Ecological Footprint methodology. It explains how humanity's ecological demand is compared with global biocapacity and presents the calculation underlying the widely cited claim that humanity currently consumes resources equivalent to approximately 1.8 Earths. The source is indispensable for understanding the overshoot concept, although critics question some of its methodological assumptions.

[2] Wackernagel, M., & Rees, W. E. (1996). Our ecological footprint: Reducing human impact on the Earth. New Society Publishers.

• This landmark work introduced the Ecological Footprint concept and provided the intellectual foundation for later overshoot calculations. The authors argue that humanity's ecological demands can be expressed in terms of biologically productive land and sea area, enabling comparison between consumption and ecological carrying capacity.

[3] Smil, V. (2022). How the world really works: The science behind how we got here and where we're going. Viking.

• Smil offers a nuanced critique of simplistic narratives of either imminent collapse or unlimited technological salvation. While acknowledging environmental constraints and resource pressures, he cautions against reducing complex global systems to single indicators. The book is one of the most influential contemporary counterpoints to overshoot rhetoric.

[4] Simon, J. L. (1996). The ultimate resource 2. Princeton University Press.

• Simon presents the classic cornucopian argument that human creativity and technological innovation consistently expand the effective availability of resources. The book remains the foundational statement of technological optimism in debates concerning population growth, resource depletion, and environmental limits.