Humans as predators of the biosphere: Consumer-resource techno-dynamics and its implications for sustainability

Modern human societies and their socioeconomies impose immense consumption demands on the biosphere, departing from common ecological rules. This detachment makes it urgent to understand the implications of human population growth and consumption dynamics for sustainable trajectories. Models coupling human growth, technology and the biosphere either omit the biosphere as a dynamical variable, restrict technological effects to a single component of the coupled system, or become too complex for analytic stability analysis. Missing is a simple framework in which technology independently modulates population support and per capita biosphere consumption while retaining analytic tractability and allowing confrontation with long-run global data. We address this gap with an ecological consumer–resource model of the human–biosphere system. We separate technological effects into parameters for population support per unit organic carbon and for per capita consumption. Their combination defines a single compound technological impact. We then compare three functional relations: predator–prey, population-driven and supply–demand. For each, we derive the parameter space of stable coexistence. Finally, we calibrate the model to more than 150 years of reconstructed global data to identify technological regimes and locate the present-day system within the stability landscape. Two of the three relations admit Hopf bifurcations and regions without coexistence, while only supply–demand consumption opens a basin toward finite-time biosphere depletion. An extended model combining the three relations provides the best fit to the data and reveals a shift from predator–prey toward supply–demand consumption in recent decades. The supply–demand mechanism dominates the most recent segment in 82% of bootstrap replicates. This attribution remains unchanged under ± 20 % perturbations of the fixed parameters. With the recent regime held fixed, the present-day state follows a biosphere-depleting trajectory in 88% of bootstrap replicates. The immediate threat is therefore not Hopf instability under predator–prey dynamics, but a supply–demand regime in which finite-time biosphere depletion becomes dynamically accessible. The model warns that demographic transition alone is not enough for sustainable trajectories. Consumption efficiency and the form of consumption dynamics are also important for reducing the compound technological impact and shifting the system toward sustainable dynamics.