Used planet: a global history

Abstract

Human use of land has transformed ecosystem pattern and process across most of the terrestrial biosphere, a global change often described as historically recent and potentially catastrophic for both humanity and the biosphere. Interdisciplinary paleoecological, archaeological, and historical studies challenge this view, indicating that land use has been extensive and sustained for millennia in some regions and that recent trends may represent as much a recovery as an acceleration. Here we synthesize recent scientific evidence and theory on the emergence, history, and future of land use as a process transforming the Earth System and use this to explain why relatively small human populations likely caused widespread and profound ecological changes more than 3,000 y ago, whereas the largest and wealthiest human populations in history are using less arable land per person every decade. Contrasting two spatially explicit global reconstructions of land-use history shows that reconstructions incorporating adaptive changes in land-use systems over time, including land-use intensification, offer a more spatially detailed and plausible assessment of our planet's history, with a biosphere and perhaps even climate long ago affected by humans. Although land-use processes are now shifting rapidly from historical patterns in both type and scale, integrative global land-use models that incorporate dynamic adaptations in human-environment relationships help to advance our understanding of both past and future land-use changes, including their sustainability and potential global effects.

Keywords: Anthropocene; agriculture; environmental history; holocene; niche construction.

Fig. 1.

Time period of first significant land use and recovery from peak land use, 6000 B.C. to A.D. 2000, based on historical reconstructions from the HYDE (A) and KK10 (B) models. Dense settlements from ref. ; black lines delimit regions in Fig. 2. Eckert IV projection.

Fig. 2.

Global areas of significant land use (purple) and total population (red line) within biomes (A and B) and world regions (C and D), 6000 B.C. to A.D. 2000, based on the HYDE (A and C) and KK10 (B and D) historical land-use reconstructions.

Fig. 3.

General model of land-use intensification. Arcs depict individual land-use systems with three phases: intensification (Boserup; 34), involution (Geertz; 43), and crisis (Malthus; 36), with regime shifts from less to more productive land systems. Green line highlights general trend toward increasing productivity with population.