Global Land Use History: A New Synthesis

Human use of land has transformed the terrestrial biosphere, causing global changes in ecosystems, landscapes, biogeochemistry, climate, and biodiversity. This global transformation is commonly described as recent in human-environment history. Interdisciplinary paleo and historical data reconstructions and global land use and land cover modeling challenge this view, indicating that human use of land has been extensive and sustained for millennia, and may represent more of a recovery than an acceleration of land use in this century and beyond. Here we present a new global synthesis of recent scientific work on the emergence, history, and future of land use as a global force transforming the Earth system. Central to this synthesis is early human use of fire to engineer ecosystems and other systemic changes in land use dynamics, which together explain how relatively small human populations may have caused widespread and profound ecological changes early in the Holocene, while the largest human populations in history are associated with forests recovery across large regions. While quantitative global models of Holocene and even contemporary land use are still at early stage of development, improved land use histories and models that incorporate land change processes offer a more spatially detailed and accurate view of our planet's history, with a biosphere and perhaps even climate long ago affected by humans. The implicit view from the Anthropocene that humans have reached a historical moment in which "wild nature" is threatened is thus challenged by a view that humans are ancestral shapers and permanent stewards of Earth's terrestrial surface. Land use intensification processes have long sustained human interactions with the terrestrial biosphere, and they continue to evolve as populations grow and urbanize. While these processes are rapidly shifting from their historic patterns in both scale and type, integrative land use and land cover models that incorporate dynamics in human-environment relations help advance our understanding of both past and future land use changes and their global effects.