Rapid land-use changes are creating the geology of the Anthropocene

Deforestation, palm oil plantations, and erosion in Kalimantan, Borneo, Indonesia. Image courtesy of the NASA Earth Observatory.

From a historical perspective, land grabbing – deals involving acquisitions of large-scale land assets – is not a new global phenomenon. But it is a resurgent one. Investigative journalists and non-governmental organisations have been reporting on land grabs with particular attention since 2008, when a market-driven spike in food prices triggered a widespread geopolitical crisis over food security. The crisis is ongoing, further complicated by conflicting interests in land for water access, biofuel production, timber, mineral wealth, industrial expansion, environmental conservation, and the protection of local and indigenous peoples’ rights. Academic researchers have begun to examine the social, political, and institutional dynamics of land grabbing, but such expansive land-use transitions can also have profound, lasting effects on physical landscapes. In my article, published in Area, I consider land grabbing as a peculiar force of change in human–environmental systems.

Through agriculture, construction, resource extraction, and other activities, humans move around a lot of dirt. In terms of mass, we displace more of the planet’s surface on an annual basis than any natural agent of geomorphic change, including rivers, glaciers, wind, hillslopes, and waves. Sediment cores from Central America reveal erosion signals coincident with land clearing by Pre-Columbian empires. Lakes across the western US retain the sedimentary record of the catastrophic 1930s Dust Bowl, which followed the introduction of industrial agriculture to the Great Plains. Environmental historians suggest that humans have caused thus far three global-scale pulses of soil erosion in our time on Earth, and the volume of soil and rock we have moved since early millennia BCE has increased nonlinearly as a function of population and technology.

What makes land-use transitions driven by land grabbing so remarkable is their scale: no natural process of environmental change (aside from a cataclysmic event) operates as rapidly over such vast areas and in so many settings. Global landscape changes driven by human activities are the precursors to what will become the geology of the Anthropocene, an epoch characterised by the legacies, material and indirect, of our built environment. Could this new era of land grabbing ultimately register in sedimentary records around the world? Much as past climates have left their own geologic signatures, humans are already leaving our own in the volume of sediment we move – and in the astounding rates at which we move it.

About the author: Dr Eli Lazarus is a Lecturer at School of Ocean Earth Sciences at Cardiff University.

Lazarus E D 2014 Land grabbing as a driver of environmental change, Area, 46: 74–82. doi: 10.1111/area.12072