Climate Change, Shifting Settlements, and Pressure on Biodiversity in South Africa by Michael Oppenheimer and David Wilcove (Princeton University) and Will Turner (Conservation International)

The objective of this project is to examine an effect of climate change that is second order in a causal sense but potentially first order in its impact: how the response of human populations to climate change impinges on vulnerable ecosystems and species that themselves may or may not come under substantial pressure due to the direct effects of global warming. To date, most studies of the likely impacts of climate change on biodiversity have ignored these second-order effects. Yet the response of humans to climate change could have an even greater impact on biodiversity than changes in the climate variables per se. This is of particular concern in areas where changes in productivity or economic viability of certain types of agriculture are projected to bring under the plow those forest or grassland habitats that are currently uncultivated or otherwise managed in a low-impact manner. In addition to the conversion of habitats and associated extirpation of wildlife, the application of pesticides and herbicides, runoff of nutrients, and changes in ground and surface water flows and availability raise concerns about water quality and ecosystem resilience. There may also be significant shifts in livestock production, with either harmful or beneficial impacts to biodiversity, depending on where the livestock go. South Africa, which, according to AOCCM projections, is in the bull’s eye of climate change, and also encompasses significant biodiversity hotspots, presents a perfect laboratory for testing these ideas.