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ABSTRACT This paper provides an analysis of the interplays between climate risks, eco-systems and adaptation decisions using South American and Sub- Saharan African farm surveys. Climate risk indicators such as seasonal Coefficient of Variation in Precipitation ( CVP) and Diurnal Temperature Range ( DTR) are matched with major eco-systems. Adoption decisions of the six natural resource enterprises are modelled using a spatial Logit model. First, this paper finds that climate risks are higher in the grasslands and meadow eco-systems in South America as they are high in the lowland arid zones in Africa. However, climate risks across the continent are, compared with Sub-Saharan Africa, much lower in South America. Second, a higher temperature implies a higher climate risk in Africa, which is not the case in South America owing to the predominant influences of regional weather events such as the ENSO. Third, while the CVP is a dominant risk factor in Africa, the DTR is a dominant risk factor in South America due to the vast ranges of the Andes Mountain. Winter DTR is predicted to fall by 3 °C under both the UKMO and the GISS scenarios by the middle of this century. Altered climate risks will push a large number of farmers to switch away from a crops-only enterprise due to a large decrease in daily temperature variability. Farmers adapt by increasing a crops-livestock enterprise in the grasslands with wood cover and subtropical drought-deciduous forests. This paper provides a coupled analysis of global (climate), local (eco-systems) and individual (adaptation) processes. [ABSTRACT FROM AUTHOR]

Aim Species richness depends on climate and land use. Maintaining locations with favourable climate and land-use patterns is critical for protecting biodiversity because the loss of either can reduce the species richness that an area supports. Currently, the Guiana Shield (GS) receives abundant precipitation and has relatively light land use. For species richness this constitutes a good–good combination of climate and land use, respectively. In contrast, much of eastern Brazil receives low levels of precipitation and has heavy land use, which is a bad–bad combination for species richness. Thus, the current distribution of precipitation and land use in northern South America is relatively favourable for biodiversity. Palaeoclimate and model studies suggest, however, that the precipitation patterns for the two regions have switched before and could switch in response to greenhouse gas emissions. This paper examines the potential consequences of reconfiguring climate with respect to existing land-use patterns using South America as an example. Location South America north of 20° S and east of the Andes. Methods Ecosystem structure and function are modelled under (1) historical climate and (2) altered precipitation following a shift in the location of the Inter-Tropical Convergence Zone (ITCZ). The distribution of precipitation, biomes, net primary productivity (NPP) and land use are then used to predict levels of species richness under the two climate scenarios. Results Climate changes could shift the distribution of vegetation and NPP such that conditions favourable for species richness in the GS region disappear. If land-use patterns were not prohibitive in eastern Brazil, the improved climate conditions there could compensate for the GS loss (assuming migratory barriers are overcome). Instead, existing land-use patterns cause the combined species richness projected for the two regions to plummet. Main conclusions Human activities will alter current configurations of land use and climate throughout the world. For species richness, new configurations are likely to include both positive and negative combinations of climate and land use. However, the irreversibility of past extinctions due to land-use patterns loads the dice against species richness. [ABSTRACT FROM AUTHOR]