engleski

Mapping the variability of the potential for carbon fixation under changing agriculture land use at global scale

Expectations are that within the next few decades the food production needs to and will increase in response to demands from a still growing world population. This pressure, engendered through complex socio-economic processes, provokes more intense and sometimes non-adapted use of the resource base causing land degradation which affects the land productivity. Land productivity, whether related to natural, semi natural or agricultural produce, conditions carbon fluxes. Hence it is an important measure in the carbon discussion. Especially when considering effects of land use change and the capacity of soils to be sinks or sources of carbon, information on the dynamics of land productivity related to such land use changes can help to understand the human impact on carbon fluxes. We simplify by assuming that where land productivity increases the potential for net carbon fixation, by plants or in the soil, increases. We consider only agricultural land use change and use the Ramankutty dataset (Ramanakutty and Foley, 1999 and 2012). The potential effect of land degradation through agricultural land use change on the carbon flux is explored here through the relation of agriculture land use change with the observed land productivity dynamics. We calculate land productivity dynamics using time series of remote sensing data modeled into values that are indicative for the seasonal biomass production (Cherlet et al., 2013 ; Ivits et al., 2013). This qualitatively reflects the change in potential for carbon fixation by plants, the input for soil organic carbon and the physical protection that can reduce carbon emissions from soil. Levels of potential for soil organic carbon depletion are modeled empirically using land use and some soil characteristics against a base map of soil organic carbon as produced by Hiederer (Hiederer and Köchy, 2012). This preliminary study is carried out in the framework of the compilation of a new World Atlas of Desertification, an initiative that is coordinated by the Joint Research Centre of the European Commission with support from a wide network of experts.

Carbon fixation; mapping; agriculture land use change; land degradation

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