ISRIC Report 2013/01: Global changes of net primary productivity, affected by climate and abrupt land use changes since 1981

In a previous study (Bai et al., 2012), global changes of remotely sensed greenness (NDVI) and simulated biomass production (TBW) since 1981 have been analysed for the purpose of mapping global soil degradation. The objective of the current research is to refine the findings of this previous research, to more clearly identify areas (grid cells) affected by land degradation. As a start further fine-tuning is needed to improve (non-)linear correlations between various parameters in the analysis. Next, the aggregate impact of climate and the impact of human interventions causing abrupt changes like de- or reforestation should be quantified in a global context. This information can be used to correct the changes in greenness observed via NDVI and better identify areas that were exposed to land degradation and/or improvement. Other factors that cause land degradation and/or
improvement fall outside the scope of this study and the results are therefore first steps in mapping land degradation. New maps will be created by linking the (corrected) changes in greenness to Net Primary Productivity (NPP) and these can be used for further analysis in other projects. The results from this report are used as input for the PBL project ‘Biodiversity, Ecosystem services and Development’ to assess the effects of land degradation on future economic development and biodiversity around the world (using the global model IMAGE). Moreover, results will also be verified in a related project by comparing changes in NDVI, TBW and NPP with local expert judgment from selected countries/areas.