The Atlas provides a pictorial overview of the application of land health surveillance science in the Sahel at multiple scales from regional to local levels. It illustrates unprecedented advances in earth observation using remote sensing from space, in the field and on the laboratory bench, combined with geographical information systems, and hierarchical statistical methods. The landscapes, climate, vegetation and trends in vegetation and soil health in the Sahel are described. The Atlas gives a detailed account of the historic, current and projected climate systems that principally determine Sahelian vegetation growth. Coarse resolution remote sensing and rainfall data are presented to provide a regional overview of recent time in trends vegetation growth over the West Africa Sahel. More detailed analyses of the indicative trends of vegetation degradation (land degradation hotspots) or improvement (greening-up) are investigated further using moderate resolution satellite data for a number of locations across the region.
The results demonstrate the complexity of spatial and temporal landscape dynamics at local scales and the challenges they present for interpreting trends from broad scale remote sensing data.
The billion poorest people in the world are disproportionately affected by land degradation because they mostly live in rural areas and are directly dependent on forests, croplands and rangelands for their livelihoods. Agriculture and the land resource base form the foundation for economic development of poorer countries, especially in the Sahel. Land degradation leaves populations vulnerable and decreases adaptive capacity to global change, especially climate change. The Rio+20 outcome document The Future We Want called for urgent action “to reverse land degradation and to strive to achieve a land degradation neutral world in the context of sustainable development.” Strategies for improved land management, such as those included in a Green Economy, emphasize the need for incorporating monitoring, valuation and protection of natural resources into economic decision making.
This Atlas illustrates the potential for harnessing new science and technology to provide accurate and cost-effective methods for assessing and monitoring land health at different scales. Better location specific information on land resource status and trends will improve evidence-based targeting of interventions and promote more rigorous impact assessment.
The Atlas shows how advances in remote sensing from satellites in space to spectrometers on the laboratory bench and systematic field survey can be integrated to provide a basis for operationalizing evidence-based land management. Finally, this report provides rich and valuable insights into the climate and vegetation dynamics of the Sahel, putting recent drought and land use changes in the context of longer-term historic changes.