What Four Decades of Earth Observation Tell Us about Land Degradation in the Sahel

摘要: The assessment of land degradation and the quantification its effects on productivity have been both a scientific political challenge. After four decades Earth Observation (EO) applications, little agreement has gained magnitude direction in Sahel. large number EO datasets methods associated with complex interactions among biophysical social drivers ecosystem changes make it difficult to apply aggregated indices for these non-linear processes. Hence, while many studies stress that Sahel is greening, others indicate no trend or browning. different generations sensors, granularity studies, study period, applied assumptions and/or computational impact trends. Consequently, uncertainties exist regression models between rainfall, biomass various limit ability science adequately assess develop consistent message degradation. We suggest several improvements: (1) harmonize time-series data, (2) promote knowledge networks, (3) improve data-access, (4) fill data gaps, (5) agree scales assumptions, (6) set up denser network long-term field-surveys (7) consider local perceptions dynamics. To allow multiple perspectives avoid erroneous interpretations, we underline results should not be interpreted without contextual knowledge.