The PEWS pastoral surveillance and early warning system has been developed by the NGO Action Contre la Faim in the Sahel region where pastoralism and pastoral mobility are one of the keys to environmental and economic resilience. The approach aims to monitor pastoral resources based on satellite images complemented by field data collection and combines two concepts: early warning and surveillance. Early warning is based on the evaluation of biomass production during the rainy season, allowing the anticipation of the stock of pasture that will be available during the next dry season. Surveillance is done through real-time monitoring of green and dry vegetation by remote sensing and a network of field agents, who provide information on the pastoral situation at the local scale several times a month. The project uses phone apps such as 'Pastonavigator' or mapping systems such as MODIS (Moderate-Resolution Imaging Spectroradiometer).

Project in place since 2007 Links to the project reports: https://sigsahel.info/wp-content/uploads/Flyers/ACF_PEWS_Pastoral_Surveillance_Early_Warning_System_Sahel.pdf https://pubdocs.worldbank.org/en/155541591367786058/02-2019-12-06-ACF-Scale-up-of-the-Pastoral-Early-Warning-System-in-the-Sahel-FINAL-REPORT-v4.pdf https://www.worldbank.org/en/data/statistical-capacity-building/data-innovation-fund/scaleup-of-the-pastoral-early-warning-system