Evaluation des cultures au Sahel selon leur vulnérabilité aux changements climatiques

The cycles of development of agricultural crops are calibrated to seasonal changes in temperature and precipitation, two elements that can be affected by climate change. In the Sahel region, an increase in temperature is expected in the future, as well as modifications in the quantities and rhythms of precipitation, particularly the start and length of the rainy season, the frequencies of long dry sequences, extreme rainfall, and flooding. The approach to evaluating the vulnerability of crops to climate change involves a phenological evaluation. This approach focuses on the intra-seasonal effects of climate change and aims to analyze the most directly related climatic characteristics to the main challenges of crop management faced by farmers. The evaluation is composed of several steps, including the definition of the analysis zone, the selection of meteorological stations, the development of a phenotypic profile for each crop, and the evaluation of vulnerability. The analysis zone includes the countries of Senegal, Mali, Burkina Faso, and Niger, as well as the southern parts of Mauritania, western Chad, and northern Cameroon, which belong to the Sahel and Sudano-Sahelian regions. The selection of meteorological stations involves collecting data from all stations in the analysis zone and subjecting it to quality control. With a sufficiently complete dataset, it may be possible to subdivide the zone into sub-zones north-south or east-west, as the region is not an agro-ecological zone that is uniform and unique, and the types of crops planted differ according to their location. The development of a phenotypic profile for each crop includes the ideal, tolerance, and threshold temperatures (minimum and maximum) for reproduction and growth, as well as the ideal and threshold precipitation levels and the levels of tolerance to extreme conditions of drought, heat, and flooding. These profiles also reflect the differences in conditions and thresholds during the different phases of the crop development cycle. The evaluation of vulnerability involves querying the database composed of meteorological data, crop profiles, and their individual development phases to identify events that can affect crops. The frequencies of these events over a given period and the existence (or not) of trends in these frequencies can be established at different geographic scales (countries, regions) as well as the probabilities of changes in these frequencies in the future.