Impact of climate change on agricultural production in the Sahel - Part 1. Methodological approach and case study for millet in Niger

In the last 30 years the climate of the West African Sahel has shown various changes, especially in terms of rainfall, of which inter-annual variability is very high. This has significant consequences for the poor-resource farmers, whose incomes depend mainly on rainfed agriculture. The West African Sahel is already known as an area characterized by important interaction between climate variability and key socio-economic sectors such as agriculture and water resources. More than 80% of the 55 million population of West African Sahel is rural, involved in agriculture and stock-farming, the two sectors contributing almost 35% of the countries' GDPs. It is therefore obvious that climate change seriously affects the economies of these countries. Adding to this situation the high rate of population increase (similar to3%), leading to progressive pressure upon ecosystems, and poor sanitary facilities, one comes to the conclusion that Sahelian countries, Niger amongst them, will be highly vulnerable to climate change. This paper investigates the impact of current climate variability and future climate change on millet production for three major millet-producing regions in Niger. Statistical models have been used to predict the effects of climate change on future production on the basis of thirteen available predictors. Based on the analysis of the past 30-years of rainfall and production data, the most significant predictors of the model are (i) sea surface temperature anomalies, (ii) the amount of rainfall in July, August and September, (iii) the number of rainy days and (iv) the wind erosion factor. In 2025, production of millet is estimated to be about 13% lower as a consequence of climate change, translated into a reduction of the total amount of rainfall for July, August and September, combined with an increase in temperature while maintaining other significant predictors at a constant level. Subsequently, various potential strategies to compensate this loss are evaluated, including those to increase water use efficiency and to cultivate varieties that are adapted to such circumstances.