**Abstract**

Climate has a strong influence on agriculture, which is considered the most dependent human activity on climate variations. The future performance of the Senegalese agricultural sector will depend on its ability to adapt to the negative impacts of climate change. This study demonstrated that the impact of three climate change scenarios (ssp126, ssp245 and ssp585) on the evolution of 14 agroclimatic indicators is already evident in Senegal in the near and distant future. Indeed, the results obtained show a generalized decrease over the whole country in seasonal rainfall totals of about −10% in the near future (2020–2049; PSE horizon) up to −40% in the distant future (2070–2099) for the ssp585 scenario. This decrease in precipitation will be associated with two phenomena, namely a shortening of the rainy season due to increasingly late starts and an increase in dry spells, particularly the DSl and DSxl. The other trend observed is an increase in the frequency and intensity of extreme rainfall events (R99 and R20), which illustrates an increasingly chaotic distribution of rain in the future. Finally, this characterization of agroclimatic indicators made it possible to evaluate and classify the sensitivity of four global models corrected by the CFD-t method in order to run agronomic simulations and to explore adaptation strategies for farmer management in the future.

**Keywords:** agroclimatic indicators, climate change, shared socioeconomic pathways (SSP), near future, far future

### **1. Introduction**

Climate change is now considered one of the major challenges facing the world's populations [1]. Most sectors of human activity on which development efforts are focused are climate-sensitive. The agricultural sector is one of the most vulnerable sectors to climate change [2–6]. Indeed, the Sahelian zone is already subject to high spatiotemporal variability in rainfall. The Sahel experienced continuous drought from the late 1960s to the mid-1990s and early 2000s [7–10]. During these decades of drought, the isohyets lost between 20 and 50% of their annual cumulative

rainfall compared to the 1950s and 1960s. Precipitation has also decreased between 20 and 40%, as well as average temperatures have increased by 1.3°C [11]. This has been described as the most negative trend in precipitation in the contemporary world [12]. The impacts on the populations of sub-Saharan Africa have been very significant with per capita food production falling sharply from 98% in the 1960s to about 86% in the mid-1980s [13, 14]. On average, each inhabitant had lost 12% of the food grown in the 1980s, when drought was at its peak [15]. Climate change will exacerbate these impacts on agriculture. There is growing evidence that changes in climate parameters, namely precipitation, temperature and the intensity and frequency of extreme events, will affect the agricultural sector in several ways [16]. Increased temperatures and the possibility of more extreme thermal events will impact crop productivity. Heading is one of the most sensitive phenological stages to temperature extremes for all cereal species, and during this stage of development, temperature extremes will significantly affect crop production [16, 17]. While increased pockets of drought during the rainy season will limit water availability, thereby promoting soil and groundwater salinization ultimately reducing crop area [18, 19]. Studies have also shown a proliferation of parasites harmful to plants and an increasing incidence of pest attacks which could be detrimental to agricultural production [20]. Given this context of high exposure to the impacts of climate change, the implementation of adaptation measures is an imperative issue for the agricultural sector now and in the future. Thus, several agro-climatic indicators have been created so that agricultural actors can better understand the effects of climate change on their production systems and prepare the necessary adaptations. However, most of the studies that evaluate these agro-climatic indicators focus on global or regional scales. The objective of this paper is to quantify the impacts of global warming on 14 selected agroclimatic indicators in Senegal. Among these indicators, we have the start of the rainy season, different categories of dry sequences and the frequency and intensity of extreme rainfall events. The study was carried out through a spatiotemporal assessment of changes in these agro-climatic indicators in the near (2020–2049) and distant (2070–2099) future in relation to the historical period (1985–2014) for the Shared Socioeconomic Pathways scenarios (ssp126, ssp245 and ssp585).
