Addressing future agricultural challenges requires breeding cultivars with improved tolerance to evolving climatic conditions. Many African traditional and indigenous ‘opportunity crops’ have shown increased resilience to climate hazards, yet have received minimal developmental investment. Here the SIMPLE process-based crop model is used to assess the impact of future climate change on the productivity of 5 staple crops and 19 African opportunity crops under low- and high-emissions scenario projections. Roots and tubers show the highest resiliency, while vegetables are the most vulnerable. Cassava, teff, grass pea, sesame seed and finger millet are projected to have the largest productivity increases, while mung bean, lablab, amaranth, Bambara groundnut and maize productivity are projected to decrease substantially. Soybean and cowpea, important cash crops in Africa, are projected to have comparable losses. Crops grown in the Sahel appear most susceptible to climate change, while crops in East and Central Africa show greater resilience. These findings guide regional investments in opportunity crop development and support their inclusion in adaptation measures. African opportunity crops show varied climate resilience, with several projected to outperform staples. Roots and tubers are especially resilient, while legumes and vegetables face declines, particularly in the Sahel.

Global dependence on a few well-researched staple crops exacerbates systemic vulnerabilities to climate change and does not encourage bio- or dietary diversity. The Vision for Adapted Crops and Soils aims to strengthen African food systems by promoting nutritious and climate-resilient “opportunity crops”, also known as "orphan crops", alongside improved land management practices. Here, the Agricultural Model Intercomparison and Improvement Project, together with the Food and Agriculture Organization, Havos.AI, and the African Orphan Crops Consortium, developed a set of 24 indicators for interdisciplinary evaluations of promising opportunity crops in Africa. We employ qualitative and quantitative evidence from climate-crop modeling, agronomy, plant breeding, nutrient composition and social sciences to assess and compare the development potential of 19 opportunity crops and five staple crops. Teff, finger millet, grass pea, pigeon pea, sesame seed, sweet potato, taro, African eggplant and okra are highlighted for their nutrient content and projected yields under climate change.

The Agricultural Model Intercomparison and Improvement Project (AgMIP) developed protocol-based methods for Regional Integrated Assessment (RIA) of agricultural systems. These methods have been applied by teams of scientists working with regional and national stakeholders across Sub-Saharan Africa and South Asia. This paper describes the data sets that were used to implement the AgMIP RIA methods for the Nioro region of Senegal. The goal of the RIA is to assess the potential impacts of climate change on the principal agricultural system in the Senegal peanut basin comprised of peanut, millet, maize and other minor crops and livestock, and to assess adaptations of that system to climate change, under current as well as future climate and socio-economic conditions. The data sets include: the Representative Agricultural Pathways (RAPs) developed for Nioro from 2000-2050; climate data used to implement crop yield simulations; the data used to parameterize the Agricultural Production Systems sIMulator (APSIM) and the Decision Support System for Agrotechnology Transfer (DSSAT) crop models, which include historical climate data and future climate scenarios; and the data used to parameterize the Tradeoff Analysis Model for Multi-dimensional Impact Assessment (TOA-MD) economic simulation model. The analysis is structured around four AgMIP “core questions'' of climate impact assessment.

This study aims to provide improved knowledge and evidence on current (1986–2015) climate variation based on six rainfall indices over five West African countries (Senegal, Niger, Burkina Faso, Ivory Coast, and Benin) using the Climate Hazards Group InfraRed Precipitation with Station (CHIRPS) dataset. On average, precipitation has increased over the central Sahel and the western Sahel. This increase is associated with increase in the number of rainy days, longer wet spells and shorter dry spells. Over the Guinea Coast, the slight increase in precipitation is associated with an increase in the intensity of rainfall with a shorter duration of wet spells. However, these mean changes in precipitation are not all statistically significant and uniform within a country. While previous studies are focused on regional and sub-regional scales, this study contributes to deliver a climate information at a country level that is more relevant for decision making and for policy makers, and to document climate-related risks within a country to feed impact studies in key sectors of the development, such as agriculture and water resources.

The “Great Green Wall” of trees (GGW) is an emblematic Pan‐African initiative of re‐greening the Sahel through afforestation and assisted natural regeneration of trees in order to tackle desertification, soil degradation and to mitigate greenhouse gases. This study investigates (i.e., The Sahel Greenbelt) the potential impacts of the GGW and other assisted natural regeneration of trees on the frequency and intensity of extreme climate events over the Sahel and West Africa using the regional climate model (RegCM version 4.3). Our investigation shows that the Sahel greenbelt would increase significantly the number of rainy days (+9%) and the intensity of heavy rain events over the Sahel while extreme dry spells decrease (−4%). Important shifts appear in the modes of variability of all precipitation indices. These probability distribution shapes reveal tremendous intra‐seasonal variability as the new land use land cover (LULC) changes affect the regional climate. Changes in atmospheric circulation including increase of the moisture convergence and evapotranspiration appeared to be the main drivers of heavy rainfall changes. For temperature extremes, the maximum temperature shows significant decrease around the GGW area during summer and an increase in other seasons while the diurnal temperature range increases significantly without an evident change in temperature trends. Intra‐seasonal distributions of temperature extremes show less obvious changes compared to precipitation extremes. This investigation highlights the role of the planned and implemented re‐greening policies (i.e., afforestation by the GGW project and policies of assisted natural regeneration of trees) in affecting the frequency and the amplitude of some climatic extreme events (e.g., heavy rain events, maximum temperatures, etc.). These planned LULC policies need to be accounted for in the diagnostics and future projections of climate extremes over the region.

Differentiating the impacts of climate change between 1.5°C and 2°C requires a regional and sector-specific perspective. Whereas for some regions and sectors the difference in climate variables might be indistinguishable from natural variability, other areas especially in the tropics and subtropics will experience significant shifts. In addition to region-specific changes in climatic conditions, vulnerability and exposure also differ substantially across the world. Even small differences in climate hazards can translate into sizeable impact differences for particularly vulnerable regions or sectors. Here, we review scientific evidence of regional differences in climate hazards at 1.5°C and 2°C and provide an assessment of selected hotspots of climate change, including small islands as well as rural, urban, and coastal areas in sub-Saharan Africa and South Asia, that are particularly affected by the additional 0.5°C global mean temperature increase. We interlink these with a review of the vulnerability and exposure literature related to these hotspots to provide an integrated perspective on the differences in climate impacts between 1.5°C and 2°C.

Estimation of the response of rainfed crops to heat stress and water stress must adequately account for the uncertainty in climatic and non-climatic factors that affect impact assessments. The objective of this research was to narrow the range of values characterizing the limits within which estimates are expected to fall in the diagnostics of agroclimatic risks. Assessments were made by analyzing historical observations and evaluating the influence of heat stress and rainfall variability on crop water demand, biomass and grain yields of short-cycle cultivars of pearl millet and maize. We used a wide range of consistent and practical sets of crop model ensemble analyses (based on crop management practices such as plant density, fertilization levels, early/late sowing dates and soil types) and climate model ensembles from 2 climate change hypothesis (A1b and RCP8.5) over the West African Sudan-Sahel. Recent rainfall developments show that hazardous intra-seasonal rainfall distribution affects crop productivity, with increased frequency and intensity of daily rainfall, false start and early cessation of the rainy season and decreasing diurnal temperature range. In 2011-2050 perspectives, relative to the 1981-2010 baseline, a slight in crease in temperature (i.e. + 0.6 to + 0.8 degrees C) combined with a stationary to moderate decrease in precipitation leads to a 10 to 15% (8 to 15%) decrease in aboveground biomass production (grain yield). When the warming is moderate (i.e. + 1.4 to 1.8 degrees C), the decline in grain yield worsens (10 to 20%), despite a slight increase in rainfall projections. At these rates of loss in crop production, resilience can be reinforced. However, it will require that climate-smart crop management practices be embedded in sub-seasonal and interannual monitoring and early warning systems.

Climate variability and change affect most socioeconomic sectors in West Africa. It is now admitted that the variability of climate has increased since the 1950s mainly because of the increased concentration of anthropogenic greenhouse gases in the atmosphere. In this study, we analyze the evolution of some extreme temperature and precipitation indices over a large area of West Africa spanning from latitudes 10–25°N and longitudes 17°W–15°E. The results show a general warming trend throughout the region during the period from 1960 to 2010, namely through a negative trend in the number of cool nights, and more frequent warm days and warm spells. This was the case not only for locations inside the continent, but also for those in coastal areas. Trends in rainfall related indices are not as uniform as the ones in temperatures. Nevertheless, a general tendency of decreased annual total rainfall and maximum number of consecutive wet days characterizes the study period. The cumulated rainfall of extremely wet days shows a positive trend in most locations. As for the maximum number of consecutive wet days, it shows an overall decreasing trend from 1960 to the mid 1980s, but starting from the late 1980s, an increasing trend is observed in several locations, indicating that extreme rainfall events have become more frequent in the West African Sahel during the last decade, compared to the 1961–1990 period. Policy implications of these observed trends may include investment and promotion of low cost and environmentally friendly energy production systems, the redesign of infrastructure and production systems to account for higher risks of losses due to floods and/or droughts, and the promotion of research for more heat tolerant crop/animal species and cultivars/breeds.