van Ittersum, Martin
- Institutionen för växtproduktionsekologi, Sveriges lantbruksuniversitet
- Wageningen University and Research
Sammanfattning
Sub-Saharan Africa (SSA) has the world's largest projected increase in demand for food. Increased dependence on imports makes SSA vulnerable to geopolitical and economic risks, while further expansion of agricultural land is environmentally harmful. Cereals, in particular, maize, millet, rice, sorghum, and wheat, take nearly 50% of the cropland and 43% of the calories and proteins consumed in the region. Demand is projected to double until 2050. Here, we assess recent developments in cereal self-sufficiency and provide outlooks until 2050 under different intensification, area expansion, and climate change scenarios. We use detailed data for ten countries. Cereal self-sufficiency increased between 2010 and 2020 from 84 to 92% despite the 29% population increase. The production increase was achieved by increased yields per hectare (44%), area expansion (34%), and a shift from millet to the higher yielding maize (22%). Outlooks for 2050 are less pessimistic than earlier assessments because of the larger 2020 baseline area, higher shares of maize and somewhat less steep projected population increase. Yet, to halt further area expansion, a drastic trend change in annual yield increase from the present 20 to 58 kg ha-1 y-1 is needed to achieve cereal self-sufficiency. While such yield increases have been achieved elsewhere and are feasible given the yield potentials in SSA, they require structural changes and substantial agronomic, socioeconomic, and political investments. We estimate that amounts of added nitrogen need to at least triple to achieve such yield improvements, but it is essential that this comes with improved context-specific agronomy. Significance Some 54% of the world's population increase until 2050 will occur in sub-Saharan Africa (SSA), while the region has the highest incidence of malnutrition. Its food demand is projected to double between 2020 and 2050. Previous assessments of SSA's potential to achieve cereal self-sufficiency were pessimistic. Here, we show self-sufficiency increased between 2010 and 2020, despite a 29% increase in population, due to area expansion, changes in grown cereal crops and yield increases. The larger baseline area in 2020, a larger share of maize and lower projected population increase make achieving cereal self-sufficiency by 2050 more feasible. Yet, large yield gains are needed to avoid further import dependency and cropland expansion which is detrimental for biodiversity and greenhouse gas emissions.
Nyckelord
food availability; cereal demand; climate change; yield potential; crop area
Publicerad i
Proceedings of the National Academy of Sciences of the United States of America
2025, volym: 122, nummer: 24, artikelnummer: e2423669122
Utgivare: NATL ACAD SCIENCES
SLU författare
UKÄ forskningsämne
Jordbruksvetenskap
Publikationens identifierare
- DOI: https://doi.org/10.1073/pnas.2423669122
Permanent länk till denna sida (URI)
https://res.slu.se/id/publ/142959