Exploring net-zero emissions pathways for Africa across different timelines: an integrated assessment modeling

Understanding how net-zero emissions timelines affect sustainable development is essential for climate planning in Africa. We apply the Global Change Analysis Model to explore the continent’s energy–land–water systems under four scenarios: a business-as-usual (BAU) and three net-zero scenarios targeting 2050 (NZ50), 2070 (NZ70), and 2100 (NZ100). Our analysis quantifies how the pace of decarbonization influences Africa’s interconnected energy, land, and water systems. Without new climate policy (BAU), Africa’s net CO _2 emissions could increase by nearly six-fold; from 1.8 GtCO _2 yr ^−1 in 2020 to 10.4 GtCO _2 yr ^−1 by 2100. All net-zero scenarios constrain this growth, with NZ50, NZ70, and NZ100 achieving net-zero emissions by their respective target years through deployment of multiple carbon dioxide removal approaches (e.g. BECCS). Across all scenarios, primary energy supply expands, but its composition shifts under net-zero conditions. Over 2020–2100, renewables account for an average of 49%–53% of primary energy in the net-zero cases, displacing fossil fuels. Net-zero pathways also drive land-use shifts, reducing cropland area by 29%–31% and lowering water demand for food crops by 14%–15%, while increasing water use for BECCS (∼0.9 km ^3 yr ^−1 in NZ50). These land constraints raise staple food prices, averaging $1.16 kg ^−1 in NZ50—about 96% above BAU—with the steepest increase in Western Africa. In terms of mitigation cost, NZ50 is the most expensive pathway ($78 tCO _2 ^−1 ), compared to $68 tCO _2 ^−1 in NZ100. While earlier action enables deeper emissions cuts and faster clean energy transitions, it also imposes higher economic and resource trade-offs. Delayed net-zero deadlines reduce near-term disruption but result in higher cumulative emissions. Given Africa’s development context, we argue that net-zero timelines must balance technical feasibility with economic realities and social justice.