Akinwale Temitope Ogunrinde

Compound climate extremes pose disproportionate risks to societies and ecosystems, yet their evolution across Africa remains poorly constrained. Here we present the first continent-wide, multi-generation assessment of historical and projected temperature–precipitation compound hot–dry extremes across Africa using CMIP5 and CMIP6 multi-model ensembles under the full range of emission scenarios. Observations indicate continent-wide warming of 0.21 °C decade-1; during 1980–2020, accompanied by spatially heterogeneous precipitation trends, establishing a baseline of increasing compound vulnerability. Despite projected increases in precipitation over much of tropical Africa, both CMIP5 and CMIP6 consistently project strong intensification of compound hot–dry extremes, driven primarily by accelerated warming. By mid-century (2035–2065), compound hot–dry frequency increases across all regions, with southern Africa experiencing 0.33–0.43 hot–dry months yr^-1; in CMIP6. By end-century (2070–2100), frequencies in western and eastern southern Africa reach 0.36–0.62 months yr^-1; under high-emission scenarios, representing more than a doubling relative to low-emission pathways. Compound event severity intensifies nonlinearly: cumulative event magnitude exceeds 10–13 σ in southern Africa and Madagascar, while mean event duration lengthens from ∼1–1.5 months historically to 4–6 months under high emissions. CMIP6 systematically projects stronger increases in compound frequency, magnitude, and duration than CMIP5, reflecting enhanced land–atmosphere coupling and higher climate sensitivity. Although strong mitigation substantially limits these increases, compound hot–dry extremes intensify even under low-emission pathways. These results demonstrate that compound climate risk may escalate regardless of mean precipitation trends, underscoring the urgency of compound-aware adaptation strategies and the substantial mitigation benefits of limiting future climate impacts.

Compound climate extremes pose disproportionate risks to societies and ecosystems, yet their evolution across Africa remains poorly constrained. Here we present the first continent-wide, multi-generation assessment of historical and projected temperature–precipitation compound hot–dry extremes across Africa using CMIP5 and CMIP6 multi-model ensembles under the full range of emission scenarios. Observations indicate continent-wide warming of 0.21 °C decade-1; during 1980–2020, accompanied by spatially heterogeneous precipitation trends, establishing a baseline of increasing compound vulnerability. Despite projected increases in precipitation over much of tropical Africa, both CMIP5 and CMIP6 consistently project strong intensification of compound hot–dry extremes, driven primarily by accelerated warming. By mid-century (2035–2065), compound hot–dry frequency increases across all regions, with southern Africa experiencing 0.33–0.43 hot–dry months yr^-1; in CMIP6. By end-century (2070–2100), frequencies in western and eastern southern Africa reach 0.36–0.62 months yr^-1; under high-emission scenarios, representing more than a doubling relative to low-emission pathways. Compound event severity intensifies nonlinearly: cumulative event magnitude exceeds 10–13 σ in southern Africa and Madagascar, while mean event duration lengthens from ∼1–1.5 months historically to 4–6 months under high emissions. CMIP6 systematically projects stronger increases in compound frequency, magnitude, and duration than CMIP5, reflecting enhanced land–atmosphere coupling and higher climate sensitivity. Although strong mitigation substantially limits these increases, compound hot–dry extremes intensify even under low-emission pathways. These results demonstrate that compound climate risk may escalate regardless of mean precipitation trends, underscoring the urgency of compound-aware adaptation strategies and the substantial mitigation benefits of limiting future climate impacts.

Compound climate extremes pose disproportionate risks to societies and ecosystems, yet their evolution across Africa remains poorly constrained. Here we present the first continent-wide, multi-generation assessment of historical and projected temperature–precipitation compound hot–dry extremes across Africa using CMIP5 and CMIP6 multi-model ensembles under the full range of emission scenarios. Observations indicate continent-wide warming of 0.21 °C decade-1; during 1980–2020, accompanied by spatially heterogeneous precipitation trends, establishing a baseline of increasing compound vulnerability. Despite projected increases in precipitation over much of tropical Africa, both CMIP5 and CMIP6 consistently project strong intensification of compound hot–dry extremes, driven primarily by accelerated warming. By mid-century (2035–2065), compound hot–dry frequency increases across all regions, with southern Africa experiencing 0.33–0.43 hot–dry months yr^-1; in CMIP6. By end-century (2070–2100), frequencies in western and eastern southern Africa reach 0.36–0.62 months yr^-1; under high-emission scenarios, representing more than a doubling relative to low-emission pathways. Compound event severity intensifies nonlinearly: cumulative event magnitude exceeds 10–13 σ in southern Africa and Madagascar, while mean event duration lengthens from ∼1–1.5 months historically to 4–6 months under high emissions. CMIP6 systematically projects stronger increases in compound frequency, magnitude, and duration than CMIP5, reflecting enhanced land–atmosphere coupling and higher climate sensitivity. Although strong mitigation substantially limits these increases, compound hot–dry extremes intensify even under low-emission pathways. These results demonstrate that compound climate risk may escalate regardless of mean precipitation trends, underscoring the urgency of compound-aware adaptation strategies and the substantial mitigation benefits of limiting future climate impacts.

Drought persistence in the Sudan–Sahel transition zone of Northern Nigeria poses a substantial risk to agricultural productivity. This study develops a Hybrid Prophet–Long Short-Term Memory (LSTM) architecture to address the existing research gap in near-term predictive capacity for non-stationary hydroclimatic time series. Utilizing Kano State as a case study, the Prophet algorithm was employed to extract deterministic trends from the Standardized Precipitation Evapotranspiration Index (SPEI-12) derived from CRU TS v4.09 data (1980–2024), while an integrated LSTM network modeled the stochastic residuals. Diagnostic results indicate a statistically significant trend toward moisture recovery (p < 0.0001). Comparative analysis demonstrated that the hybrid model significantly outperformed standalone baselines, achieving a Nash–Sutcliffe Efficiency (NSE) exceeding 0.87 and a 67.2% reduction in Root Mean Square Error (RMSE). Furthermore, the framework accurately simulated hydroclimatic transitions with a directional accuracy exceeding 87%, confirming high predictive reliability. Projections for the 2025–2030 period indicate a continued positive moisture shift of approximately 0.9 SPEI units. These findings underscore the technical necessity of decoupling non-linear noise from deterministic signals to resolve complex drought dynamics. Consequently, the proposed framework serves as a robust tool for near-term climate prediction. Scaling this methodology across diverse agroecological zones is recommended to enhance national drought early warning systems and regional climate resilience strategies.

Drought represents a significant hydroclimatic hazard in arid regions of Asia and Africa, where climate change exacerbates evaporative demand, leading to intensified moisture stress, agricultural disruptions, and water insecurity. This study evaluates the Evaporative Demand Drought Index (EDDI) as a complementary tool to traditional precipitation-based indices, such as the Standardized Precipitation Index (SPI) and Standardized Precipitation-Evapotranspiration Index (SPEI), for monitoring drought dynamics, with a focus on flash droughts and evapotranspiration-driven anomalies. Utilizing high-resolution ERA5-Land reanalysis data (0.1° spatial resolution) from 1983 to 2023, EDDI was computed using the Penman-Monteith formulation across multiple timescales, including sub-weekly (1–3 weeks) and monthly (1–12 months) periods. The analysis encompassed diverse arid zones classified by the Intergovernmental Panel on Climate Change, including the Sahara (SAH), Mediterranean (MED), Arabian Peninsula (ARP), West Central Asia (WCA), Eastern Europe (EEU), West Siberia (WSB), East Siberia (ESB), East Central Asia (ECA), and Tibetan Plateau (TIB). Performance assessment involved modified Mann-Kendall trend tests, Sen’s slope estimation, Spearman rank correlations, run theory for drought characterization (duration, severity, intensity, peak, and frequency), and a case study of the 2010 drought event. Results revealed pronounced spatial and temporal heterogeneities in drought patterns. EDDI exhibited stronger drying trends compared to SPI and SPEI, driven by significant increases in reference evapotranspiration (ETo; 2.0–5.16 mm year⁻¹) and temperature (0.02–0.05°C year⁻¹) across most regions, except the TIB, where wetting trends predominated due to elevational effects. In hyper-arid areas such as SAH and ARP, EDDI identified significant drying in 45–60% of grid cells, in contrast to SPI's wetting signals, underscoring EDDI's sensitivity to atmospheric demand independent of precipitation. Spearman correlations between EDDI and SPEI were notably strong (ρ ranging from -0.83 to -0.91 at 1-month scales), exceeding those with SPI (-0.41 to -0.79), particularly in SAH (-0.91 for EDDI-SPEI). Drought frequency intensified post-2000 in all regions except TIB, with EDDI capturing higher severity in SAH and ARP due to elevated ETo. Run theory analysis showed that, at longer timescales, drought duration, severity, and intensity increased, while frequency decreased; EDDI consistently indicated more acute conditions than SPI in water-limited environments. During the 2010 drought, EDDI detected the onset 2–4 weeks earlier than SPI in ARP and SAH, highlighting its utility for rapid-onset events through sub-monthly sensitivity to ETo anomalies. Spatial progression revealed severe drought (category C4) expanding in SAH and EEU at 6–12-month scales, with EDDI and SPEI aligning more closely than SPI, reflecting the influence of vapor pressure deficits and land-atmosphere feedbacks grounded in the Budyko framework. These findings affirm EDDI's role as an indirect proxy for drought stress via evaporative demand, complementing precipitation-focused indices in arid settings where ETo dominates. Limitations include potential overestimation in irrigated areas and assumptions of stationarity under non-stationary climate conditions. Integration of EDDI into operational early warning systems could enhance proactive management, supporting adaptive strategies like water allocation and resilient agriculture amid projected aridification.