Rainfall and temperature remain the most critical drivers of food crop productivity in Ghana’s forest savannah transition zone; however, increasing variability in their patterns poses significant risks to food security, rural livelihoods, and the sustainability of rainfed food systems. This study investigated rainfall and temperature variability in the Western North Region of Ghana. Methods: Monthly mean rainfall and temperature data (1977–2022), integrated with a GIS-based Inverse Distance Weighting (IDW) interpolation method, were used to assess the spatial and temporal patterns of annual and seasonal rainfall and temperature variability across the region. The study applied both parametric (Ordinary Least Squares regression) and non-parametric (Mann–Kendall and Sen’s slope estimator) methods to identify the direction, magnitude, and statistical significance of rainfall and temperature trends. In addition, 900 crop farmers from 45 farming communities were engaged through structured surveys to capture farmers’ perceptions of climate variability and its perceived impacts on food crop yields, complementing the meteorological analysis. Results: Analysis of long-term data (1977–2022) reveals that annual rainfall (1,441–1,750 mm yr⁻1) and major-season amounts have increased, enhancing soil moisture availability and supporting higher yields of food crops such as maize, cassava, yam, cocoyam, and plantain. However, rising inter-annual variability, declining minor-season rainfall, and unreliable dry-season rainfall have disrupted planting and harvesting schedules, shortened growing periods, and destabilized dual cropping windows, thereby constraining farmers’ capacity to cultivate both major- and minor-season food crops. These shifts collectively reduce food crop yields, heighten production risks, and undermine sustainable food crop production and household food security across the region. Temperature analyses indicate significant long-term warming, with annual maximum temperatures increasing by + 0.0288 °C yr⁻1 and minimum temperatures by + 0.32 °C decade⁻1, the latter exhibiting a more rapid increase during the dry season. Increasing maximum temperatures elevate evapotranspiration and soil moisture loss, heightening heat stress in food crops such as maize, yam, and cocoyam, thereby threatening the sustainability of rainfed food production systems. Concurrently, the rise in minimum temperatures intensifies crop respiration losses and shortens grain-filling durations, threatening both yield stability and the quality of food crops essential for sustainable production. Collectively, the observed warming trends undermine the resilience of rainfed food systems, lowering crop productivity and deepening household food insecurity across vulnerable districts. Farmers’ perceptions of increasing dry spells, delayed rainfall onset, early cessation, and intensifying heat corroborate observed climatic shifts and underscore district-level vulnerabilities. To sustain food production under these conditions, integrated climate-smart interventions are critical. These include the adoption of heat- and drought-resilient crop varieties (Obatanpa maize, NERICA rice, Afisiafi cassava), promotion of climate-smart agronomic practices (mulching, organic soil amendments, and conservation farming), implementation of agroforestry and cover-crop systems, and deployment of precision water management technologies such as solar-powered drip irrigation, automated weather stations, and soil moisture sensors. Additionally, the use of AI- and satellite-driven digital advisory platforms, the establishment of district and regional seed and planting material units, and deliberate investment in farmer-led organizations and farmer field schools will strengthen adaptive capacity, enhance knowledge exchange, and build resilience toward sustainable rainfed food systems in the region. Conclusion: The study revealed increasing warming and changing rainfall patterns, characterized by rising annual and major-season rainfall, declining minor-season amounts, deferred onset and early cessation of rainfall, and rising temperatures. These climatic shifts threaten the sustainability of rainfed food crop systems and food security by shortening growing periods, inducing heat stress, increasing evapotranspiration losses, and lowering crop productivity. Farmers’ perceptions corroborated these observed changes, underscoring district- and regional-level vulnerability to climate variability. Sustaining food crop production under climate variability requires robust food system policies that promote climate-resilient food crop breeding, enhanced soil moisture retention, digital and precision-based water-smart innovations, integrated pest and nutrient management, strengthened farmer learning platforms, and ecologically based rainfed farming systems to build adaptive capacity and ensure long-term food system resilience.

Rainfall and temperature variability in Western North Ghana: Implications for sustainable food crop production

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发表日期：

2026年3月12日

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Bismark Mensah-Brako,
Evans Kwame Buami,
Jefferson-Aaron Ayerbi Totimeh

摘要

Rainfall and temperature remain the most critical drivers of food crop productivity in Ghana’s forest savannah transition zone; however, increasing variability in their patterns poses significant risks to food security, rural livelihoods, and the sustainability of rainfed food systems. This study investigated rainfall and temperature variability in the Western North Region of Ghana. Methods: Monthly mean rainfall and temperature data (1977–2022), integrated with a GIS-based Inverse Distance Weighting (IDW) interpolation method, were used to assess the spatial and temporal patterns of annual and seasonal rainfall and temperature variability across the region. The study applied both parametric (Ordinary Least Squares regression) and non-parametric (Mann–Kendall and Sen’s slope estimator) methods to identify the direction, magnitude, and statistical significance of rainfall and temperature trends. In addition, 900 crop farmers from 45 farming communities were engaged through structured surveys to capture farmers’ perceptions of climate variability and its perceived impacts on food crop yields, complementing the meteorological analysis. Results: Analysis of long-term data (1977–2022) reveals that annual rainfall (1,441–1,750 mm yr⁻¹) and major-season amounts have increased, enhancing soil moisture availability and supporting higher yields of food crops such as maize, cassava, yam, cocoyam, and plantain. However, rising inter-annual variability, declining minor-season rainfall, and unreliable dry-season rainfall have disrupted planting and harvesting schedules, shortened growing periods, and destabilized dual cropping windows, thereby constraining farmers’ capacity to cultivate both major- and minor-season food crops. These shifts collectively reduce food crop yields, heighten production risks, and undermine sustainable food crop production and household food security across the region. Temperature analyses indicate significant long-term warming, with annual maximum temperatures increasing by + 0.0288 °C yr⁻¹ and minimum temperatures by + 0.32 °C decade⁻¹, the latter exhibiting a more rapid increase during the dry season. Increasing maximum temperatures elevate evapotranspiration and soil moisture loss, heightening heat stress in food crops such as maize, yam, and cocoyam, thereby threatening the sustainability of rainfed food production systems. Concurrently, the rise in minimum temperatures intensifies crop respiration losses and shortens grain-filling durations, threatening both yield stability and the quality of food crops essential for sustainable production. Collectively, the observed warming trends undermine the resilience of rainfed food systems, lowering crop productivity and deepening household food insecurity across vulnerable districts. Farmers’ perceptions of increasing dry spells, delayed rainfall onset, early cessation, and intensifying heat corroborate observed climatic shifts and underscore district-level vulnerabilities. To sustain food production under these conditions, integrated climate-smart interventions are critical. These include the adoption of heat- and drought-resilient crop varieties (Obatanpa maize, NERICA rice, Afisiafi cassava), promotion of climate-smart agronomic practices (mulching, organic soil amendments, and conservation farming), implementation of agroforestry and cover-crop systems, and deployment of precision water management technologies such as solar-powered drip irrigation, automated weather stations, and soil moisture sensors. Additionally, the use of AI- and satellite-driven digital advisory platforms, the establishment of district and regional seed and planting material units, and deliberate investment in farmer-led organizations and farmer field schools will strengthen adaptive capacity, enhance knowledge exchange, and build resilience toward sustainable rainfed food systems in the region. Conclusion: The study revealed increasing warming and changing rainfall patterns, characterized by rising annual and major-season rainfall, declining minor-season amounts, deferred onset and early cessation of rainfall, and rising temperatures. These climatic shifts threaten the sustainability of rainfed food crop systems and food security by shortening growing periods, inducing heat stress, increasing evapotranspiration losses, and lowering crop productivity. Farmers’ perceptions corroborated these observed changes, underscoring district- and regional-level vulnerability to climate variability. Sustaining food crop production under climate variability requires robust food system policies that promote climate-resilient food crop breeding, enhanced soil moisture retention, digital and precision-based water-smart innovations, integrated pest and nutrient management, strengthened farmer learning platforms, and ecologically based rainfed farming systems to build adaptive capacity and ensure long-term food system resilience.