The research, conducted by Lindumusa Myeni and Nisa Ayob of North-West University, analysed daily climate records from ten weather stations spanning contrasting agroecological zones in the Free State, Gauteng, KwaZulu-Natal, Mpumalanga and North West provinces, together with district-level maize yield records spanning more than 30 growing seasons from 1993/94 to 2023/24. The five provinces together produce over 85 percent of South Africa’s maize. The authors computed rainfall- and temperature-based extreme climate indices following the Expert Team on Climate Change Detection and Indices framework, then applied Sen’s slope estimator and the Mann-Kendall test to detect trends, Pearson correlation to link extremes with yields, and stepwise multiple regression to identify the dominant climatic drivers of yield variability.

The headline finding is unambiguous warming. Mean seasonal air temperature increased from 0.02 degrees Celsius per annum at the wetter Lydenburg station to 0.06 degrees Celsius per annum at the semi-arid stations of Klerksdorp and Vryburg, while maximum daytime temperatures rose by 0.05 to 0.11 degrees Celsius per annum across all stations. More striking still, the frequency of very hot days increased by 0.19 to 0.50 percent per annum, with the largest increases recorded at Klerksdorp, Newcastle and Carolina. In mirror image, the frequency of extreme cold days declined by 0.10 to 0.29 percent per annum at most stations. Together these trends signal a clear shift toward hotter growing-season conditions, with peak heat intensifying faster than average temperatures, a pattern the authors argue underscores why extremes, not just means, must be monitored.

Rainfall told a subtler story. Total seasonal rainfall showed highly variable and statistically non-significant trends across all stations, ranging between minus 7.08 and plus 5.91 millimetres per annum, consistent with earlier national analyses that found no coherent long-term rainfall signal. But the texture of rainfall is changing. The number of rain days declined significantly at 40 percent of stations, including Bronkhorstspruit, Estcourt, Klerksdorp and Vereeniging, at rates of 0.55 to 1.16 days per annum, implying that rain is becoming less frequent but potentially more intense, with longer dry intervals between events. Consecutive dry days increased significantly only at Vereeniging, at roughly 19 additional days per decade, while heavy rainfall indices rose significantly only at Lydenburg, where more intense downpours raise risks of runoff, erosion and waterlogging on vulnerable soils.

Perhaps most consequential for crops is the trajectory of moisture balance. The Standardized Precipitation Evapotranspiration Index, or SPEI, which captures the competition between water supply and atmospheric demand, declined significantly at 30 percent of stations, including Estcourt, Klerksdorp and Newcastle, at rates of 0.03 to 0.05 per annum. This indicates that evapotranspiration, driven largely by rising air temperatures, is increasingly outpacing precipitation, deepening water stress and drought severity. For rainfed maize, which dominates production in these semi-arid environments, such trends translate directly into greater susceptibility to prolonged dry conditions, reduced soil moisture and unstable yields. The study also noted a significant decrease in minimum nighttime temperatures at Bloemfontein, raising frost risk in that district, a reminder that warming is not spatially uniform.

Maize yields themselves varied enormously across the study municipalities. Mean yields ranged from as low as 2.42 tonnes per hectare at Vereeniging and Bloemfontein to as high as 7.49 tonnes per hectare at Estcourt, with cooler, wetter districts such as Newcastle, Lydenburg and Carolina generally outperforming drier western areas like Vryburg, Klerksdorp and Bloemfontein. Yield stability differed just as sharply: coefficients of variation spanned from 29.24 percent at Vereeniging to 54.28 percent at Vryburg, with high values at Vryburg, Newcastle and Bloemfontein pointing to strong interannual fluctuations likely driven by erratic rainfall, dry spells and temperature extremes during critical growth stages.

The correlation analysis drew a clear line between specific extremes and yield outcomes. Maize yields correlated negatively with heat indices across all municipalities, with the strongest significant relationships in semi-arid regions: at Vryburg, mean seasonal temperature correlated at r equals minus 0.64 and very hot days at r equals minus 0.62, while at Klerksdorp the corresponding values were minus 0.52 and minus 0.48. At Bethlehem, very hot days correlated at minus 0.46. By contrast, cold-related indices showed weak or non-significant correlations at most stations, suggesting cold stress is far less influential than heat. On the moisture side, yields correlated positively with total rainfall, rain days and SPEI, with SPEI reaching r equals 0.76 at Klerksdorp and 0.68 at Vryburg, confirming moisture availability as the primary limiting factor in these water-scarce districts. Consecutive dry days correlated negatively with yields at Klerksdorp, reinforcing the damage inflicted by intra-seasonal drought.

Stepwise multiple regression then quantified how much of the yield variability climate extremes can actually explain. The explanatory power of the models ranged from weak at Lydenburg, where the coefficient of determination was just 0.12, to strong at Klerksdorp and Vryburg, where it reached 0.69, meaning climate variability accounted for up to 69 percent of interannual yield fluctuations in these water-limited regions. SPEI carried large, highly significant positive coefficients at Klerksdorp and Vryburg, leading the authors to propose the drought index as a practical early-warning indicator for maize production forecasting and risk assessment. At Estcourt and Newcastle, with coefficients of determination of 0.49 and 0.67 respectively, both temperature extremes and rainfall characteristics, including amount, frequency and intensity, shaped yields in more complex ways. Where model explanatory power was low, non-climatic factors such as soils, management and technology likely dominated.

The authors stress that these relationships are scale-dependent and that coarser provincial or national analyses can obscure localised impacts, which is why district-level assessment matters for crafting adaptation. Their recommendations diverge by zone: in hot, semi-arid areas, drought- and heat-tolerant seed varieties, adjusted planting dates, conservation tillage, mulching, residue retention, cover cropping, rainwater harvesting and supplementary irrigation offer the most promise, while in wetter regions the priority is managing rainfall distribution variability, mitigating heat stress and optimising planting calendars. Climate information services, seasonal forecasts and agrometeorological advisories, they argue, can help farmers anticipate risks and act proactively rather than reactively.

The study acknowledges limitations, including the coarse resolution of station data, seasonal indices that may miss extremes during critical phenological windows, and district-level yield records that mask local variation in soils, cultivars and management. Future work, the authors suggest, should integrate high-resolution climate projections, finer-scale yield and management data, and machine learning approaches capable of capturing nonlinear climate-yield relationships. With heat extremes intensifying and moisture availability declining across the maize belt, the message for policymakers is that uniform adaptation policies will fall short; resilience must be built district by district, informed by the specific climatic constraints each farming community faces.

Subject of Research: Long-term trends in extreme climate indices and their impacts on district-level maize yields in South Africa's summer rainfall region

Article Title: Long-term changes in the climate extremes and their impacts on maize yields in the summer rainfall region of South Africa

Article References: Long-term changes in the climate extremes and their impacts on maize yields in the summer rainfall region of South Africa. (n.d.). https://doi.org/10.1007/s00704-026-06550-y

Image Credits: AI Generated

DOI: 10.1007/s00704-026-06550-y

Keywords: climate extremes, maize yields, South Africa, heat stress, drought, SPEI, rainfed agriculture, Mann-Kendall trend analysis, semi-arid regions, food security, adaptation strategies, agroclimatology

Catalina Rico Lenta and Ana Ladio built their study around farmers who sell at the Nahuel Huapi Family Farmers’ Market, a hub of local food production in the Argentinian Andes. Drawing on extensive ethnobiological fieldwork, the researchers organized a participatory workshop in which farmers identified and ranked the Components of Change, or CoC, affecting their productive systems. Rather than treating drought, market pressures, or invasive species as isolated problems, participants described them as interconnected strands of a single web, each capable of triggering consequences that ripple across soils, water, crops, livestock, and household economies.

To translate this systemic local perspective into a measurable framework, the team developed a novel tool: the Locally-Anchored Impact Index, or LAII. The index integrates two dimensions for each Component of Change: the perceived severity of its impact and its degree of interconnectivity within the broader socioecological system. This approach represents a deliberate departure from conventional vulnerability indices that rely solely on external expert judgments or remotely sensed data. By weighting severity with connectivity, the LAII captures the cascading quality of risk, identifying which pressures are most likely to propagate disruption through the entire farming system.

The results are striking. Surface and groundwater flow dynamics and drought emerged as the most influential Components of Change, ranking highest in both perceived severity and interconnectivity. Water, in other words, functions as the central node of the regional risk network. Declining water availability does not merely stress irrigation; it reshapes pasture productivity, soil stability, forest health, fire regimes, and ultimately the viability of the family farm itself. The researchers found that climatic and ecological factors exerted a greater overall impact on the system than socio-economic pressures such as market volatility or land-use change, a finding that underscores how acutely environmental transformation is being felt on the ground.

One of the most consequential discoveries concerns the relationship between the diversity of adaptive practices and the magnitude of local impact. Higher values on the Locally-Anchored Impact Index were associated with a broader repertoire of adaptive responses, suggesting that farmers facing the most interconnected pressures have also developed the richest portfolios of strategies. Climatic Components of Change mobilized the widest range of responses of any category, while ecological and socio-economic pressures elicited distinct, more specialized sets of adaptation practices. This pattern supports a growing body of resilience theory holding that pathway diversity, the availability of multiple viable responses, is a key determinant of a system’s capacity to absorb disturbance without losing its essential functions.

Adaptation, in this context, is not a modern imposition but an extension of long-standing Local Ecological Knowledge, or LEK. The farmers’ responses are grounded in generations of local learning, experimentation, and knowledge exchange. Ethnobiological research in Patagonia has repeatedly documented how smallholders read animals, birds, and plants as ethno-indicators of environmental change, manage firewood and soil resources with detailed local taxonomies, and maintain agrobiodiversity as a buffer against uncertainty. The new study extends this tradition by showing that knowledge transmission pathways themselves differ according to the type of pressure at hand. Climatic stresses, ecological disturbances, and economic shifts each draw on distinct channels through which practices and insights move between generations and across families.

This finding carries significant implications for how adaptation policy is designed in rural Latin America and beyond. Much of the existing literature on farmer perceptions of climate change treats adaptation as a relatively uniform response to generalized climatic stress. The Patagonian evidence suggests instead that the social architecture of knowledge, who teaches whom, in what settings, and through which relationships, is integral to the adaptive process. Interventions that ignore these pathways risk delivering information in forms that never take root. Conversely, supporting existing knowledge networks, including the market institutions that bring farmers together, may be among the most cost-effective strategies for building regional resilience.

The broader context gives the findings added urgency. Recent research documents rising temperatures and shifting precipitation patterns across the North Patagonian Andes, projections of increasing fire probability under twenty-first-century climate scenarios, and accelerating land-use transformation around protected areas in both Argentina and Chile. Family farming systems in the region sit at the intersection of these pressures, contending simultaneously with a warming and drying climate, fire-driven pine invasions, volcanic ash events such as the 2011 Cordón Caulle eruption, tourism-driven development, and the economic precarity characteristic of smallholder agriculture throughout the Global South. The systemic perspective of local farmers, the study argues, is not folk wisdom to be accommodated but an analytically sophisticated account of precisely these cascading dynamics.

Methodologically, the LAII offers a transferable framework for participatory assessment of socio-environmental change in other regions where smallholder livelihoods depend on intimate knowledge of local ecosystems. Because the index is built from locally perceived severity and interconnectivity, it can be adapted to contexts as varied as Andean altiplano communities, African mountain regions, or Mediterranean watersheds, all places where comparable studies have shown that local knowledge reveals patterns invisible to conventional monitoring. The researchers emphasize that the approach treats family farmers as active agents rather than passive victims of change, in line with contemporary decolonizing currents in ethnobiology that position local communities as co-producers of environmental science.

For the farmers of the Nahuel Huapi basin, the study confirms what their daily experience already teaches: water is the thread that binds every risk together, and the knowledge networks that carry adaptive practices from one family to the next are as vital to survival as any well or canal. For scientists and policymakers, the message is equally clear. Effective adaptation will require tools that measure risk the way the people who live with it actually experience it, as a connected, cascading system in which the fate of a single stream can determine the fate of a farm, a market, and a way of life.

Subject of Research: Locally grounded assessment of cascading socio-environmental risks and adaptation in Patagonian family farming systems

Article Title: Cascading Socio-environmental Risks In Northern Patagonia: A Locally Anchored Assessment From Family Farming Systems

Article References: Rico Lenta, C., & Ladio, A. (2026). Cascading Socio-environmental Risks In Northern Patagonia: A Locally Anchored Assessment From Family Farming Systems. Environmental Management, 76(9), Article 306. https://doi.org/10.1007/s00267-026-02619-6

Image Credits: AI Generated

DOI: 10.1007/s00267-026-02619-6

Keywords: family farming, Northern Patagonia, water scarcity, Local Ecological Knowledge, participatory assessment, socio-environmental change, drought, adaptation strategies, resilience, ethnobiology, impact index, socioecological systems