Key message 3 – More accurate weather forecasts can help farmers make more profitable decisions.

Both the actual realisation of weather as well as expectations of future weather affect agricultural outcomes (Hsiang, 2016). Expectations inform investment and production decisions ex ante. Surveys of farmers across multiple African countries report perceiving changes in the climate and then implementing adaptation measures in response (Maddison, 2007, Hassan & Nhemachena, 2008). Weather realisations then determine whether those decisions become profitable.

Even in the absence of climate change, investment decisions in agriculture are beset by substantial cost and risk. In one study, IGC researchers find investment returns to be highly sensitive to the realisation of rainfall, which is itself highly variable. Owing to this variability in rainfall, in 95% of instances, the realised profitability from investment deviated more than 30 percentages points of what was expected (Rosenzweig & Udry, 2020). This demonstrates how difficult it is for farmers to estimate the returns to investment in rain-fed agriculture.

Increased weather variability arising from climate change will make it even harder to form accurate expectations and make ex ante investment decisions. In general, higher variability will make it less likely that investment returns are realised. Weather forecasting may also become less accurate, increasing the difficulty of planting and production decisions, particularly in rainfall-dependent areas (Scher & Messori, 2019). Africa has the world’s least developed weather, water, and climate observation network, which often reports inaccurate data and leads to losses for farmers (World Bank, 2017).

Better weather forecasting

More accurate weather forecasts should allow farmers to make better investment decisions. In India, IGC researchers find that farmers respond more strongly to forecasts in villages where those forecasts have tended to be more accurate in the past. In those villages, investment decisions respond to forecasts about the onset of the monsoon. Whilst farmers who relied on forecasts had higher average profit levels, they also experienced greater profit variability. When rainfall realisations were high, they performed better than farmers without access to forecasts. However, the opposite was true when rainfall realisations were low (Rosenzweig & Udry, 2014).

Weather and climate information services (WCS) have become an increasingly popular policy tool in low-income countries. WCS incorporate weather forecasts alongside production, translation, and communication of weather and climate information to aid farmers’ decision-making. Existing research on WCS access, usage, and impact shows disparate impacts (Vaughan et al., 2019). Access can differ between pastoralists and farmers, men and women, and the type of service on offer. Where information is easily accessible, it is mostly used (Vaughan et al., 2019). For farmers, information tends to feed into decisions on field and crop selection, water conservation, and the general timing of farming activities. Typically, farmers were using seasonal climate forecasts, weather forecasts, and 1-10-day forecasts.

Estimates of impact vary. In some studies, yields were found to increase by double-digits, such as 17% for yam yields in Ghana (Anuga & Gordon, 2016) and 64% for sorghum yields in Mauritania (Tarchiani et al., 2018). In Senegal, a study found that farmers’ incomes increased when a particularly dry season was correctly forecasted (Sultan et al., 2010). In other studies, losses were experienced amongst some farmers, or tied very closely to the accuracy of forecasts (Ziervogel et al., 2005, Roudier et al., 2014). These latter findings echo those of Rosenzweig and Udry (2014) where the usage of forecasts led to greater profit variability.

Image 1: More accurate weather forecasts should allow farmers to make better investment decisions

Overall, greater access to and accuracy of weather information appears to increase agricultural profitability on average. However, the considerable variation that exists across contexts and users means that more evidence is needed to inform the appropriate design and cost of interventions. If profits are more variable when more decisions are based on forecasts, it is likely that this variation will only widen with climate change. More income variation will require further mechanisms to help reduce risks and cope with shocks.