Assessing climatic and technological constraints to agricultural productivity in South Asia

This thesis comprises of four essays that seek to advance understanding of the role that climatic constraints have on agricultural productivity in India and Pakistan. This work emphasises that the constraints posed to agricultural production must be understood within the context of an evolving set of environmental and technological conditions. The thesis employs empirical methods to understand these relationships, where particular emphasis is placed on methods suitable for learning about the challenges agriculture will face in the future. The first chapter studies the impact of climate change on rice yields in India by modelling the inter-annual distribution of yield conditional on projected temperature increases. The results suggest a decrease in average yield and a substantial increase in the probability of low yields. It is also shown that yields have become increasingly resilient to heat over time. The second chapter studies the e↵ect of drought on cereal production in India by estimating thresholds of drought impact. By examining thresholds over time, evidence is found of decreasing average impacts, but with evidence of an abrupt increase in average drought impacts in more recent years. Thresholds of precipitation are also estimated, indicating substantial heterogeneity in resilience to drought across crop types and regions of India. The third chapter examines how changes in agricultural technology brought about by the Green Revolution a↵ected the relative importance of agro-climatic factors in determining crop yields. Using a detailed measure of crop suitability it is found that yields increased relatively more in areas of higher suitability, indicating complementarity between agricultural technologies and favourable agro-climatic characteristics. The final chapter uses farm-level data from a specifically-designed survey to assess the impact and determinants of climate change adaptation strategies on crop productivity in Pakistan. Adaptation has a beneficial e↵ect on rice yields, but not on wheat yields. This chapter also finds that a number of household and institutional factors are strongly related to whether households have adapted to climate change

Does choice of drought index influence estimates of drought-induced rice losses in India?

Drought events have critical impacts on agricultural production yet there is little consensus on how these should be measured and defined, with implications for drought research and policy. We develop a flexible rainfall-temperature drought index that captures all dry events and we classify these as Type 1 (above-average cooling degree days) and Type 2 droughts (below-average cooling degree days). Applied to a panel dataset of Indian districts over 1966-2009, Type 2 droughts are found to have negative marginal impacts comparable to those of Type 1 droughts. Irrigation more effectively reduces Type 2 drought-induced yield losses than Type 1 yield losses. Over time, Type 1 drought losses have declined while Type 2 losses have risen. Estimates of average yield losses due to Type 1 droughts are reduced by up to 27 per cent when Type 2 droughts are omitted. The associated ex-post economic costs in terms of rice production are underestimated by up to 124 per cent

Threshold effects of extreme weather events on cereal yields in India

Climate change is driving a rise in the intensity and frequency of extreme weather events. Such events are characterised as thresholds beyond which cereal yields significantly change. We apply a threshold model to district-level data collected in India over 1966-2011 and objectively identify thresholds, measured by the Standardised Precipitation-Evapotranspiration Index, before estimating their yield effects, for rice, wheat, maize, millet, sorghum and barley. Heterogeneous, crop-specific thresholds are identified for all crops except wheat. Thresholds are identified at normal climatic conditions but have smaller negative marginal effects than those of thresholds identified at dry conditions. The extent to which agro-ecological conditions and irrigation influence the location of thresholds and the size of their marginal effects varies by crop. Thresholds identified at dry climatic conditions severely reduce yield yet are rarely crossed; those at normal conditions moderately affect yield but are frequently crossed. A threshold’s total impact on production is found to be inverse to the severity of its marginal effect. Severe-effect thresholds have been crossed with increasing frequency over time, contributing to growth in the size of total impacts. Our results have welfare implications and have the potential to inform predictions about the impacts of extreme weather events

Crop productivity and adaptation to climate change in Pakistan

The effectiveness of adaptation strategies is crucial for reducing the costs of climate change. Using plot-level data from a specifically designed survey conducted in Pakistan, we investigate the productive benefits for farmers who adapt to climate change. The impact of implementing on-farm adaptation strategies is estimated separately for two staple crops: wheat and rice. We employ propensity score matching and endogenous switching regressions to account for the possibility that farmers self-select into adaptation. Estimated productivity gains are positive and significant for rice farmers who adapted, but negligible for wheat. Counterfactual gains for non-adapters were significantly positive, which is potentially a sign of transactions costs to adaptation. Other factors associated with adaptation were formal credit and extension, underscoring the importance of addressing institutional and informational constraints that inhibit farmers from improving their farming practices. The findings provide evidence for the Pakistani Planning and Development Department's ongoing assessment of climate-related agricultural losses