Adaptation to Climate Variability in Social Agro-Ecological Systems

Variability is inherent to any living system, and adaptation, or changing one's behavior in response to variability, is an important way to reduce or eliminate possible adverse consequences of change. Adaptation is particularly important to consider in the face of contemporary climate change, as individuals and communities may be able to adapt their behavior in response to weather variability and reduce or possibly eliminate predicted adverse impacts. To gain a more mechanistic understanding of which factors may lead to enhanced adaptive capacity of individuals and communities to future change, this dissertation uses a multi-disciplinary and multi-scale approach to broadly examine which social, economic, biophysical, and perceptional factors are associated with agricultural adaptation to current weather variability. The results from this dissertation generally show how adapting agricultural practices, like changing cropping patterns or increasing irrigation, can reduce the vulnerability of farmers to weather variability. Importantly, however, we show that adaptation is not simply about adopting appropriate technical solutions like sowing weather-appropriate crops or irrigating optimally, it is also about the complex set of economic, social, and perceptional factors that influence farmer decision-making and adaptive capacity. A global literature review highlights important biases and gaps in our current knowledge about climate change adaptation research in the agricultural sector. Based on these findings, we offer recommendations for future research that may result in a more process-based understanding of adaptation, including conducting multi-disciplinary studies that simultaneously consider the social, economic, biophysical, and perceptional factors that are associated with adaptation, and understanding how weather variability and change influence well-being to more accurately identify which individuals, households, or communities are best able to adapt. Using these recommendations, we design a case study that examines how farmers alter their cropping strategies in response to monsoon variability in Gujarat, India. Much of our research is focused on India given that over 50% of the nation practices smallholder agriculture and is particularly sensitive to climate variability and change. Through this work, we find that farmers altered their cropping decisions in response to a delayed monsoon onset, by increasing irrigation, switching crop type, and/or delaying crop sowing, and these strategies, particularly increasing irrigation, were adaptive considering yield and profit in the year of our study. These results highlight the importance of considering farmer behavior and decision-making in models that estimate future weather and climate impacts on agricultural production. While household-level surveys allow one to assess individual-level decision-making, they are difficult to implement over large spatial and temporal scales. Thus we develop a remote sensing algorithm that quantifies cropped area of smallholder farms over large spatial and temporal scales using readily-available MODIS imagery. Given the importance of irrigation as an adaptation strategy, we link these cropped area maps with rainfall and irrigation data at the village scale across all of India to assess the relative impact of different types of irrigation (e.g. groundwater versus canal) on winter cropped area and its sensitivity to rainfall variability. Overall, we find that deep well irrigation is both associated with the greatest amount of winter cropped area, and is also the least sensitive to monsoon and winter rainfall variability. However, the relative benefit of deep well irrigation varies across India, with the largest benefits seen in the regions that are facing the greatest levels of groundwater depletion. This work highlights the critical importance of groundwater for agriculture in India, and suggests that future work should identify ways to use groundwater more efficiently, increase the recharge rate of groundwater, or improve the performance of canal irrigation in order to maintain similar levels of production in the face of climate variability and change over the upcoming decades. While this dissertation focuses on agricultural adaptation to weather variability, the methods and implications derived from this dissertation are applicable more broadly to the study of resilience and adaptive capacity of social-ecological systems to global environmental change. In a rapidly changing global system, using a multi-disciplinary, multi-scale, and coupled systems approach similar to the one employed in this dissertation will help better understand and identify possible ways to enhance the ability of societies to adapt to global environmental change