Few global challenges loom larger than the social and environmental consequences of climate change. Particularly in semi-arid regions, increasing temperatures and attendant changes in drought severity and drought persistence threaten the sustainability of human communities, agricultural systems, and fire-prone forests.  Although these may appear to be exclusively contemporary problems, human communities have lived in semi-arid environments for millennia through variable climates, including droughts more severe and longer in duration than yet experienced as a result of global warming. The interplay between climate, societies, and their environments is not simple and deterministic, however. The complex relationships between social and ecological systems contain feedbacks that can amplify or suppress the impacts of climate extremes. Pioneering interdisciplinary research by archaeologists, dendrochronologists, and complex systems modelers working in the semi-arid Southwestern U.S. has begun to document these dynamic relationships over millennial timescales and across climate transitions. Food and water security, changing fire risk, deforestation, and ecosystem conversion are climate concerns of the past and the present. This symposium highlights the contributions of interdisciplinary investigations of multi-century nature-society couplings for addressing contemporary vulnerabilities to climate change and its social and ecological consequences.