Decadal to multidecadal droughts have severe impacts on societies and ecosystems ranging from landscape transformation to economic dislocations and the collapse of civilizations. Megadroughts in the last two millennia have been linked to the decline of Mayan and Anasazi societies, to famines in India, China and West Africa, to the dislocations and agricultural degradation of the American Dust Bowl and to other socially and ecologically devastating impacts around the world. A better understanding of the drivers and probabilities of drought over the last two millennia can improve our understanding of past climate stresses on society. Understanding droughts and their impact, especially with the added driver of higher greenhouse gases and temperatures, is also key to decision making and planning for the future of a world with more people with higher demands for food, water and energy.
As impacts of anthropogenic global warming emerge, together with insights from improved modeling and paleodata, the possibility of unprecedented droughts poses challenges as to how and when to collaborate with stakeholders to plan possible responses. There are many options for drought adaptation, but institutional, biophysical and individual limits may hinder responses to droughts that exceed expectations. Such droughts may demand transformational rather than incremental responses – where the response to unusual drought might require fundamental and proactive changes in land use, agricultural practices, water allocation, conservation priorities or infrastructure in both public and private sectors.
The EASM Megadrought project includes research on the societal impacts of prolonged drought and to understand how stakeholders might respond to new scientific insights into drought. Our projects include reviews and case studies of prolonged drought impacts on society including the 1950s drought in northern Mexico, and the current drought in California. Our work with stakeholders involves translating the insights from climate science of megadroughts into accessible knowledge that might be of use to those managing natural resources and mitigating drought impacts on society. We use a variety of methods and alternative ways of presenting science to test best practices for stakeholder engagement and communication. For example, we compare the clarity and decision utility of raw data, various drought indices, different categories, and types of images (e.g. maps and graphs). We are looking at how stakeholders use current drought information, how they view and take account of the full range of probabilities, and what options they have to respond and adapt to these more severe risks in incremental and transformative ways.