In this episode, Michael speaks with Billie Turner II, Regents Professor at the School of Sustainability at Arizona State University. Billie holds other positions as well, including Distinguished Global Futures Scientist at the Julie Ann Wrigley Global Futures Laboratory, also at Arizona State, member of the US National Academy of Sciences, and Associate Editor of the Proceedings of the National Academy of Sciences. Billie is a geographer and human-environmental scientist who studies land use and land cover change from prehistory to the present, and he has also contributed to our understanding of the determinants of social vulnerability and resilience. He works on deforestation, primarily in Mexico and Central America, and urban design in arid environments, especially the American Southwest.Michael and Billie talk about two topics that Billie has written on, one being the reasons for the decline of a lowland Maya population around the years 800 to 1000, and the other being a long-standing debate between Thomas Malthus, who predicted that exponential population growth would inevitably outstrip linear growth in resources, and Esther Boserup, who argued that population-induced scarcity would motivate the necessary innovations to avoid systematic decline.The interview concludes with a discussion of the book that Billie recently wrote, entitled: The Anthropocene, 101 Questions and Answers for Understanding the Human Impact on the Global Environment. References:Turner, B. L., and Jeremy A. Sabloff. 2012. “Classic Period Collapse of the Central Maya Lowlands: Insights about Human–environment Relationships for Sustainability.” Proceedings of the National Academy of Sciences 109 (35): 13908–14. https://doi.org/10.1073/pnas.1210106109.Turner, B. L., and A. M. Ali. 1996. “Induced Intensification: Agricultural Change in Bangladesh with Implications for Malthus and Boserup.” Proceedings of the National Academy of Sciences of the United States of America 93 (25): 14984–91. https://doi.org/10.1073/pnas.93.25.14984.Turner, B. L. 2022. The Anthropocene: 101 Questions and Answers for Understanding the Human Impact on the Global Environment. Agenda Publishing.