How Many Is Too Many? The Progressive Argument for Reducing Immigration into the United States (University of Chicago Press, 2015) argues that current immigration levels—the highest in U.S. history—undermine efforts to achieve a more economically just and ecologically sustainable society. Political progressives favoring a more equitable distribution of wealth, economic security for workers and their families, the preservation of other species on the American landscape, and the political empowerment of common citizens should support reducing immigration into the United States. By using immigration policy as a springboard to explore and clarify progressive goals and values, How Many Is Too Many? also contributes to current discussions about the way forward for progressive politics in America. For a summary of the overall argument, see this essay in the Chronicle of Higher Education or listen to my interview with Maria Stadtmueller on her podcast The Big Chew.

Life on the Brink: Environmentalists Confront Overpopulation (University of Georgia Press, 2012) seeks to reignite a robust discussion of population issues among environmentalists, policymakers, and the general public. Some of the leading voices in the American environmental movement show how population growth is a major force behind our most serious ecological problems, including global climate change, food and water shortages, and the mass extinction of Earth’s species. 25 contributors honestly explore difficult moral and political issues including abortion, immigration and limits to growth, arguing that we must humanely reduce human numbers in order to preserve wild nature and build a vibrant human future. Contributors include Lester Brown, Dave Foreman, Stephanie Mills and Captain Paul Watson. Co-edited with Eileen Crist, with a foreword by Anne and Paul Ehrlich.

Virtue Ethics and the Environment, published in 2010 by Springer-Verlag and co-edited by myself and Ronald Sandler. A collection of articles that explore the multiple connections between human flourishing and environmental protection. Essays discuss new theoretical approaches to environmental virtue ethics and apply this approach to a variety of issues, such as simple living and anthropogenic species extinction. Makes the case that an ethics of character is an indispensable part of an adequate environmental ethics.

Environmental Virtue Ethics, also co-edited by Sandler and Cafaro, published in 2005 by Rowman and Littlefield Press, was the first collection of philosophy articles in this burgeoning subfield of environmental ethics. Environmental virtue ethics presents a positive vision of people living well in a flourishing natural world, challenging the presumption that environmentalism is primarily about restraint, sacrifice and “thou shalt nots.” With contributions from leading philosophers including David Schmidtzt, Holmes Rolston III, Louke van Wensveen, Thomas Hill Jr. and Peter Wenz.

Thoreau's Living Ethics: Walden and the Pursuit of Virtue (University of Georgia Press, 2004) provides the first full, rigorous account of Henry Thoreau's ethical philosophy. In it, I place Thoreau within a long tradition of ethical thinking in the West, from the ancients to the romantics, and explore his value for contemporary readers keen to answer the perennial ethical questions: How should I live my life? What is my proper place in nature? How can I be a good friend, neighbor, and citizen? as well as newly pressing topics in environmental ethics.

United States Immigration Policy: Environmental Impact Statement was published in 2016 by Progressives for Immigration Reform. Written by Leon Kolankiewicz, Winthrop Staples III and myself, it represents the most detailed analysis to date of the environmental impacts of U.S. immigration policy. Topics include urban sprawl and loss of farmland, habitat loss and impacts on biodiversity, water demands and withdrawals from natural systems, carbon dioxide emissions and resultant climate change, energy demands and national security implications, and international impacts of U.S. immigration policies.