“Religion, Science and the Future,” Featured speaker, 10th Anniversary Conference of the International Society for the Study of Religion, Nature and Culture, The University of Florida, January 2016.
“Wonder and the Natural World,” Keynote Lecture at “Wonder and the Natural World Symposium,” Indiana University Consortium for the Study of Religion, Ethics, and Society, May 2015.
“Terrapolitan Earth Civilization and the Religious and Natural Future,” invited public lecture, and a seminar titled “The Greening of Religion Hypothesis,” sponsored by the Friends of the Department of Religious Studies, the University of Kansas, April 2015.
“Dangerous Territory: The Contested Perceptual Spaces Between Imperial Conservation and Environmental Justice” invited lecture, Environmental Studies Program, University of California, Santa Cruz, 28 April 2015.
“Dark Green Religion from the first to this Earth Day,” University of South Carolina Upstate (Spartanville), 21 April 2014.
“Toward a Terrapolitan Earth Civilization,” invited lecture, Environmental Arts and Humanities Program, Oregon State University, January 2014.
“A Research Romp through Interdisciplinary Environmental Studies: From Grassroots Environmentalism to Ecological Enlightenment?”, invited lecture, Environmental Studies Program, the University of California, Santa Barbara, February 2013.
“Spirituality After Darwin,” invited lecture, Cultures of Energy/Mellon-Sawyer Seminar Series Seminar, Rice University, Houston Texas, February 2013.
“Panentheism and Dark Green Spirituality,” invited presentation, workshop on Evolutionary Panentheism, the Esalen Institute, Big Sur, California, November 2012.
“The media and message of Dark Green Religion: tracking the spread and influence of contemporary nature spirituality,” invited lecture, Presbyterian College, Clinton, South Carolina, September 2012.
“The Greening of Religion Hypothesis,” presenter and convener of the “Forum on The Greening of Religion Hypothesis,” 5th meeting of the International Society for the Study of Religion, Nature, and Culture, Pepperdine University, Malibu, August 2012.
"Spirituality After Darwin: ‘Dark Green’ Nature Religion as a New, Global Religious Movement," keynote presentation at the conference, “Interdisciplinary Perspectives on New Religions: Globalization and Sustainability,” University of South Florida, 1 March 2012.
“Dark Green Religion,” Reinhold Niebuhr Lecture Institute, Sienna College, Loudonville New York, 10 March 2011.
“North American Perspectives on Reclaiming Ecological Wisdom for the Crisis of our Time,” workshop sponsored by Stanford's Millennium Assessment of Human Behavior initiative, Stanford University, 23-24 May 2010.
“Religion and Climate Change,” Plenary Presentation, Consilience Among the Social Sciences in the Face of Global Climate Change, Launch Workshop, the Rocky Mountain Series on Social Science & Global Change, Colorado State University, April 2010
“Integrating the Humanities into Environment-related education,” Plenary Presentation, Conference on Teaching and the Environment, LeMoyne College, Syracuse New York, October 2009.
“Dark Green Religion: Nature Spirituality and the Quest for Sustainability." Keynote Address, Conference on Humanities and Sustainability, Florida Gulf Coast University, May 2009.
“Beyond Taboo: The Interdisciplinary Imperative in Environmental and Sustainability Studies.” Wrigley Lecture, Arizona State University, November 2008. Also presented “The Humanities & Sustainability Studies: Gaining Place at the Table.”
“Justice, Faith, and the Quest for Sustainability: From Rio to Johannesburg and Beyond,” keynote presentation, Young Adult Ecumenical Forum on Environmental Justice 2007, March Chapel at Boston University, July 2007.
“Earth First! and the Earth Liberation Front: Exploring the Religious Dimensions of the Radical Environmental Movement through Sound, Performance and Art,” and “Surfing as Nature Religion,” Carleton College (Minnesota), February 2007.
“A Green Future for Religion and the Earth?,” plenary presentation for the inaugural conference of the International Society for the Study of Religion, Nature and Culture, The University of Florida, April 2006.
“Globalization and Earth-Based Spiritualities,” Hamilton College, invited lecture, March 2006.
“The Future of the Humanities in Environmental Education,” University Lecture, The University of North Texas, February 2005.
“Earth First!, Ritual, and Nature Religion,” Rubenstein School of Environment and Natural Resources, The University of Vermont, October 2004.
“The United Nations and the Future of Sustainability Politics,” keynote presentation, Roots and Shoots Conference (Jane Goodall Institute), Warren Wilson College, April 2003.
“Revolutionary Environmentalism: Promise or Peril?,” keynote presentation, “Revolutionary Ecology” conference, California State University, Fresno, January 2003.
“Radical Environmentalism and Bioregionalism: The Promise and Peril of Dark Green Religion,” Anthropology Forum, California State University Chico, April 2002.
“Terrorism and Beyond: the 21st Century,” invited discussant, “Terrorism and Beyond” conference, Oklahoma City, April 2000.
“Environmental Resistance: Lessons from the Front Lines,” Earth Day keynote address, Swarthmore College, Swarthmore Pennsylvania, April 1999.
“Bioregionalism: an Ethics of Loyalty to Place,” presentation for a roundtable conference on “Bioregionalism and its Influence in Europe in the United States,” Dumbarton Oaks (The Harvard University Center for the Study of Landscape Architecture), Washington DC, April 1997.
“Locating the Sacred: the Controversy over the Mount Graham International Observatory,” plenary speaker and panelist for OnSite/InSight: Nature, Humanity, and Time; a Symposium on Landscape History. Pennsylvania State University, June 1996.
“Art, Religion, Ritual, and Ecological Resistance in the North American Deep Ecology Movement,” invited seminar presentation, Institute for Research in the Humanities, University of Wisconsin Madison, October 1994.
“Earth or Outer Space as Sacred Place: the Battle over the Mount Graham International Observatory,” faculty colloquium, the Catholic University of America, Washington, D.C., November 1993.
“The Primal Spirituality and Musical Ritualizing of Earth First!,” featured speaker, sponsored by the Wisconsin Institute for the Study of War, Peace, and Global cooperation. Presentation at St. Norbert’s College, DePere Wisconsin, April 1993.
“Affirmative Action at Work: Battleground of Competing Values,” keynote address, Ethics in Public Life lecture series, Kansas Wesleyan University, September 1992.
“Earth First!’s Spiritual Politics,” seminar sponsored by the Center for Energy and Environmental Studies, Princeton University, August 1991.