Integrate books on religion and the environment into the syllabi of existing seminary courses , from biblical studies to pastoral care. A good resource is the bibliography of The Oxford Handbook of Religion and Ecology by Roger Gottlieb, Oxford University Press, 2006; also, www.webofcreation.org.
Add an eco-justice requirement. Many seminaries require students to face the personal, cultural and institutional aspects of racism, sexism and homophobia, yet most seminarians are not required to explore the "moral assignment" of preserving God's creation. Ideally, an environmental justice course should be required for graduation. Short of that, eco-justice should be an element in some other required course.
Add a new elective, using full or adjunct faculty. See an example of a recent summer course offered at Wesley Theological Seminary.
Offer environmentally related field education, clinical pastoral education, or church internships. These practical aspects of a seminary education can be tailored to train students specifically for eco-justice work on campus, in association with nonprofit organizations in the community, or with a church that explicitly chooses to explore its environmental mission in the local or global community.
Offer a certificate program exploring the relationship between ecology and religion that runs concurrently with work toward a master's of divinity. See the description of the environmental ministry emphasis at the Lutheran School of Theology at Chicago.
Provide postgraduate "remedial training" and professional leadership