There are many ways to develop your skills and knowledge in the environmental sciences without enrolling in a complete graduate program.
Environmentally Related Graduate Minors
Graduate minors are offered by individual departments for students from other graduate programs. At Ohio State, there are currently three graduate minors relating to the study of the environment, all of which are administered by the School of Environment and Natural Resources.
The Graduate School maintains the complete list of graduate minors.
Graduate interdisciplinary specializations function in the same way as minors, but they are collaboratively administered by more than one department.
The Graduate School maintains the complete list of graduate interdisciplinary specializations.
Note: Graduate interdisciplinary specializations are different from specializations within a student's graduate program. The first is like a minor, the second is like a focus area within your major. Here's information from the Graduate School about specializations within a student's graduate program.