To promote and expand geoscience literacy in the United States, meaningful partnerships between research scientists and educators must be developed and sustained. For two years, science and education faculty from an urban research university and secondary science teachers from a large urban school district have prepared 11th and 12th grade students to mentor 7th grade students on the topic of climate science. This partnership was based on the premise that high school students, when trained and supported by teachers and scientists, have the capacity to extend middle school students? efforts to engage in and understand the geosciences. This paper a) describes mentors? and mentees? understandings of climate science as a function of their participation in the second year of this program, b) identifies the characteristics of effective mentoring relationships, and c) explores the scalable and sustainable aspects of this partnership.