This project is developing, refining and evaluating a suite of simulations and systems-thinking exercises which enable students to investigate earth's climate and human-energy systems and their complex responses to changes in forcing factors. Scientifically sound and easy-to-use software models provide rapid feedback as students grapple with system responses over time to a variety of input assumptions. The ability of students to assume the roles of multiple stakeholders and quickly explore 'what if' scenarios as climate sensitivity and forcing factors are varied promotes understanding of underlying systems concepts. The intellectual merit of this project lies in its well-grounded plans for active engagement of students which confronts them with common misconceptions of complex systems and promotes more-robust understanding of system dynamics. The broader impacts include ready availability of the software and approaches for adoption elsewhere and wide applicability of the approach across a range of disciplines.