The Climate Action Simulation is a group role playing simulation where participants test out a mix of policies and strategies that could address climate change. In a large group setting, participants play business, civil society, and government leaders representing different sectors that have convened to make commitments that will limit climate change to well below 2 degrees Celsius. Participants discuss, negotiate, and try out possible measures like implementing subsidies, carbon pricing, and energy efficiency technologies to reduce greenhouse gas emissions. Proposals are then tested using the En-ROADS Climate Change Solutions Simulator, which provides participants with science-based feedback on their policy and investment proposals. The Climate Action Simulation enables participants to explore the impacts of proposed policies in a way that is consistent with the best available peer-reviewed science but that does not prescribe what should be done.