Climate change poses one of the most critical challenges of our time, necessitating systematic change and individual actions to combat the crisis. Games, both digital and analogue, have the potential to empower individuals as pro-environmental actors. However, academically driven, research-based serious games often have limited scope and audience, while commercially successful games lack valid research on incorporating environmental messaging. This dissertation aims to bridge the research-industry divide by conducting design workshops with game industry professionals through the United Nations Green Game Jam. The workshops introduce an evidence-based environmental game design framework, connecting environmental psychology and serious game design strategies. The objectives are to understand how designers interact with research-supported strategies, foster industry-research collaboration, and gain insights into advancements in serious game design. Four themes emerge from the investigation, reflecting the iterative design process, theoretical connections, comparisons with popular games, and the teams' shared understanding of relevant theories. The designs proposed through the workshop align strongly with evidence-based environmental education and serious game design theories, offering potential for empowering climate action. The dissertation follows a traditional structure, including a literature review on environmental education and serious game design theories, the creation process of the Environmental Game Design Playbook, workshop methodologies, data collection, and analysis approaches. The study's contributions include evidence of learning and agency among participants, insights into design processes, and a theoretical framework for mixed reality climate action games. These contributions have significant implications for industry and academic practice in pro-environmental game design.