This open session investigates the complex interplay within the Sun–Earth system, focusing on the dynamic processes that drive space weather and climate. Topics include the progression from solar phenomena, including flares, coronal mass ejections, and the solar wind, to their subsequent interactions with Earth’s magnetosphere, ionosphere, and thermosphere. The session also assesses the cascading risks to critical infrastructure, specifically satellite operations, navigation and communication networks, power grids, and aviation. By bridging observational data, theoretical modeling, and operational insights, this session highlights the necessity of understanding both acute space weather events and the long-term implications of solar variability for our increasingly technological society.