We are increasingly realizing the importance of space weather, i.e., the dynamics of near-Earth space and the sun, as a critical element of Earth’s environment. This is happening as our economic and security infrastructures have expanded far above Earth’s atmosphere into space. Space has no borders. Our satellites all share the same orbits, and the impacts of space weather affect the entire planet, including airline transportation, navigation, communication, and electric power generation. The coupled sun-Earth system is far too vast and complex for any single nation or region to monitor and predict. Through global coordination, we have the opportunity to improve our understanding of this critical component of Earth’s environment and to prepare for the continuous growth in our reliance on space-based assets. This symposium will explore the state of our understanding of space weather as well as strategies for coordinating our global efforts to mitigate its impacts. Recent efforts have focused on the international coordination of our research and services, as well as the development of our emergency-management-response procedures for large-scale infrastructure damage caused by space weather. The presentations and discussion at this symposium are intended to foster a greater awareness of space weather as a critical component of Earth’s environment and to increase opportunities to cooperate across borders to enhance our science and our preparedness.