The American Geophysical Union's Thriving Earth Exchange advances humanitarian geophysics by helping scientists, communities, and sponsors connect and launch projects that use earth and space science to help address practical priorities, one community at a time. Scientists are any learning, practicing, or retired professional from industry or academia; communities are geographic, cultural, ethnic, or professional groups coalesced around shared priorities; and sponsors are funders or advocates who would like to enable and learn from projects. Using crowd-sourcing and social-networking tools, the Thriving Earth Exchange will catalyze community science so that community leaders, scientists, and sponsors work as partners to generate and apply scientific insight. The exchange will help project leaders to explore ideas, form partnerships, design projects, and connect with the human, technological, and capital resources they need to carry out those projects. Because the exchange supports and links a diverse set of interactions, project leaders can go all the way from exploring broad connections between science and community priorities to launching specific, actionable, science-based projects. All this occurs in an open environment that invites broad participation, facilitates reuse of innovative solutions, and builds trust between scientists and nonscientists.