We live in a changing world. Our climate is changing, our populations are growing and moving. Data are becoming ever more ubiquitous and available wherever we are in the world. Weather and climate science using some of the biggest supercomputers and environmental datasets on the planet are producing ever more reliable forecasts at higher resolutions and at time scales that range from minutes to decades. How do we turn this truly amazing science, the bewildering quantities of data, and our understanding of how the world is changing into the next generation of environmental hazard risk assessments and risk- or impact-based forecasts and warnings? This session welcomes presentations on how this question is being addressed around the world, and we would like to see lots of different environmental hazards covered at all scales from the local to the global, from the "warning period" short term to the seasonal and multidecadal longer term.