The sources, abundance and nature of emissions of ice nucleating particles (INPs) affect aerosol-cloud interactions, precipitation, and climate (via cloud phase and lifetime influences) in ways that are not well characterized. While past research has emphasized the global relevance of mineral dusts and other inorganic particles as INPs, we find that INPs emitted from non-desert soils, within marine emissions (via sea spray), and from biomass burning are dominated by unresolved organic ice nucleating materials. While some of these INP sources are less efficient on a number or surface area basis compared to mineral dusts, they can dominate over large regions. Only marine INP sources have been integrated in any manner into cloud and climate modeling applications. I will review past studies, and summarize two recent campaigns that included measurements of INPs over remote oceans and in biomass burning plumes.