Resource exploitation, pollution, acidification, temperature, and salinity changes are altering marine ecosystems, seawater chemistry, and ocean circulation in complex ways that are interconnected and feedback on the causes that initiated them. Understanding these changes is essential to providing food sources, to sustaining economic development, and to predicting future atmospheric greenhouse gas levels and global warming. The complexities and interrelatedness of these questions demand that oceanographic research be multidisciplinary, integrative, and based on global-scale observations conducted through large, frequently multinational, programs. The speakers will present major achievements from large-scale oceanographic programs addressing interrelated physical, chemical, and biological changes in the ocean. They will particularly focus on lessons learned and future challenges in crafting cross-cutting, collaborative, and global ocean observational programs.