By using concrete examples of the water and carbon cycles, the speakers in this session focus on the grand science questions and how we can turn them into answers and solutions most useful to decision-makers at the front line of the climate crisis. Earth is a highly dynamic system where the transport and exchanges of energy and matter are influenced by a multitude of processes and feedback mechanisms. Untangling these complex processes to better understand how Earth works as a system is a major challenge; a challenge that satellites, with their global view, are ideally positioned to tackle. While each mission gives us unique insights, it is by combining their data that makes scientific findings shine the brightest. This, in turn, puts European and international collaboration at the heart of Earth observation today.