Visualization is a key technology for analyzing climate simulations and observations as well as related social and ecological data. Furthermore, mediating research results to decision makers and to the general public in an easily-understandable way is of growing importance. However, there is still a gap between sophisticated visualization approaches and techniques (multi-view, multi-variate visualization, brushing & linking, ...) and the knowledge and the requirements of domain users in earth system sciences. In this context, the talk presents requirements of climate impact researchers using visualization based on a questionnaire and provides insights into the daily visualization work in such an domain. Tailored solutions and visualization tools will be presented, focusing on the aspects comparative and ensemble visualization of climate simulation data.