 He further specialised in the numerical simulation of climate change in an interdisciplinary perspective, and has worked at global and regional scales.He is particularly interested in the effect of human activities on climate, the impact of climate variability and change on ecosystems and human activities, and what can be done about it (adaptation and mitigation).van Ypersele authored papers on subjects on a plethora of issues, including the modeling of sea ice, palaeoclimates, the climate of the 20th and 21st century, regional climate change in Europe, Greenland, and Africa, and the ethical issues associated with responsibility for climate change.