Following up on the International Conference on Synthetic Populations (February 22-23, 2017) the communities of Global Systems Science and High Performance Computing scientists meet again, this time also with practitioners, to contribute to the ongoing discussion on computational modelling for addressing Global Challenges. This year, when celebrating its 60th birthday, the EU made a bold claim about its future: it will become a global player on the next stage of high-performance computing, known by the label of exascale computing. This raises the question in which fields Europe may choose to develop a comparative advantage in future high-performance computing - in which fields to form new communities, know-how, infrastructures and markets. One such field could be the understanding and mastering of global challenges. The conference will focus on four example global challenges: - developing a sustainable and resilient global financial system; - addressing the daunting risks of pandemics; - transforming the fossil-fuel based global mobility system; - creating forms of democracy adequate to the age of digitalization.