Abstract Developing an advanced understanding of the Earth's fundamental processes and resources is essential to fulfil the United Nations 2030 Agenda for Sustainable Development. The International Geoscience Programme (IGCP) is the oldest and most successful example of scientific co-operation between a non-governmental organization, the International Union of Geological Sciences (IUGS), and an intergovernmental organization, UNESCO. During almost 50 years, this programme has been the gateway to successful scientific careers in pioneering research for thousands of IGCP project scientists. After almost 50 years of evaluating IGCP projects, the programme itself was evaluated through statistical analysis of the annual progress report during four periods: 1981–82, 1991–92, 2001–02 and 2011–12. Subsequently, these trends were compared to the trends of the last four years (2015–18). This study provided insight into trends and changes in the location of studies, participating countries, involvement of developing countries, gender equality, etc. To fully understand the added value of the IGCP brand identity and its seed funding, project leaders over a period of five years (2008–12) were asked to complete a survey about its work. Overall, both studies confirmed the value of the main aim of the IGCP: enabling and facilitating international collaboration between Earth scientists. Even though IGCP funding has been reduced, the IGCP brand still opens doors to new collaborators, new research and national funding agencies, often impacting the career of the involved researchers very positively.