Published last week in the journal ‘Climate Action‘, this article draws attenton to the challenges of political instability and geopolitical tension, together with rising nationalism, bureaucracy and economic pressure, to the free access to and exchange of scientific data (both physical and digital). This also threatens knowledge transfer (within and beyond academia) and research campaigns (of national and international teams around the world). Together with co-authors Ulf Buentgen, Jan Esper and Mirek Trnka, we call for an open-data convention implemented by universities and institutions, academies and organisations, journals and editors, as well as funding agencies and national administrations.