Melting the glacial curtain: the politics of Scandinavian–Soviet networks in the geophysical field sciences between two polar years, 1932/33–1957/58

•Ties between geophysical scientists in USSR and Scandinavia were vital 1930–1960.•Geographer Hans Ahlmann was a key science diplomat and broker of contacts.•Ahlmann shared a curiosity on Soviet Arctic research with Norwegian oceanographer Harald Ulrik Sverdrup.•Soviet Arctic science drew increasing attention in the West.

While providing a brief background of the development of Scandinavian–Russian relations in the polar sciences in the early 20th century, this paper focuses on the period from the 1930s when the Swedish geographer Hans Ahlmann and Norwegian oceanographer Harald Ulrik Sverdrup developed a curiosity of the Soviet Union as a field for the practice of Arctic science. Visit of the Arctic Research Institute in Leningrad in 1934 further enhanced Ahlmann's sympathy and in 1935 he co-founded the Society for the Promotion of Cultural and Scientific Relations between Sweden and the Soviet Union. After further wartime collaboration, Ahlmann returned to the Soviet Union in 1958 and 1960 as president of the International Union of Geographical Sciences. Using his longtime Soviet contacts to penetrate the Iron Curtain, Ahlmann became a key figure in maintaining the flow of scientific information between East and West. New materials from archives open perspectives for better understanding of the international connections and transfer of knowledge in geophysical and geographical science in its formative period. The key message from this paper is that while tensions did exist and presented scientists with differential loyalties, they still managed to find ways to undertake fruitful scientific collaborations even under political restraints and could sometimes play political roles.