In its review of a forgotten chapter in the history of the climate sciences during the first half of the 20th century, this article combines two topics: the environmental history of Inner Asia as a research issue for scholarly Europe, and the assessment of theories and data on climate change. Sven Hedin’s writings and the archives and maps of the Sino-Swedish expedition to Western China are the main sources of information. Drafted from data collected in Asia but conceived for European readers, the topographical maps of the Silk Road reveal the contemporary policies and processes of knowledge, identify the local agents of history, and bring out the constraints of a professional identity in the making.