Planetary Timemaking : Paleoclimatology and the Temporalities of Environmental Knowledge, 1945-1990

Abstract: This thesis concerns the history of paleoclimatology in the postwar period. It follows the trajectory of two climate proxy records – ice cores and deep-sea cores – in the North Atlantic region, from their emergence as scientific objects in the 1940s to their incorporation into Earth System Science in the 1980s. In doing so, the thesis highlights how scientists have used these records to produce time and how this has affected the temporalities of the environment as a scientific and political concept. As anthropogenic impact on the planet arose as a political problem, the vast timescales of paleoclimatology became increasingly interwoven with climate modeling and environmental policy. Often, the records were understood as “natural archives”, providing unmediated access to past environmental conditions. This thesis shows how the times of ice- and deep-sea cores were, on the contrary, constantly re-shaped by scientific practices, institutional frameworks andcompeting temporal sensibilities in different scientific fields.With the rise of the Anthropocene concept in the last two decades, historians have begun to question the division between historical and natural times. Scientifically produced times, such as those made by ice- and deep-sea core drilling, have permeated discussions about the properties of historical time in the twenty-first century. Yet, the origins of thesetimes often remain out of view. This thesis argues that environmental historians and historians of science can contribute to these discussions by treating environmental times as objects of historical inquiry. Looking beyond planetary-scale models and following environmental times in situ, as they emerge, form and travel, can open up for more multi facettedapproaches to historical time in the proposed new geological epoch. The history of postwar paleoclimatology is therefore both a history of how scientists have produced environmental times and how planetary pasts enter the political present.