Climate, uncertainty, and the slippery measurement of Antarctic ice

Abstract

This thesis presents a history of scientific uncertainty as told through several key episodes in the mapping, measuring, and modeling of Antarctica's ice sheets. Throughout, I trace the scientific practices constraining uncertainty—and the ways in which uncertainty has repeatedly escaped constraint. After the International Geophysical Year (1957-8), as scientific activity intensified at both poles, glaciologists and geophysicists sought new tools and techniques to reckon with Antarctica’s vast scope, its relative inaccessibility as a field site, and the clues to distant events in Earth history that could be extracted from the ice sheet. Though regarded as peripheral to earthly affairs for much of this history, Antarctica can be seen as a central case for exploring the limits and elisions of postwar projects of global knowledge. The development of a novel technique of 'radio echo sounding' in the polar regions during the 1960s and 70s was one of the first large-scale deployments of remote sensing in the study of planetary landscapes. In the first chapter, I demonstrate how researchers' use of a prototype instrument (a radar depth-sounder) on an unknown target (the underside of the ice sheet) involved working iteratively between different registers of uncertainty to reach into the depths of the ice. The second chapter examines the way in which satellite technologies, which were optimized for the exploration of “earth resources” through NASA’s Landsat program, were designed with blind spots for the icy landscapes of the Southern Hemisphere. The resulting gaps in Antarctic satellite imagery highlight the constructed nature of satellite vision and demonstrate the kinds of interpretive work hidden within composite images of the Earth’s surface. By the 1990s, as scientists began to question Antarctica's stability with more urgency, the region came into focus with the construction of continental mosaics that were capable of representing the Antarctic as a whole. Adding to considerations of uncertainty raised by these investigations into the horizontal and vertical dimensions of ice, the third chapter addresses some temporal aspects of Antarctic research. With the increasing centrality of ice sheet modelling to glaciology, the drive to extend time series into the pre-satellite past led scientists to excavate earlier research in search of older data points. I argue that scientists necessarily practice a socio-scientific "data archaeology" in the re-use of older observations, navigating the unknowns of the historical archive as anthropological interpreters of their own research communities. In the final chapter, these forms of uncertainty combine in the case of the West Antarctic Ice Sheet and hypotheses of ice sheet instability. As science and policy mixed and mingled in the Intergovernmental Panel on Climate Change (IPCC) assessment process, advocates for quantitative and qualitative forms of uncertainty increasingly came into conflict over the proper or effective uses of uncertainty. I argue that the formulation of the category of "deep uncertainty" represents an ideological shift in the physical sciences of climate and cryosphere, signaling the deepening entanglement of human actions and natural systems.