RUI: The Carbon Dioxide Theory of Climate Change

Colby College, Waterville ME

Investigators

Abstract

Abstract JamesFleming, Colby College The Carbon Dioxide Theory of Climate Change: Emergence, Eclipse, and Reemergence This study documents the discovery and early development of the carbon dioxide theory of climate change, its eclipse during the first five decades of the twentieth century, and its reemergence after 1950. It also examines subsequent developments in modeling, monitoring and climate reconstructions, while examining more recent social and political implications of the theory. Based on archives, interviews, expert consultations, and primary printed sources, the study provides an historical context for understanding current climate concerns. It also demonstrates the importance of intellectual and social changes in the study of global environmental change. In the nineteenth century, the work of John Tyndall, Svante Arrhenius, T.C. Chamberlin and others drew scientific attention to the role of carbon dioxide as a possible mechanism of climate change. Throughout the first half of the twentieth century, however, most scientists did not think that increased carbon dioxide levels would result in global warming. It was believed that current levels of carbon dioxide already absorbed all the available long-wave radiation, so any increases would not significantly alter the radiative heat balance of the planet. Most meteorologists gave other mechanisms of climatic change more credence. Beginning in 1938 the work of Guy Steward Callendar, Gilbert Plass, Hans Seuss, Roger Revelle, Charles Keeling and others revived the carbon dioxide theory of climate change and placed it on a more solid scientific basis. Callendar based his theory on new detailed measurements of the infrared spectrum, further noting that the warming trend from about 1900 to 1938 might be related to rising fossil fuel emissions. Seuss and Revelle later named the rising levels of atmospheric carbon dioxide caused by industrial fuel combustion the "Callendar effect." In the second half of the twentieth century, computers, satellites, and reconstructions of past climate records provided new privileged perspectives on the climate, allowing the emergence of a scientific consensus (but not unanimity) on the carbon dioxide theory of climate change. The state of climate science (in theory and in practice) during this convergence of opinion will be contrasted with that during the earlier eclipse and re-emergence phases. By the 1950s, station temperatures around the Northern Hemisphere reached early-twentieth-century peaks, giving credence to Callendar's warnings and placing climate warming on the public agenda. Concerns were expressed in both the scientific and popular press about rising sea levels, loss of habitat, and shifting agricultural zones. This was followed by a global cooling scare in the 1970s and the re-emergence of global warming consensus through the work of the Intergovernmental Panel on Climate Change and the Framework Convention on Climate Change. The project concludes with a reconsideration of the human dimensions of climate change in light of history, including popular perceptions, economic and public policy initiatives, and politicization of the issues. Outcomes include paper at professional historical and scientific meetings, refereed journal articles, materials posted on a WWW Center for the History of Meteorology web site, and a fully-documented book.