Behind the Curve: Science and the Politics of Global Warming

Introduction: Telling Stories about CO2

3 Introduction Telling Stories about CO2 Few people who do not work in climate science or global warming advocacy recognize the Keeling Curve by name. Even for the well-informed, the name typically rings only a faint and distant bell. And yet, when you actually see the undulating, upward-sloping line running from left to right, between x and y axes, in the context of a discussion about global warming, the image and its meaning become instantly familiar . The Keeling Curve represents the measured concentration of carbon dioxide in the atmosphere at the Mauna Loa Observatory since 1958, when Charles David Keeling began measuring CO2 with his manometers there.1 The undulations represent annual cycles of growth and decay on the land masses of the Northern Hemisphere, where plants fix carbon in leaves and stems in the spring and summer months and then release carbon back into the atmosphere as they drop those leaves in the autumn and winter. In 1958, Keeling found that for every million units, or “parts,” of the mélange of gases we call the atmosphere, 315 were CO2 . In 2013, that number—​ parts per million CO2 —​ surpassed 400.2 The information needed to interpret the significance of the Keeling Curve is neither particularly complicated nor particularly new. Between 1859 and 1862, the Irish physicist and mountaineer John Tyndall used a new instrument called a ratio photospectrometer to confirm experimentally that CO2 absorbed radiation and therefore acted to regulate the 4 | Introduction temperature of the atmosphere and the earth.3 In 1896, a diligent Swedish chemist and Nobel laureate named Svante Arrhenius did a set of tedious pencil-and-paper calculations that showed that a doubling of CO2 would cause about a 5ºC increase in the mean temperature of the earth.4 And in 1957, just before Keeling’s project took off, his oceanographer boss, Roger Revelle, and a radiochemist named Hans Suess demonstrated geochemically that humans were, as a few scientists before them had claimed, contributing CO2 from fossil fuels to the global atmosphere. Of course, each of these ideas has undergone significant modifications in the past half century as our understanding of the dynamics of the global atmosphere has grown. But I am only half joking when I tell my students that in order to understand the significance of the Keeling Curve, they need little more than the physics of the 1860s, the mathematics of the 1890s, and the chemistry of the 1950s. Equipped with that information, they will find the Keeling Curve to be one of the simplest and most powerful images in the iconography of anthropogenic climate change. As a visualization of data, the Keeling Curve derives its power from its simplicity. The curve measures a single variable—​ atmospheric CO2 —​ over time.ButthesimplicityoftheKeelingCurvemasksmuchmoreaboutCO2 induced climate change than it reveals. Behind the curve lies a series of contextually specific interactions between individuals, institutions, ideas, and interests. Behind the curve lies the growth of a fossil fuel–​ dependent industrialized world producing CO2 and the long hours spent by scientists and institutions measuring, describing, and predicting the causes and effects of the rise in atmospheric CO2 . Behind the curve rests the passion of a community of concerned scientists and citizens interested in mitigating the climatic and environmental changes caused by rising CO2 . And behind the curve also sits the interactions between a large cast of local, national, and international political actors and institutions charged with creating a framework for regulating CO2 and other greenhouse gases. The curve remains relatively constant in its shape and slope, but with every annual oscillation, the constellation of forces behind the curve has changed. To divorce the Keeling Curve from the complexities that it masks and the contexts in which it appears is to miss what makes the image both so incredibly powerful and so puzzlingly problematic. The Keeling Curve seems simple and elegant, but the problem that it describes is not simple at all. This book traces the scientific and political history of climate change Introduction | 5 over the life of the Keeling Curve. It is a story about the scientific, political , environmental, and economic complexities that the simple measure of atmospheric CO2 since 1958 tends to hide and how those complexities have changed over time. The Keeling Curve is only one in a variety of simplified descriptions of the earth’s climatic and environmental systems; but like the Keeling Curve, each of these models masks...