A close-up look at how scientists arrived at the evidence for global warming.
Broecker (Environmental Sciences/Columbia Univ.) teams with science writer Kunzig (Mapping the Deep, 2000, etc.) to document decades of climate research, much of it conducted by Broecker himself. Broecker became a pioneer of radiocarbon dating, the discipline that transformed the geological time scale into a useful chronology. Measuring the proportions of two isotopes of carbon, scientists could date events in the remote past, particularly the ice ages during which glaciers covered much of Europe, Asia and North America. Other techniques, such as the study of mile-long cores taken from Greenland glaciers and of annual sediment layers on lake bottoms, gave a precise look at climate fluctuations over hundreds of thousands of years. The focus on carbon as a chronological measuring rod also led to awareness of the relative historic abundance of carbon dioxide, which had been known since the 1850s to retain the sun’s heat in the atmosphere. Between 1958 and 2004, Dave Keeling of the Scripps Oceanic Institute recorded a 20 percent increase in the atmospheric level of the gas linked to the burning of fossil fuels. Meanwhile, Broecker formed a theory of the “conveyor belt,” a system of oceanic currents moderating the climate of Western Europe. Kunzig uses the theories of Broecker and others to show how the evidence for global warming accumulated, how it relates to the history of past ice ages and its likely effects over the next century. The book ends with looks at techniques that may mitigate the warming, from reduction of emissions—unlikely, say the authors, with India and China reaching for technological parity with the West—to wholesale scrubbing to get them out of the atmosphere.
A strong but never strident document of the coming crisis, expressing some optimism on our chances of surviving it.