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Foreword from First Edition

Climate change has many manifestations, rising greenhouse gas concentrations, sea‐level rise, abrupt climate change, ocean acidification, reduced Arctic sea ice, droughts, floods, hurricanes, melting glaciers and ice sheets, to mention a few. Few would doubt that climate is the environmental issue of our generation, but what scientific evidence causes so much concern about human influence on climate? Some might argue from the point of view of planetary physics; atmospheric greenhouse gases naturally affect the Earth’s temperature and human carbon emissions have elevated carbon dioxide and methane concentrations and, as a consequence, global temperature. Others might claim that predictive climate models project future temperatures, rainfall patterns and sea levels that threaten society. The striking rise in global temperature observed from instruments over the past century also raises concern about future trends and impacts.

As important as these topics are, one field – paleoclimatology – is unique in providing the requisite baseline of natural climate variability against which human‐induced climate change must be assessed. A rapidly growing discipline that draws on ocean, atmosphere, and Earth sciences, paleoclimatology is today an essential foundation of climate science because it addresses climate history beyond the limited instrumental record and during climate states that the Earth may very well experience in the future. Consider these facts: Ice core records provide the primary evidence that modern greenhouse gas concentrations lie far outside the bounds of natural variability of the last 800,000 years. Thanks to tree rings, speleothems, and other records we now know that rising atmospheric and ocean temperatures during the last century cannot be explained by volcanic or solar activity but required forcing by elevated greenhouse gas concentrations. Lake and marine sediment records confirm what is suspected from satellite records – that polar climates are changing at unprecedented rates. Marine sediment records show us that ocean acidification – a major concern owing to human‐induced perturbations of the global carbon cycle – typically accompanied massive increases in atmospheric carbon dioxide in the geological past.

Reconstructing Earth’s Climate History – a novel classroom and laboratory educational guide by Kristen St John, R Mark Leckie, Kate Pound, Megan Jones and Lawrence Krissek – represents a major, long overdue effort to educate future generations about methods used to reconstruct climate history. From an academic perspective, the book exemplifies the authors’ lifelong dedication to teaching. It includes practical discussions and exercises that teach students how climate history is reconstructed from “proxies” extracted from sediments, ice cores, speleothems, tree rings, coral skeletons, and other archives. It prepares students to engage in field and laboratory research to distinguish natural from anthropogenic climate change, evaluate computer model simulations of climate under elevated greenhouse gas concentrations, and clarify the causes and impact of abrupt climate changes. Equally important, Kristen St. John and her co‐authors also strive to explain why climate history is, and will continue to be, so relevant to policy debates about climate change. It is hoped that students of both natural and social sciences will use it for the benefit of the Earth’s environments and future societies.

Thomas M. Cronin, Senior Research Geologist, US Geological Survey Reston Virginia