Plate tectonics “holds lessons for today’s debates about human-induced climate change”
DOI: 10.1063/PT.5.8004
Observers of climate-science politics know scientist and historian Naomi Oreskes as—just to give one example—the coauthor of Merchants of Doubt: How a Handful of Scientists Obscured the Truth on Issues from Tobacco Smoke to Global Warming . In a new commentary in Nature, she defends the validity and integrity of scientists’ climate consensus by likening its evolution to that of the consensus on plate tectonics more a half century ago.
A “slow convergence of ideas and evidence,” she explains, is seen in the history of plate tectonics, geologists’ theory of Earth’s outermost shell. She argues, “Although science is always evolving, and our attention is drawn to controversy at the research frontier, it is the stable core of ‘consensus’ knowledge that provides the best basis for decision-making.”
Oreskes recently moved from the University of California, San Diego, to Harvard, where her web page reports that her “research focuses on the earth and environmental sciences, with a particular interest in understanding scientific consensus and dissent.” Her Nature essay traces the decades-long progress and convergence of scientific understanding involving paleontological connections between separated land masses, “stripes of alternating magnetic-field polarity in ocean bedrock as evidence of a spreading sea floor that pushed continents apart,” continent-scale crustal motion, and geomagnetic findings that stemmed in part from Cold War naval study of submarines’ environment.
“It was one thing to say that the oceans were widening,” Oreskes observes, and “another to link it to global crustal motion. More than two dozen scientists, including women such as Tanya Atwater and Marie Tharp, did the key work that created the theory of plate tectonics as we know it—explaining continental drift, volcanism, seismicity and heat flow around the globe.”
Oreskes emphasizes that this evolution of scientific knowledge stemmed from collective effort leading to expert agreement. She posits that many “who disparage the scientific evidence of anthropogenic climate change” find expert agreement “irrelevant.” She declares that many critics advocate the “mythology” of the lone genius, tapping “into a rich cultural vein” but missing “what consensus in science really is and why it matters.” She continues:
Consensus emerges as scientific knowledge matures and stabilizes. With some notable exceptions, scientists do not consciously try to achieve consensus. They work to develop plausible hypotheses and collect pertinent data, which are debated at conferences, at workshops and in peer-reviewed literature. If experts judge the evidence to be sufficient, and its explanation coherent, they may consider the matter settled. If not, they keep working. History enables us to judge whether scientific claims are still in flux and likely to change, or are stable, and provide a reasonable basis for action.
In summing up, Oreskes invokes the memory of Harold Jeffreys, an astronomer who rejected plate tectonics. “His view had a strong mathematical basis,” she stipulates, “but it remained unchanged, even as evidence to the contrary mounted.” Her final paragraph offers a prediction:
Fifty years on, history has not vindicated Jeffreys, and it seems unlikely that it will vindicate those who reject the overwhelming evidence of anthropogenic climate change.
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Steven T. Corneliussen, a media analyst for the American Institute of Physics, monitors three national newspapers, the weeklies Nature and Science, and occasionally other publications. He has published op-eds in the Washington Post and other newspapers, has written for NASA’s history program, and is a science writer at a particle-accelerator laboratory.