Chamberlin, Thomas Chrowder

June 5, 2012, 9:25 pm

 

caption Thomas Crowder Chamberlin. (Source: University of Wisconsin–Madison Archives)

 

Thomas Chrowder Chamberlin (1843-1928) was a respected and influential American geologist and science educator who supported the concepts of multiple glaciation and planetesimal origin of the Earth, and was among the first to emphasize carbon dioxide as a major regulator of Earth's temperature.

Chamberlin's dominant interest was glacial geology. Work with the Wisconsin Geological Survey and the USGS in the 1870-80s resulted in accurate mapping of the limits of glaciation in the United States, in basic laws of glacier ice movement, and in recognition of multiple glaciations. These results are contained in two classic monographs of the USGS: Preliminary paper on the terminal moraine of the second glacial epoch (1882) and The rock scorings of the great ice invasions (1886). Chamberlin developed the terminology for glacial stages in North America that is still utilized with some modifications. He first demonstrated that there had been multiple Pleistocene glaciations in North America and was the first director of the U.S. Geological Survey's Pleistocene Division (1881–1904). He presented early analyses of moraines, drumlins, eskers, and boulder trains. From these features, he inferred regional glacial flow patterns, differentiated ice lobes, and mapped the outermost limits of the two last glacial advances. He called glacial striations “trails left by the intruder.”

In 1899, Chamberlin challenged famous physicist Lord Kelvin's calculation of an age for Earth of only 20–30 million years when geologists were thinking of 100 million. Chamberlin disputed Kelvin's assumption of simple cooling from a molten origin because he was already formulating his own cold, planetesimal origin. He argued that there must be some unknown source of heat energy within Earth that would alter Kelvin's calculations substantially. Without realizing it, Chamberlin had anticipated heat from radioactive decay, which had just been recognized but was not yet widely understood.

Chamberlin developed a theory of climate change and was one of the first to emphasize carbon dioxide as a major regulator of Earth's temperature, thus anticipating modern global warming.[1] Chamberlin was the first to demonstrate that the only way to understand climate was to understand almost everything about the planet together — not just the air but the oceans, the volcanoes bringing gases from the deep interior, the chemistry of weathered minerals, and more. Chamberlin hypothesized that that ice ages might follow a self-oscillating cycle driven by feedbacks involving CO2. The gas was originally injected into the atmosphere in spates of volcanic activity. It was steadily withdrawn as it combined with minerals during the weathering of rocks and soil. If the volcanic activity faltered, then as minerals leached the gas out of the atmosphere, the planet would cool. Feedbacks could make a temporary dip spiral into a self-reinforcing decline. For one thing, as the land cooled, bogs and the like would decompose more slowly, which meant they would lock up carbon in frozen peat, further lowering the amount of CO2 in the air. Moreover, as the oceans cooled, they too would take up the gas — warm water evaporates a gas out, cold water absorbs it. The process would stop by itself once ice sheets spread across the land, for there would then be less exposed rock and bogs taking up CO2. Reversing the process could bring a warming cycle.

Chamberlin's speculation about ice ages was one of many at the time, but he had pioneered the modeling of global movements of carbon. He made rough calculations of how much carbon was stored up in rocks, oceans, and organic reservoirs such as forests. He went on to point out that compared with these stockpiles, the atmosphere contained only a minor fraction — and most of that CO2 cycled in and out of the atmosphere every few thousand years. It was a delicate balance, he warned. Climate conditions "congenial to life" might be short-lived on geological time scales.

Chamberlin was president of the Geological Society of America (1894–1895), president of the Wisconsin (1885–1886), Chicago (1897–1915), and Illinois (1907) Academies of Science, president of the American Association for the Advancement of Science (1908–1909), member of the National Academy of Sciences (1903), and the first Penrose Medalist of both the Society of Economic Geologists (1924) and Geological Society of America (1927). He was a member of the American Philosophical Society and the American Academy of Arts and Sciences and received six honorary degrees. In 1909, he spent five months traveling as a member of a commission to determine how the Rockefeller Foundation could best aid China. In 1893 he founded the Journal of Geology, of which he was editor for many years.

Notes

  1. ^ This section is drawn from Weart, Spencer, Simple Models of Climate, The Discovery of Global Warming, American Institute of Physics.

Sources


Further Reading

  • Chamberlin, Thomas C. (1897). "A Group of Hypotheses Bearing on Climatic Changes." J. Geology 5(653-83).
  • Chamberlin, Thomas C. (1898). "The Influence of Great Epochs of Limestone Formation Upon the Constitution of the Atmosphere." J. Geology 6: 609-21.
  • Chamberlin, Thomas C. (1899). "An Attempt to Frame a Working Hypothesis of the Cause of Glacial Periods on an Atmospheric Basis." J. Geology 7: 545-84, 667-85, 751-87.
  • Chamberlin, Thomas C. (1906). "On a Possible Reversal of Deep-Sea Circulation and Its Influence on Geologic Climates." J. Geology 14: 363-73.
  • Chamberlin, Thomas C. (1923). "Study of the Fundamental Problems of Geology." Carnegie Institution Year Book 22: 325, 330-32.
Glossary

Citation

Cleveland, C. (2012). Chamberlin, Thomas Chrowder. Retrieved from http://www.eoearth.org/view/article/151054

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