Session 1: Development of the hypothesis
Session 2: Challenges to the hypothesis
Session 3: interview: Nick Christie-Blick, L-DEO
You have just written about what constitutes excellent science? According to the criteria of your fall semester term paper, is the Snowball Earth idea excellent science?
Are there any parallels in the controversy between Snowball earth and the K/T Extinction?
Would you consider Snowball Earth a theory or a hypothesis? Compare to how the popular press presents Snowball Earth.
Do you detect any bias in the press? If so, where?
How skeptical has the press been about accepting Snowball Earth?
Do you think the press has reported Snowball Earth accurately?
During Snowball Earth, would the snow have been good for making a snowman or was it that light, fluffy snow that doesn’t stick?
How have journalists tried to make this esoteric Snowball Earth idea pertinent to modern human beings.
What pieces of what we now call Snowball Earth hypothesis were known prior to Hoffman & Schrag 1998 paper? What was the contribution of Hoffman & Schrag 1998?
1989 Los Angeles Times by Thomas Maugh II. This article predates any other popular article that I have been able to find on Snowball Earth by more than six years. How do you suppose he did this? And how good a job did he do under the circumstances?
We have four articles following up immediately (within a week) on the Hoffman and Schrag 28 Aug 1998 Science paper: New York Times (William K. Stevens), Robert Boyd for Knight-Ridder Tribune News; BBC, and Science News (Richard Montastersky). Compare and contrast the four.
The next two articles, in Smithsonian and New Scientist, came out about a year and a half after the Hoffman and Schrag 1998 Science paper, giving far more time for reporting and reflection than in the previous four pieces. Did the year-later magazine journalists do better than within-a-week newspaper journalists, and if so, how?
Dec 1999, Smithsonian. What point did Trefil overlook or misunderstand?
In Hoffman & Schrag's 2002 review paper in Terra Nova (p. 135), they cite an LA Times article by Tom Maugh as Kirschivink's first exposition of the Snowball Earth hypothesis. Why did they do this? Did Kirschivink and colleagues make a mistake by allowing their results to appear in such detail in the popular press so long before their papers were published?
We have four pieces reporting on the computer modelling of Hyde et al 2000 (with or without the computer modelling of Chandler et al 2000): Discovery Channel, Dick Kerr in Science, Curt Suplee in Washington Post, BBC News, P.Weiss in Science News. Which does the best job of conveying the process of using a computer model to test a geoscience hypothesis?
P. Weiss (of the post-Hyde articles) casts Hyde's results as an "alternative to the snowball theory's ice-engulfed planet" whereas Curt Suplee casts Hyde's results as "Some doubts about the snowball hypothesis may have been alliviated." How would you characterize the relationship between Hyde's modelling and H&S's theory.
22 March 2001, transcript of Earth and Sky radio show. Is such a short piece on such a complicated subject useful?
8 Mar 2002, transcript of Horizon program on BBC. What has this long video format allowed the BBC to do that media weren't able to do?
What strategies have journalists used to cover challenges to the Snowball idea?
Hoffman, Paul F. and Schrag, Daniel P., Snowball Earth, Scientific American, January 2000, pp 68-75.
Hoffman, Paul F. and Maloof, Adam C., Tilting at snowballs, Department of Earth and Planetary Sciences, Harvard University, Cambridge, MA, January 30, 2001.
Budyko, M. I., The effect of solar radiation variations on the climate of Earth, Tellus (21), 1969, 611-619.
Kirschivink, Joseph L., Late Proterozoic low-latitude global glaciation: the snowball Earth, In J. W. Schopf and C. Klein, eds., The Proterozoic Biosphere: A multidisciplinary study, Cambridge University Press, Cambridge NY, 1992, pp. 51-52.
Kennedy, M. J., Stratigraphy, sedimentology, and isotopic geochemistry of Australian neoproterozoic postglacial cap dolostones: Deglaciation, d13____________, and carbonate precipitation, Journal of Sedimentary Research, 66(6), 1996, pp. 1050-1064.
Evans, D. A., Beukes, N. J. and Kirschvink, J. L., Low-latitude glaciation in the Palaeoproteroic era, Nature, 386, March 20, 1997, pp. 262-266.
Kaufman, Alan J., An ice age in the tropics, Nature 386, March 20, 1997, pp. 227-228.
Hoffman, Paul F., Kaufman, Alan J., Halverson, Galen P., and Schrag, Daniel P., A neoproterozoic snowball earth, Science, August 28, 1998, pp. 1342-1346.
Comments on above article:
Maugh, Thomas, H. II, ‘Completely Different’ evolution idea super ice age gave life on earth growing pains series: In the beginning. The search for the origins of life. Second in a series, Los Angeles Times, September 7, 1989.
Tindol, Robert, Caltech scientists find evidence for massive ice age when earth was 2.4 billion years old, Cal tech Press Release, March 19, 1997.
Stevens, William K., Tracks of ancient ice lead to a picture of "Snowball Earth", N. Y. Times, March 25, 1997.
Anonymous, Snowball Earth, Discover, July 1997, p. 24.
Boyd, Robert S., Scientific evidence shows earth once was a big snowball, Houston Chronicle, Aug. 27, 1998.
Anonymous, Sci/Tech Earth’s hue ‘snowball event’, BBC News, August 28, 1998.
Monastersky, Richard, Popsicle Planet: The king of all ice ages may have spurred animal evolution, Science News, 154, Aug. 29, 1998, pp. 137-139.
Stevens, William, A Theory: Too cold, too hot, then just right for animals, New York Times, Sept. 1, 1998, Page 4, Col. 1, Section F.
Walker, Gabrielle, Snowball Earth, New Scientist, Nov. 6, 1999, 28-33.
Trefil, James, When the earth froze, Smithsonian Magazine, December 1999.
Kirschvink, Joseph L. Gaidos, Eric, J., Bertani, L. Elizabeth, Beukes, Nicholas, J., Gutzmer, Jens, Maepa, Linda N., and Steinberger, Rachel E., Paleoproterozoic snowball Earth: Extreme climatic and geochemical global change and its biological consequences, Proceedings of the National Academy of Science, 97 (4), Feb. 15, 2000, pp. 1400-1405.
Tindol, Robert, Snowball Earth episode 2.4 billion years ago was hard on life,
good for modern industrial economy, research show, Cal tech Press Release, Feb. 14, 2000.
Reed, Christina, Freeze-fry from the snowball earth, Geotimes, Feb. 2000.
Hyde, William T., Crowley, Thomas, J., Baum, Steven K., Peltier, W. Richard, Neoproterozoic ‘snowball Earth’ simulations with a coupled climate/ice-sheet model, Nature (405) May 25, 2000, pp. 425-429.
Kennedy, Martin J., Christie-Blick, Nicholas, Sohl, Linda E., Are Proterozoic cap carbonates and isotopic excursions a record of gas hydrate destabilization following Earth’s coldest intervals?, Geology, 29 (5), May 2001, pp. 443-446.
Comment & Reply
Hoffman,. Paul F., Halverson, Galen, P., Grotzinger, John P., Are Proterozoic cap carbonates and isotopic excursions a record of gas hydrate destabilization following Earth’s coldest intervals?: Comment, Geology, March 2002, pp. 286-287.
Kennedy, Martin J., Christie-Blick, Nicholas, Sohl, Linda E., Are Proterozoic cap carbonates and isotopic excursions a record of gas hydrate destabilization following Earth’s coldest intervals? Reply, Geology, March 2002, pp. 287-288.
Shapiro, Russell S., Are Proterozoic cap carbonates and isotopic excursions a record of gas hydrate destabilization following Earth’s coldest intervals? Comment, Geology, August 2002, pp. 761-762.
Max, M. D. and Dillon, W. P., Comment, Geology, August 2002, pp. 761-762.
Kennedy, Martin J., Christie-Blick, Nicholas, Sohl, Linda E., Are Proterozoic cap carbonates and isotopic excursions a record of gas hydrate destabilization following Earth’s coldest intervals? Reply, Geology, August 2002, 763.
Kennedy, Martin J., Christie-Blick, Nicholas, Prave, Anthony R., Carbon isotopic composition of Neoproterozoic glacial carbonates as a test of paleoceanographic models of snowball earth phenomena, Geology, 29(12), Dec. 2001, pp. 1135-1138.
Condon, D. J. , Prave A. R., Bean, D. I., Neoproterozoic glacial-rainout intervals: Observations and implications, Geology, 30 (1), Jan. 2002, pp. 35-38.
Hoffman, Paul F. and Schrag, Daniel P., The snowball earth hypothesis: testing the limits of global change, Terra Nova, 14, 2002, pp. 129-155.
Cowing, Keith, Snowball Earth may not have been that bad after all, Discovery Channel, May 26, 2000.
Kerr, Richard A., A Refuge for Life on Snowball Earth, Science, May 26, 2000, pp. 1316.
Suplee, Curt, ‘Big Chill’ Theory Starts to Snowball, Washington Post, May 29, 2000.
Anonymous, How life survived the big freeze, BBC News, May 25, 2000.
Weiss, P., Warm band may have girdled snowball Earth, Science News, 157, May 27, 2000, p. 343.
Kerr, Richard A., An appealing snowball Earth that’s still hard to swallow, Science, 287, March 10, 2000, pp. 1734-1736.
Anonymous, ‘Snowball Earth’, BBC News, February 22, 2001.
Portree, David S. F., Snowball Earth, Earth & Sky, March 22, 2001.
Hecht, Jeff, Cold shoulder for global snowball, New Scientist, June 9, 2001, p. 12.
Chandler, David L., Snowball Earth grapples with a puzzling new theory: The extreme ice age, Boston Globe, June 12, 2001.
Chang, Kenneth, Scientists Try to Explain the Cold, Mysterious Era of ‘Snowball Earth’, New York Times, June 19, 2001.
Kerr, Richard A., Of ozone, teapots, and snowballs, Science, 292, June 22, 2001, pp. 2241 & 2243.
Simpson, Sarah, Triggering a snowball: Did methane addiction set off Earth’s greatest ice age? Scientific American.Com, Sept. 16, 2001.
Kerr, Richard A., A not so comatose snowball, Science, December 7, 2001.
Adler, Robert, Meltin away: The “Snowball Earth” idea is starting to fell the heat, New Scientist, Dec. 15, 2001, p. 15.
Highfield, Roger, Earth: the biggest snowball fight. Daily Telegraph, Dec. 19, 2001,
Lubick, Naomi, Snowball fights, Nature, 417 (6884), 2002, p. 12-13.
Anonymous, ‘Snowball Earth’ theory melted, BBC News, March 6, 2002.
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