APS News

Letters

Dyson Debate: Prophet or Heretic?

Freeman Dyson's article, "The Science and Politics of Climate," (The Back Page, May 1999) is both misleading and ill-informed. Dyson begins with the premise that politicians have blindly accepted the predictions of greenhouse gas induced global warming coming out of the general circulation models (GCM) of Manabe and others. Actually, many members of Congress seem to deny the possibility of the greenhouse effect. Some members of Congress have even tried to kill funding for the very observational programs that Dyson esteems.

Dyson goes on to claim that "the public is led to believe that the carbon dioxide problem has a single cause and a single consequence. The single cause is fossil fuel burning, the single consequence is global warming." Does Dyson really think that there is much doubt as to why the levels of atmospheric carbon dioxide have risen from 280 ppm to the present value of about 370 ppm during the span of the industrial revolution? There is an extensive body of data which strongly supports the anthropogenic origin of the increased carbon dioxide. Yes, the carbon cycle is poorly understood, and many things affect the levels of atmospheric carbon dioxide. For example, during warmer years more carbon dioxide is released into the atmosphere from carbon reservoirs and this could be a type of positive feedback which might worsen global warming. But if the public thinks that there is a single cause to the increased levels of carbon dioxide — burning of fossil fuels — they at least have a good first approximation to reality.

Dyson ignores the large body of knowledge known as paleoclimatology. For example, it is easy to make a simple estimate of the consequences of greenhouse-gas forcing on the climate by looking to past ice ages. Also ignored are the results of a number of studies of the past climate over the same timescales as the ATOC project. (Dyson seems to have an axe to grind about the concerns of some marine biologists and environmentalists over the deafening levels of sound produced by the ATOC experiment.) Recent results from the deconvolution of geothermal profile of boreholes, tree-rings and other records indicate that global temperatures had been roughly constant, and perhaps even declined slightly in accord with the astronomical theory of origin of the ice ages, before the advent of the industrial revolution. Strong warming, however, is observed after 1900.

It is certainly true that complicated and incomplete models leave much to be desired. It is also true that even very simple estimates, based on the laws of physics, lead to the same conclusion as most supercomputer models: a doubling of atmospheric carbon dioxide will likely lead to an increase in the average global temperature by several degrees centigrade. Left unsaid is the potential for nasty surprises such as drastic changes in oceanic circulation (which have occurred in the past). This should be the real message of the science and politics of climate: Undesirable warming is likely and the consequences of greenhouse-induced climate change are generally harmful. Do we really want to carry out the global climate experiment to completion?
Brad Marston, Brown University

With regard to Freeman J. Dyson's piece, "The Science and Politics of Climate", one rarely sees such eco-blasphemy in print these days. After all, we all know that catastrophic global-warming caused by man-induced CO2 is an established scientific fact. How do we know? Because the popular media have told us so. But there does exist another, heretical point of view, which almost never sees the light of day. Dyson's piece is part of that heresy. And there are others. If you dig, you can find them. I've assembled a rather large collection of notes I've assembled over the past few years on radical environmentalism in general and specifically on the topic of the CO2/global warming hypothesis. [Editor's note: Readers interested in acquiring Dr. Switalski's list of references may contact him directly at switabern@juno.com.]
Bernard Switalski

Freeman Dyson identifies four coupled reservoirs of carbon, the atmosphere, the ocean, vegetation and soil. He failed to mention the equally important carbon reservoir consisting of the global human population, which is an integral part of the equation. In the absence of any serious scientific study of how to reduce unsustainably large populations, both scientists and politicians seem to be accepting the inevitability of nature's standard methods, famine, disease and holocaust.
Elmer Eisner, Rice University

Wherefore Art Thou, Chandrasekhar?

I saw myself in a photograph on page 5 of the May issue of APS News, identified as being from CSI. My only connection with CSI is that they connect me to the Internet. But thanks to the caption, I am getting a stream of enquiries from friends asking what I am up to now. One wanted to know if I had started an Institute of Superconductivity which I had modestly named after me. I have not, nor do I intend to do so. When asked these days where I am from, I answer, "Groebenzell."
B.S. Chandrasekhar, Groebenzell, Germany




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