by A. May, Oct 321, 2020 in WUWT
Roger Revelle was an outstanding and famous oceanographer. He met Al Gore, in the late 1960s, when Gore was a student in one of his classes at Harvard University. Revelle was unsure about the eventual impact of human carbon dioxide emissions on climate, but he did show that all carbon dioxide emitted by man would not be absorbed by the oceans. For an interesting discussion of Revelle’s work in this area see this post on “The Discovery of Global Warming,” by Spencer Weart (Weart, 2007). The original paper, on CO2 absorption by the oceans, published in 1957 by Roger Revelle and Hans Suess, is entitled: “Carbon Dioxide Exchange Between Atmosphere and Ocean and the Question of an Increase of Atmospheric CO2, during the Past Decades” (Revelle & Suess, 1957). This meant that human emissions of carbon dioxide would accumulate in the atmosphere and that the CO2 atmospheric concentration would increase, probably causing Earth’s surface to warm at some unknown rate. This is not an alarming conclusion, as Revelle well knew, but Al Gore turned it into one.
One of Revelle’s good friends was Dr. S. Fred Singer. Singer was a professor of environmental science at the University of Virginia and both Revelle and Singer had been science advisors in the U.S. Department of the Interior. They first met in 1957 and were more than professional colleagues, they were personal friends (Singer, 2003). Unfortunately, Revelle passed away in July 1991 and Singer passed away in April 2020, so we will refer to them and their friendship in the past tense. Both were leading Earth scientists and at the top of their fields, it was natural they would become friends. They also shared an interest in climate change and chose to write an article together near the end of Revelle’s life.
Indeed, ten years later, CO2 emissions were still increasing, but the world had started to cool as shown in Figure 1. This casts considerable doubt on the idea that human emissions somehow control global warming, since some other factor, presumably natural, is strong enough to reverse the overall warming trend for ten years. Revelle was correct to encourage the government to wait for ten more years. Just a year before their paper was published the IPCC reported that warming to date fell within the range of “natural variability” and that the detection of a human influence on climate was “not likely for a decade or more.” (IPCC, 1990, p. XII).
Figure 1. In 1990 and 1991, respectively, the IPCC and Roger Revelle and colleagues said it was too early to do anything about possible man-made climate change, they thought we would know more in 10 years. The plot is smoothed with a 5-year running average to reduce the effect of El Nino and La Nina events. This makes the longer term trends easier to see.