Because of the holiday, our Wednesday environment blog will appear today.
During my daily 4-mile walk, I had an “Aha!” moment listening to 2 Great Courses lectures on the environment. Talking about the “Ruddiman Hypothesis,” Wake Forest’s Robert Whaple said maybe climate change started long before the industrial revolution.
And that took me to William F. Ruddiman’s Columbo moment.
In his book, Plows, Plagues and Petroleum, Dr. Ruddiman said the evidence for the onset of global warming is “deceptive.” If we were to look at a typical graph, the lines for carbon dioxide (CO2) and methane (CH4) start to ascend rather dramatically around 1850 or so. Logically, people connected the rise with the industrial revolution. Ruddiman, a University of Virginia professor emeritus, says that so obvious an incline obscures what had been happening for the previous 8,000 years for CO2 and 5,000 years for methane. And that was his Columbo moment. Reminding us that Columbo was a TV police detective who, when leaving a crime scene, would stop suddenly and say, “Wait a moment,” Dr. Ruddiman did the same with his graph.
Looking back thousands of years, Dr. Ruddiman saw evidence of CO2 and methane accumulation just when scholarly research indicated they should have been dropping. His mind boggling graph indicates a pre-industrial build-up of greenhouse gases that could equal one-third of the current total. Combine deforestation from the onset of agriculture with the widespread creation of rice paddies and irrigation networks and you get a reversal of predicted (GHG) gas trends preceding the 1850s rise.
From explaining why he believed humans had been affecting global warming for multiple millennia, he went on to hypothesize that the earth’s normal cooling and warming cycles have been affected. New ice sheets that would have begun to form, even covering parts of Canada, did not materialize. In other words, thousands of years of global warming forestalled an ice age that we might have experienced.
Dr. Ruddiman very wisely says his research could be used in 2 ways. Global warming skeptics could say that global warming has been beneficial. Others could express alarm that if people with little technology had so great an impact, what are we doing now?
Why an “Aha!” moment? I have concluded that climate science is rather like macroeconomics. You are dealing with innumerable variables, millions of people, and the past, present and future. Just like macro, it is tough to prove even the best theories and just like macro, people have passionate opinions.
Sources and Resources: Dr. Whaples’s lectures #16 and #17 on the environment in his “Modern Economic Issues” course are thought-provoking and chock full of ideas and research references. They led me to the Ruddiman Scientific American article, and to the online first chapter of his book. I also recommend an Econtalk discussion with Judith Curry where Russ Roberts suggested the similarity between climate science and macroeconomics.