The Discovery of Anthropogenic Global Warming by M. I. Budyko and Wallace Smith Broecker in the 1970s: a Comparative Analysis

In this thesis, I inquire how and why scientists came to realize a new climatic phenomenon – the global temperatures warming trend associated with human activity. Searching for an explanation, I turned to the works of two leading climatologists of the USSR and the USA. The two states are recognized to have carried out the largest number of authoritative studies during the formative period of climate science. The history of climate science as an independent scientific field can be traced back to the late 1950s. The temporal frame of history of this field of science being considered extends up to the 21st century. However, the focus of my consideration is the decade of 1970s, when the concern of scientists over the next ice age gave way to the new pieces of evidence of global temperature warming. The US’ oceanographer and geochemist W.S. Broecker (1931-2019) and the Soviet geophysicist M.I.Budyko (1920-2001) projected advancement of the long-term warming associated with human activity for the first time, in English and Russian language respectively. It would be just to question why I mention two instead of one pioneer. Both scientists in their projection of anthropogenic warming relied on the theory of the Earth's energy balance, proposed by Budyko in the 1950s. As for the 1970s, it was widely used by the climate scientists of both countries. However, theories of anthropogenic warming of Broecker and Budyko had a different source base and relied on different methods. In Budyko's case, instrumental temperature statistics and measurements of atmospheric CO2 concentration were used to project (1972) the future warming triggered by an excess of carbon emissions. While Brocker himself developed a method of radiocarbon dating to attain the data. He projected future warming (1975) based on the paleodata of the Greenland ice cores that were put into a computer model. Although from a formal perspective the hypothesis of anthropogenic warming was earlier proposed by Budyko, in terms of quality of a model, projection of Broecker was more authoritative. While Soviet science held leadership in climate research in its early years, appeared in the late 1960s and spread in the West towards the late 1970s thrown back the research made by scientists in the USSR with no access to supercomputers. The latter allowed to compose complex multi-dimensional computer models that embraced several factors influencing climate and to test them. With the spread of computer modeling, the simple models developed by Soviet scientists began to lose reliability in the eyes of Western scientists and often met certain skepticism. Taking examination of the historical context of the scientists’ research and the impact of their ‘discovery’ on society and politics, I took into consideration the ‘Cold War factor’. As follows from literature and sources, the confrontation between the two powers has shaped the demand for climate research. The possibility of deliberate climate change might be carried out for military or economic purposes. However the plans for geoengineering were not implemented, the very possibility of strategic application of the results of climate research for decades stimulated financial and administrative support of climate research by the governments. On the other hand, the intuitive assumption of an Iron Curtain to be impeding knowledge exchange between Soviet and American climatologists was not proved. Of course, certain limitations on freedom of movement and communication of certain kinds of information were the elements of the historical reality of that time. But, as evidenced by the sources (1. Scientific publications of the scientists, 2. Interview of Budyko and Broecker, 3. An Assessment of the state of climate science in the former Soviet Union prepared by scientists from the US, 4. Scientific correspondence collected by the CIA), the exchange of knowledge between the US and Soviet scientists, and even cooperation on climate change research took place. From this follows that the suggestion of the Cold War being a factor in the lack of communication between scientists of the US and USSR and a precondition for the "double" discovery of anthropogenic global warming is not a correct one