In 1997, Milanković, Not Greenhouse, Was the De Facto Theory of Climate Change

In 1997, the environmental publication Ambio—a peer-reviewed journal on behalf of the Royal Swedish Academy of Science—would publish a special edition “commemorating the 100-year anniversary of the publication of Svante Arrhenius’ landmark paper on the greenhouse effect.” Arrhenius is considered the godfather of climate change, being the first scientist to detail connections between carbon dioxide in the atmosphere and temperature change.

While the paper that introduced the special edition would go on to detail many of Arrhenius’ accomplishments, it would also note that the established understanding of climate had changed significantly since his work was published in the late 1800s.

Rather than carbon dioxide causing increases in temperature, variations in the Earth’s orbit and angle of the sun were causing changes in temperature—otherwise known as the Milanković theory after Serbian scientist Milutin Milanković—which is leading to changes in CO₂:

However, the variation in CO₂ is believed to be driven by, and at the same time to amplify, the temperature changes primarily caused by variations in the Earth’s orbit around the sun (the “Milanković theory.” It is not known how the temperature variations influenced the CO₂ concentrations during the glacial cycles, although feedback processes involving the oceans and/or the terrestrial biosphere must have been involved. While the glacial-interglacial temperature variation is not believed to be primarily caused by variations in the CO₂ concentration (driven by volcanic activity), as Arrhenius suggested, it has been deduced that a substantial fraction of the amplitude in the glacial temperature cycle may be due to the changes in CO2 as part of the carbon cycle in the coupled atmosphere/ocean/biosphere system.

The paper cites another paper by André Berger and Marie-France Loutre, Paleoclimate Sensitivity to CO₂ and Insolation, also published by the Royal Swedish Academy of Sciences. That paper gets into much more intimate detail as to how astronomical parameters, like the Earth’s orbit around the sun, affects insolation—solar radiation that affects the Earth—and how that affects CO₂ levels and water vapor in the atmosphere.

The authors’ bonafides are numerous. Berger has been honorary President of the European Geosciences Union, fellow of the American Geophysical Union, and chairman of both the International Climate and the Paleoclimate Commissions and President of the European Geophysical Society.

The authors of the Ambio paper on Arrhenius includes Henning Rodhe, professor emeritus of chemical meteorology at Stockholm University and Robert Charlson, a professor emeritus of atmospheric sciences, chemistry, and geophysics at the University of Washington who helped define the CLAW hypothesis of climate cycles.

Since 1997, climate science has changed significantly. In 1998, Michael Mann would publish his model supposedly showing carbon dioxide and other greenhouse gases as a predictor of temperature, not the other way around. That research would be used in a populist campaign that painted human-caused climate change as the number one priority of government policy out of fear of global environmental collapse.

The Intergovernmental Panel on Climate Change (IPCC), something Rodhe had been a lead author on papers for, has since put its sole focus on anthropogenic warming—human-caused global warming through the release of greenhouse gases like carbon dioxide and methane.