On this day seventy five years ago at an American Association for the Advancement of Science symposium the famed biologist Evelyn Hutchinson mentioned carbon dioxide buildup as something to be aware of, in his pivotal article Circular Causal Systems in Ecology:
The problem of the constancy or variability of the carbon dioxide content of the atmosphere as a whole is a difficult one, owing to the large number of possible sources of purely local disturbance. The earlier data have been reviewed by Letts and Blake (1900) and, more recently, practically all the available information has been considered by Callendar (1940). … Meanwhile, it seems far more likely that the observed increment in the carbon dioxide of air at low levels in both Europe and eastern North America is due to changes in the biological mechanisms of the cycle rather than to an increase in industrial [[p. 228]] output. It is quite probable that the net effect of the spread of the technological cultures of the North Atlantic basin has been to decrease the photosynthetic efficiency of the land surfaces of the earth.
The amount of carbon dioxide in the air was roughly 310ppm. As of 2023 it is 423ppm, but check here for daily measures.
The context was that English steam engineer Guy Callendar had been collating what carbon dioxide measurements existed, and said they were going up, in line with Svante Arrhenius’s late 19th century suggestion. But all this was very sketchy – precise measures were not yet a thing.
What we can learn – the biologists and ecologists (stocks and flows, flows and stocks) were paying attention.
What happened next – Evelyn Hutchinson mentioned it in a big 1955 US conference about resources and conservation – crickets. He also mentioned it to King Hubbert (him of the Peak) and so it ended up in Hubbert’s Energy Resources report in 1962…