On this day, July 25, 1933, a Queensland newspaper reports that WJ Chamberlain has given a lecture to students in Melbourne about carbon dioxide in the atmosphere.
The amount of carbon dioxide in the air was 307ppm. As of 2026, when this post was published, it is 430ppm. This matters because the more carbon dioxide in the air, the more heat gets trapped. The more heat, the more extreme weather events. You can make it more complicated than that if you want, but really, it’s not. Fwiw, I have a tattoo of the Keeling Curve on my left forearm.
The broader context was that in the 19th century it had been established that carbonic acid/carbon dioxide acted as a greenhouse gas (by Eunice Foote – though nobody remembered this, and by John Tyndall). In the 1890s Swedish scientist Svante Arrhenius had calculated that a doubling of CO2 would raise temperatures, but thought this would be fine – it would take thousands of years.
The specific context was that although Arrhenius’s calculations had been (wrongly) discounted, the idea was still there.
What I think we can learn from this – the story of carbon dioxide awareness is more complex than we think.
What happened next – Chamberlain took to the airwaves the following month.
On this topic, you might like these other posts on All Our Yesterdays
You can see the chronological list of All Our Yesterdays “on this day” posts here.
What do you think? Does this pass the ‘so what?’ threshold? Have I got facts wrong? Interpretation wrong? Please do comment on this post, unless you are a denialist, obvs.
If you want to get involved, let me know.
If you want to invite me on your podcast, that would boost my ego and probably improve the currently pitiful hit-rate on this site (the two are not-unrelated).
Also on this day:
July 24, 1977 – Climate change as red light? “No, but flashing yellow.”
July 24, 1980 – “Global 2000” report released.
July 24, 2001 – Running from the Storm? Nah, we’re slouching towards it
July 24, 2011 – Rubbery numbers about Gillard’s carbon pricing proposal are disputed…