Forty seven years ago, on this day, August 4th, 1978, Science publishes
A Terminal Mesozoic “Greenhouse”: Lessons from the Past
Dewey M. McLean
The late Mesozoic rock and life records implicate short-term (up to 105 to 106 years) global warming resulting from carbon dioxide—induced “greenhouse” conditions in the late Maestrichtian extinctions that terminated the Mesozoic Era. Oxygen isotope data from marine microfossils suggest late Mesozoic climatic cooling into middle Maestrichtian, and warming thereafter into the Cenozoic. Animals adapting to climatic cooling could not adapt to sudden warming. Small calcareous marine organisms would have suffered solution effects of carbon dioxide—enriched waters; animals dependent upon them for food would also have been affected. The widespread terrestrial tropical floras would likely not have reflected effects of a slight climatic warming. In late Mesozoic, the deep oceanic waters may have been triggered into releasing vast amounts of carbon dioxide into the atmosphere in a chain reaction of climatic warming and carbon dioxide expulsion. These conditions may be duplicated by human combustion of the fossil fuels and by forest clearing.
The amount of carbon dioxide in the air was 335ppm. As of 2025, 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 the 1970s was the decade when the basic science became “settled.” For what that turned out to be worth!
The specific context was that by this time the World Meteorological Organisation had said it would hold the First World Climate Conference, in Geneva, in February 1979.
What I think we can learn from this is that information on its own is not worth a bucket of warm spit.
What happened next. The scientists tried to interest the politicians. The politicians didn’t listen. In 1988 the politicians began to pretend to listen. Meanwhile, the emissions just went up and up.
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.
Also on this day:
August 4, 1988 – Hawke Cabinet asks for “what can we do?” report on climate.
August 4, 2004 – Australian farmers nervous about climate change. Ignored – All Our Yesterdays