Michael Towsey, Tasmania, Australia
Dear Editor,
Congratulations on your second edition of Neohumanist Review that featured articles about climate change. Concerning the article “Climate Change – from the deep past to the 22nd century”, I wrote it in August/September of 2023. Climate change science is a rapidly evolving field with new research papers appearing every month. I would like to alert your readers to a couple of updates.
First, it was probably foolish of me to cite the Fairbridge paper from as far back as 1987 to argue that the so-called “snowball earth” episode never happened. In the intervening 37 years, the evidence for ice-cover extending to the equator for an extended period is now very strong. The Wikipedia page “Snowball Earth” (en.wikipedia.org/wiki/Snowball_Earth) provides an excellent summary of the evidence for and against snowball earth. And I strongly recommend the 2023 BBC 2 documentary series Earth for fascinating insights into the Earth’s ancient ice-ages and climate.
Second, I made the comment: “There is no evidence that fluctuations or reversals of the Earth’s magnetic field have had any effect on climate or biological evolution over geological time scales.” True—until recently! A recent research paper (Cooper et al., 2021) claims that a geomagnetic field event 42,000 years ago “caused substantial changes in atmospheric ozone concentration and circulation, driving synchronous global climate shifts that caused major environmental changes, extinction events, and transformations in the archaeological record”. What makes the timing so interesting is that 42,000 years ago coincided with the extinction of the Neanderthals and the rapid emergence of modern humans. It is also interesting that Sarkar (1986) states that geomagnetic phenomena will play an important role in future climate change events. But these ideas remain controversial. So watch this space!
This article will be updated periodically to accommodate new discoveries. It can be accessed at theneohumanist.com/2023/10/23/climate-change-from-the-deep-past-to-the-22nd-century/.
References
Cooper, A., Turney, C., et al., (2021) A global environmental crisis 42,000 years ago, Science V371, pp811–818, 19 February 2021. science.org
Sarkar, P.R. (1986) The Poles Shift Their Respective Positions, published in: A Few Problems Solved Part 7, Calcutta.