Stuart Gaffin is a climate researcher at Columbia University and a regular contributor with his blog “Exhausted Earth”. Thomson Reuters is not responsible for the content - the views are the author’s alone.
Understanding the ice age cycles that have occurred on the Earth during the past million years is — without question — one of the great scientific puzzles of all time.
By ‘great’ I mean not only the importance for many current environmental issues, like climate change and the massive greenhouse gas increases, but great in the sense that solving the mysteries of their occurrence requires breakthroughs from so many different fields of science.
I did post-graduate research on ice ages with a climatologist, Barry Saltzman, who was a co-discoverer of chaos (with Ed Lorenz) and who spent much of his later career on ice age science. I remember marveling with him over the almost ridiculous number of disciplines ice-age science involves: geology, glaciology, climatology, atmospheric physics and chemistry, oceanography, astronomy, geochemistry, biology, geomagnetism, meteorology, nonlinear mathematics and probably other fields I’m not listing!
It’s like we are riding on the back of some kind of Moby Dick of science, learning incredible things about the Earth along the way. Not only that, but the ice ages obviously have shaped us as a species as well since we evolved during the waxing and waning of the enormous ice sheets, influencing our harnessing of technologies (tools, clothing, shelter) and minds. Children are intrinsically fascinated by the ice ages and scientists have been attacking the problem since 1800.
Against this venerable background, I am humbly publishing a paper that tries to paint a new picture of the ice ages. I am linking it here (and publisher here) for those of you want to see the details of my case.
There is a more-or-less standard model of the recent ice ages that says they have resulted from a gradual long-term cooling of the Earth since the time of the dinosaurs, when no glaciers are known, towards the present. At some point, around 34 million years ago, the Earth became cool enough for large scale glaciers to form on Antarctica and later elsewhere, culminating in the great 100-thousand year cycles that have dominated recent times.
My paper does not question this model — indeed it is essential for my case that it is largely correct. Rather I focus on the 100-thousand year cycle mystery and what caused that. The essence of my paper is that this mystery of the cycles may be related to another cycle in geology that is also unexplained – sedimentary cycles on the margins of continents during warm geologic epochs.
These coastal cycles were discovered by oil geologists (most notably at Exxon) during the 1960s and 1970s. In my paper I try to show that there are a mind-bending number of parallels between these two cycles that cannot be accidental. The one common link that explains these parallels is that both ice sheets and continental margin systems are sedimentary systems.
You can read my paper if interested but among other things I conclude that continental margin sediments may oscillate almost automatically. Another conclusion, relevant to current global warming, is that my paper bolsters the case that Antarctica did not support any glaciation during very high greenhouse gas periods of geologic history. I think we are just at the ‘tip of the iceberg’ in understanding the mysteries of ice ages and their relation to other systems on Earth.
The leviathan lives on!
(Credits: top right: an image of Cro Magnon Man, Photo by Roderick Mickens, copyright by American Museum of Natural History. Map centre: Ice sheet extent during ice age: Hannes Grobe/AWI)
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