Not Peter James of SIS fame but Peter M James, a geologist from Tasmania, author of 'Extinctions: the Pattern of Global Cataclysm' – and he has an article in the current issue of the NCGT Journal – go to www.ncgt.org/newsletter.php and click on the March issue and then scroll down to page 71-86 for a delightful explanation of a variety of odd phenomena.
At one point he is close to Peter Warlow's polar model of the Late Glacial Maximum, suggesting the North Pole at that time was close to Baffin Island – and Siberia was warmer than it is now. We all know there have been dramatic changes in climate over geological time, and that continental drift is too slow to explain them in many cases. That is why we now have Plate Tectonics.
James throws down the gauntlet immediately. Antarctica is supposed to have been under an ice sheet for the last 15 million years yet fossilised wood has been found in sediments no more than 2 or 3 million years ago (New Scientist, 2nd June 1989). Trees were growing on mountains in Antarctica which suggests it was much warmer on occasion. A change of 40 degrees latitude has been suggested – which means 'drift' occurring 50 times faster than consensus would allow.
At the same time trees were growing in Antarctica it was very cold in Oregon – which may suggest a polar shift is appropriate. In the Late Glacial Maximum, just 20,000 years ago, a polar shift may also have happened – with the pole on or near to Baffin Island. However, he is not suggesting permanent changes at the poles. He is thinking in terms of wobble – leading to polar wandering.
Most people will focus on that part of the article that deals with ancient eclipse data – particularly that of Thucydides. Ancient observations very often do not compare with modern retro-calculations. Even the Chinese record eclipses that do not fit into retro-calculated eclipse paths (and he provides some examples of what he means). The eclipse happened on the dates the Chinese said they did – but not in the geographical zones claimed. Harold Jeffreys of Cambridge claimed a slowing down of Earth's rotation may account for some of the many eclipse that occurred in and at the wrong place – such as one seen at Babylon in 136BC (when retro-calculation places it 4000km to the west and nowhere near Babylon). Unfortunately this would involve lots of slowing down – over and over again (which James thinks unlikely). Deceleration in Earth's rate of spin is not a recognised mechanism. We are dealing with something outside what is regarded as normal behaviour from the Earth. James says the concept of wobble is attractive – transient increases in wobble to account for alterations to the eclipse path – by a potentially huge amount.
Once the wobble regained normality the eclipse path would come back to keel – as a lot of ancient eclipses can be retro-calculated (including the famous Assyrian eclipse of 763BC). To support this he says the Alexandrian astronomer Hipparchus, around 128BC, found that star positions differed from those made just a century earlier, by Eratosthenes. As such he is credited with the discovery of the precession of the equinoxes – but Hipparchus was quite angry with himself so what had he really found. The latitudes he determined from solar observations, which are unaffected by precession, also differed from those made by Eratosthenes. They also differ from the latitudes of today – some lower, some higher. One example, Hipparchus placed Marseilles, his home town, on the same latitude as Byzantium (modern Istanbul) – which would put the North Pole between 1000 and 15000 km from its present location. Modern astronomers assume Hipparchus and Eratosthenes were making faulty observations – but is this really likely as Hipparchus was the most celebrated observational astronomer in the history of Alexandria (and Eratosthenes was no slouch either).
James then brings in Copernicus – and precession of the equinoxes. A century later Newton attributed this to the differential pull of the Sun and the Moon on Earth's equatorial bulge. However, Copernicus also identified stages in the rate of that precession, saying that between the time of Eratosthenes (3rd century BC) and Ptolemy (2nd century AD) the rate of precession was 30 per cent slower than from Ptolemy to the 16th century. The problem of course is that there has been no change or wobble in modern times that scientists can measure.
However, there is a lot more to the article. Wobble would also affect distribution of the world's ocean water. Is this the clue to changes in sea level, he asks – and we might add, might it explain the sea level curve as outlined by Steve Mitchell in his major article published by SIS (in the Late Roman – early A/S period). Polar wander would cause water to amass at equatorial locations – driving away from the new polar regions. James uses sediment cores via bore holes to present his case, and submarine canyons and valleys. The arguments involved are somewhat complex – and speculative (but well worth reading). We have a situation in the recent past where sea levels are known to have changed. They were different even in the medieval period, for example, and the coast during the Roman period appears to be unlike what it is now. It is not that long ago that the Scillies were a large single island – nowadays only the tops of the hills remain above the tide. Most of what had been the farms of Neolithic people is now under the waves. However, it is not as simple as that as a model has been developed to show that sea levels change constantly, going up and coming down – and no real explanation for the phenomenon has as yet emerged – or an explanation that everyone can accept. James may have found why the ocean basins seem to have realigned their water level on numerous occasions during the past. Not to be sniffed at.
James intends to submit a more in-depth article on 'global cataclysms' and in this will also approach the problem of extinction events. I feel this is an important step forwards for the concept of neo-catastrophism and a wobble is perhaps the best way to view the totality of the Younger Dryas event (but not it's inception). In other words, placing all your geese and their eggs in the basket of a wobble is probably a step too far – but as a factor running invisibly in the background, the concept of periodic wobbles seems a reasonable notion. All we need to know now is what causes the wobbles to occur – and planetary influences may pertain, in a regular and predictable cycle. If the Younger Dryas event began with a cosmic encounter, a meteor storm for example, could that have the energy, bearing in mind geomagnetic affects that are fairly modern in concept, to put the Earth into a wobble mode. Whatever, James appears to vindicate Dodwell's attempt to find the curve of a wobble he was sure he had detected, attempting to trace it back to source. However, if wobbles were more common than we might imagine, Dodwell's curve might be superfluous – and impossible to do over a long period of time. Bear in mind that James is talking about transient events – wobbles over short periods of time (yet with repercussions for climate and sea level).