Lamb on Ice

14 Jan 2012

HH Lamb on the Ice Age, from chapter 6 of 'Climate History and the Modern World' made some interesting points on the landscape and the fauna illustrated on cave paintings, which as far as Europe was concerned was quite different to what thrived there during the Holocene (since 9500BC). There were mammoths, rhinoceros and horse for example, all mammals that were herbivores and relied on vegetation for sustenance. How much vegetation is a contentious point, and can tie people up in knots - but usually the subject is simply ignored. On page 112 Lamb says early Americans arrived during the Ice Age and an ice free corridor through what is now Alberta had existed. This idea has since been abandoned as far as the Late Glacial Maximum is concerned but as Lamb says on many occasions during the last Ice Age such a route would have existed as the ice sheets were not so extensive - around 30,000 years ago as an example. Now, actual evidence for humans in the Americas as early as that is not on the radar - unless the archaeology jumps out and hits them in the face. 

An aspect of the last Ice Age not commented on as far as Joe Public is concerned is the extent and size of many lakes and inland seas in what is now temperate and lower latitudes, very often arid. This was because rainfall belts were quite different to what they are now. The Caspian Sea for example spread to the NW and N and was twice its modern size, and the same goes for the Aral Sea. In the early 'post glacial' period the Arctic Ocean covered a large area of NW Siberia, and Lamb suggests this was because the land had previously been suppressed by the ice sheet. However, we now know such an ice sheet did not cover Siberia during the Late Glacial Maximum - so, are we talking about a previous manifestation of an ice sheet?

Lake Chad was a huge inland sea and in America lots of lakes lay along the continental divide - now an arid almost rainless zone. Lake Bonneville during the Ice Age was an inland sea as big as the present Aral Sea in central Asia, and Lake Lahontan in NW Nevada was also very large, and two lakes in SE California. In Australai there were lakes where none exist today and it all goes to show a completely different climate regime existed and there is much more to learn about the Ice Ages than science currently would have us believe.