I was listening to the BBC radio the other day, and there was a discussion with a scientist about how the rising carbon dioxide level in the Earth’s atmosphere was driving global warming. She compared the current mean level of over 400 parts per million to that during the last glacial period, of about 240 ppm, as a contributing factor towards the receding ice caps, and other global warming effects – one of several factors which also included orbital cycles, which could lead to glacial periods. The interviewer asked whether this raised CO2 level was in effect preventing the onset of a new Ice Age. Good question! the scientist seemed to get quite uncomfortable at this point, almost appearing to laugh the question off. Her answer was that we were not able to tell what the future would bring over these kinds of long time periods of 10s of thousands of years.