They show a world population of 255 million in 1 AD which was not to be surpassed for nearly 1,000 years; in fact by 400 AD the population is estimated to have fallen to 206 million & just stayed at that figure for the next 200 years.
This coincides of course with the end of the Roman Empire, & a pretty much Europe-wide collapse in the infrastructure of towns – a fact which was noted in the recent In Our Time 2-part special on The City.
It is also of relevance to the climate change debate, the (in)famous hockey stick graph & the so-called Medieval Warm Period (AD 800 to 1400). I do not know how or if the IPCC took account of historical population change & movement, & I am not in a mood to find out at the moment.
But there is a recent post on Gravity & Levity, The global temperature is inherently unstable, which looks interesting; I have printed of a copy to read since it is not the kind of thing I can take in properly from a screen. But I should like to quote here the authors apology for not joining the debate sooner:
“It has been such an emotionally- and morally-charged debate during the past few years that only very rarely is a fact presented without an accompanying censure or call to arms. This creates a particularly bad environment for the advancement of scientific debate, where dissenters are immediately shouted down because of a strong political/social pressure to reach consensus (not that I can’t see why; there is much more urgency to global warming than to most scientific riddles). The problem is that the fundamental mechanism through which scientific ideas advance is disagreement. If scientists aren’t allowed to argue with each other, then they arrive at the truth much more slowly.”
Those are points which other non-denying sceptics have been making recently, but none with such eloquent heartfelt simplicity
