(SV*)null
interpreting the void as SamV
In my previous post, I laid down terms for a chapter-at-a-time review of Wishart's _Air Con_, on David White's blog post, Climate Change: NZ as a leader? No and Yes!
He seems willing:
This is the most sensible suggestion that I've heard from anyone. And I'm willing to do it. (The hardest part will be to keep to the spirit of the exercise, but I agree with the intent.)
...
Rather than studying a chapter or essay, I'd rather just take turns asking a factual question, and then trying to reach a consensus on the answer. Some questions are IMHO too big or hard to tackle immediately (eg is global warming caused by humans?). I suggest we start with baby steps. Eg Does Earth's climate change?
Well, this is a starting point. The danger of this style of questioning is that it is a common tactic used to frame an argument towards an pre-determined conclusion. Often a question can say more by what it does not say, ie implication.
Does Earth's climate change?
Well, clearly the answer is yes; but the clear implication is that this past variability implies that it might not change in a predictable manner today.
The driving influences to Earth's modern climate are all very well known; in the Holocene, Milankovitch cycles / orbital variations (see also my earlier post on Kukla) and CO₂ levels are dominant influences, affect and reinforce each other's action to cause the cycle we know as the Ice Ages. This is confirmed in great detail - ie, every wiggle of the graph that Astronomy tells us the orbit should have passed through in the last 3 million years - by detailed geological records - especially the 5-million year record from the Wanganui basin, and proxies such as the ice core records. Go back further, and you start looking at a very different planet, with one global ocean and the ice caps over the south pole would periodically melt. At times there were no ice caps at all. Go back 55 million years, and something must have been obviously different because we saw a doubling of CO₂ levels but something like 7°C higher temperatures.