I read the Australians' report of your address to primary school students in my home state. I read the brief report with significant and mounting disquiet. You, sir are in a position of considerable authority, and are the potential leader of this country. Thus, when you talk to primary school students it is very important that you get your statements and logic right.
"OK, so the climate has changed over the eons and we know from history, at the time of Julius Caesar and Jesus of Nazareth the climate was considerably warmer than it is now,"No, no it wasn't. All the reliable reconstructions show that the climate that far back was cooler than now (see the graph above, and here and here). All the evidence shows that the warming in the last 25-30 years is unprecedented in the past two millennia. You also said:
"And then during what they called the Dark Ages it was colder. "No, no it wasn't (see above). You also said:
"Climate change happens all the time and it is not man that drives those climate changes back in history."Which is irrelevant to the issue of whether humans are causing climate change now. Back in Medieval times humans weren't pumping vast quantities of greenhouse gasses into the atmosphere. As a simple matter of logic, the fact that humans have not produced global climate change in the past does not mean we cannot do it now. After all, humans didn't produce any changes in the ozone layer in the past, yet our activities created the Ozone Hole. You said:
"It is an open question how much the climate changes today and what role man plays."Not true, in the sense you are implying. We are committed to a warming world, whether we get 2 degrees or 7 degrees warmer by 2100 depends on how much we mitigate our greenhouse gas emissions. Currently, several of our warming indicators are tracking near the worst case scenario predictions, which is quite disturbing. It is also quite clear that human greenhouse gas emissions are the culprit behind most of this warming (see The Copenhagen Diagnosis for a simple and clear explanation). This is simple physics, you put in more greenhouse gasses, the world warms. The children you were speaking to could demonstrate this themselves with a simple experimental apparatus.
You may not be impressed by foreign academies, but surely, as a possible future Prime Minster, you should not ignore the advice of the CSIRO that the world is warming, with humans largely responsible. The CSIRO is after all Australia's most respected scientific institution, to which the government goes for scientific advice. If you cannot accept the advice of this institution, what does this bode for your acceptance of advice on other issues that turn on scientific evidence.
Mr Abbott, those children you spoke to are our future, as well as the ones who will be left with the legacy of our inaction of global warming. You, as a potential Prime Minister have a special duty not mislead these same children with incorrect statements and poor logic.
Yours sincerely, Ian Musgrave
EDIT: The The Roman Warm Period really did exist, but was not a global event, rather a largely European/North Atlantic one, based at least on changed ocean currents (see for example Earth and Planetary Science Letters Volume 213, Issues 1-2, 1 August 2003, Pages 63-78). And the most recent evidence is that it was not warmer than the medieval warm period (GEOPHYSICAL RESEARCH LETTERS, VOL. 33, L20703, doi:10.1029/2006GL027662, 2006) except perhaps in isolated spots. So Mr. Abbott, when you get climate advice, make sure you get it from real climate scientists.
EDIT AGAIN: Tim Lambert traces Mr Abbott's assertions to Ian Plimer. No wonder Mr. Abbott got it wrong.