Scientists, politicians and public policy

In the light of these findings, Dr Stockwell suggests to the authors that “Studies of complex variables like droughts should be conducted with statisticians to ensure the protocol meets the objectives of the study”, and offers some examples of how known statistical methods might be used to improve drought projections. More generally, Stockwell concludes that “Policy making based on science should not be influenced by studies that appear scientific but do not adhere to the generally accepted validation practices”.

Dr Stockwell’s critique of the CSIRO/Bureau of Meteorology report does not constitute a rejection of the need for the application of the scientific method in climate science modelling. On the contrary, his analysis is in itself an affirmation of the need for a rigorously scientific approach in this area - and his successful efforts to bring about the publication of all supporting information will not only facilitate the external scrutiny of the Drought Exceptional Circumstances Report that its importance demands, but will also enable other experts to seek to reproduce Stockwell’s analysis. This can only lead to more enlightened public policy.

It should be stressed that Dr Stockwell’s study does not demonstrate that droughts in Australia will not become more frequent and/or more severe. But if his analysis withstands expert scrutiny he will have shown that the report on future drought events by Australia’s two leading climate science research bodies does not meet basic tests of climate model validity and cannot serve as a guide to policy.

It is truly unfortunate that the CSIRO and the Bureau of Meteorology did not undertake a prior evaluation of the models used in the first study of its kind in Australia in order to ensure that those models were able to reproduce the past situations that were relevant to the study.

The website of the Statistical Society of Australia Inc lists the names of more than 100 accredited statisticians who wish their contact details to be made public. There is now an opportunity for those experts who have the requisite skill and inclination to carry out their own analysis of the data used in the CSIRO/Bureau of Meteorology study and to report the results. In doing so, they would be performing a valuable public service.