Here is an email from Hennessy about the CSIRO/BoM Drought Exceptional Circumstances Report. He raises some classic chestnuts that are easily dispatched:
date Mon, Aug 25, 2008 at 9:26 AM
subject RE: climate model evaluation
We are not withdrawing the DEC report because we are satisfied with the model evaluation done prior to publication.
Bill Venables was engaged to help with understanding what you’ve done, not what we’ve done.
Note that we don’t do predictions. You won’t find this word anywhere in the DEC report. We provide projections that are conditional on various assumptions and uncertainties, as explained on page 18 of the report.
1. “we are satisfied with the model evaluation”
This would be the evaluation that they won’t reveal. Assuming they did the evaluation as Kevin claims, there are two possibilities. Either the evaluation showed the models had skill, or not. If they knew the models had no skill at drought, and then claimed that “the analysis showed that increased droughts are more likely”, that would be misleading.
The CSIROpod interview shows that they knew that the models had no skill at exceptional low rainfall:
(1:20m) … there has not been a clear indication of changes in exceptional low rainfall years.
(1:40m) … but in terms of a long term trend its not very clear in terms of exceptional low rainfall years.
2. “Bill Venables was engaged to help with understanding what you’ve done, not what we’ve done.”
Wouldn’t the best rebuttal of my critique be to simply produce evidence the models had skill?
3. “Note that we don’t do predictions. You won’t find this word anywhere in the DEC report.”
Below are a number of times the prediction has been used.
a. DEC report Page 23: The development of seamless prediction systems on relevant timescales.
b. The CSIROpod interview Hello and welcome to CSIROpod. Iâ€™m Nari Creed. Everyone who eats or grows food should be very worried by a new report from CSIRO and the Bureau of Meteorology which predicts that climatic events considered exception in the past may become more common in the future.
c. The ABC: â€œA new report is predicting a dramatic loss of soil moisture, …”
d. DAFF’s own press release (does this count?): “Australia could experience drought twice as often and the events will be twice as severe within 20 to 30 years, according to a new Bureau of Meteorology and CSIRO report.”
Seems like a lot of people thought the report ‘did’ predictions. I guess the statements in the summary like the following had them all fooled.
“The current EC trigger, based on historical records, has already resulted in many areas of Australia being drought declared in more than five per cent of years, and the frequency and severity are likely to increase.”