Since 2006, in between promoting numeracy in education, and examples of simple statistics using topical issues from the theory of Anthropogenic Global Warming (AGW) to illustrate points, I asked the question "Have these models been validated?", in blog posts and occasionally submissions to journals. This post summarizes these efforts.
Predictions of massive species extinctions due to AGW came into prominence with a January 2004 paper in Nature called Extinction Risk from Climate Read more [...] 25 com
Some time ago I had a brief discussion with Leif Svalgaard on ClimateAudit blog inspired by an exchange between Leif and David Archibald when the latter complained that Leif's TSI reconstruction was "too flat".
The sunspots exhibited cyclic variability in terms of the frequency of the cycles and that most thermostats work by pulse width modulation and some digital music with pulse frequency modulation. Both these work in a similar manner the thermal inertia of whatever the thermostat is controlling Read more [...] 23 com
Detecting bias in research is not so difficult when you know what to look for. The conclusions are not justified by the data. Instead, the data may confirm, be consistent with, (or not inconsistent with) the conclusions. Working against this however are basic human motives on the part of the writer, to find novel and interesting approaches, find significant results when nothing is there, to be accepted by their colleagues, to get grants and be published.
According to Geoffrey Miller (The Mating Read more [...] 4 com
Ian Castles organized a review of the Drought Exceptional Circumstances Report by two Accredited Statisticians, who also review my first report on the skill of the climate models.
The statisticians find inadequate validation of the models of drought, as well as suboptimal regionalization in the DECR. They also find my analysis lacked force, and so I have done additional analysis in line with their suggestions.
The last few posts in the series have consisted of reviews of an unsuccessful submission Read more [...] none
David R.B. Stockwell
February 4, 2009
A review by independent Accredited Statisticians, Brewer and Other [KB09], suggested that some claims in the report â€œTests of Regional Climate Model Validity in the Drought Exceptional Circumstances Reportâ€ [DS08] were premature. Additional tests suggested by KB09 support the claim made in the original report of â€œno credible basis for the claims of increasing frequency of Exceptional Circumstances declarationsâ€. The contributions Read more [...] one
K.R.W. Brewer1 and A.N. Other1
28 January, 2009
1. K.R.W. Brewer is an Accredited Statistician of the Statistical Society of Australia Inc. (SSAI) and a long term Visiting Fellow at the School of Finance and Applied Statistics within the College of Business and Economics at the Australian National University.
2. A.N. Other is a pseudonym for another Accredited Statistician of the SSAI who prefers to remain anonymous. Full responsibility for the content is taken by K.R.W. Brewer.
The Read more [...] 7 com
Below are Peter Gallagher's thoughts on the reviews of the submission to AMM. Contrast this with ac's impressions that "To my reading the reviewerâ€™s criticisms are reasonable and pertinent." It goes to show, that reasonable and unrelated people can see things in different ways. Where is the resolvability of fact in the review process? Consensus?
Thanks for sending me these papers.
Reading the reviews, it seems to me that your submission has been poorly understood by the Read more [...] none
The Financial Times recently reported on the Australian bushfires, linking them to increases in greenhouse gases. We take another look at the data in the DECR and find Australia is getting wetter not drier:
Scientists say Australia, with its harsh environment, is set to be one of the nations most affected by climate change.
â€œContinued increases in greenhouse gases will lead to further warming and drier conditions in southern Australia, so the [fire] risks are likely to slightly worsen,â€ Read more [...] 16 com
Peter Gallagher reports that even while the coals are still warm, some are already blaming the Victorian fires on increases in greenhouse gases.
The following summarizes indications of decline in droughts in Australia from 1900 to the present, compiled from data provided with the Drought Exceptional Circumstances Report. Some of this information was provided in the submission the the Australian Meteorological Magazine (more about this tomorrow). Drought is defined as the percentage of area with Read more [...] 6 com
A number of familiar tests, often used to evaluate the performance of models: R2 correlation, Nash-Sutcliffe efficiency and similarity of trends and return period, were reported here, noting not much evidence of skill in the DECR models compared with observations at any of these. I also said what a better treatment might entail but left that for another time:
The percentage of droughted area appears to be a â€™bounded extreme value, peaks over thresholdâ€™ or bounded POT statistic. The Read more [...] one
Posts over the next few weeks will be updates on the status of reviews myself and others have initiated of the Drought Exceptional Circumstances Report (DECR), by the CSIRO and Bureau of Meteorology (BoM).
It is prudent to subject your views to the rigors of peer review. It is the way to knowledge to search out feedback. So I thought why not share the opportunity with others, so can avail themselves of the wisdom of the leading experts, to learn and formulate their own opinion, not only about Read more [...] 12 com
A couple of days ago, Luke, a frequent commenter, sent in a number of links to a new Australian Government drought initiative. The Minister Tony Burke has appointed an Expert Panel to examine the social impacts of drought as part of its national review of exceptional circumstances (EC) funding, which argues for a major change, based on incentives rather than emergency aid. In a recent speech, Peter Kenny, chair of an expert panel looking at the social impact of drought said of the Drought Exceptional Read more [...] 4 com
One of the tests of climate models predicting drought in my review of the Drought Exceptional Circumstances Report was the correlation of predicted area under drought with actual observed area under drought. Lazar criticized my inclusion of the R-Squared (r2) coefficient, an issue I didn't follow up at the time.
â€¦ correlating model predictions for individual years of exceptional rainfall with observed years of exceptional rainfall! This ignores noise (internal variability in the climate Read more [...] 4 com
Geoff Sherrington has been drawing attention to some changes in the legal language attached to various emails and reports associated with the CSIRO and the Climate Adaptation Flagship (CAF). Since I have been posting up emails in an attempt to hold people accountable, I have been looking into the legality. In the case of reports, to what degree are the authors accountable for the accuracy of the contents? (Disclaimer: This post makes no representations or warranties regarding merchantability, Read more [...] 3 com
Below is the email received a month ago from Dr Andrew Ash, Director of the Climate Adaptation Flagship, promising a formal response to issues raised about the Drought Exceptional Circumstances Report (DECR) concerning no apparent attempt at validation of the climate models for drought in the report, or evidence of skill at modeling drought. No reply has been forthcoming to date.
date Tue, Sep 16, 2008 at 2:35 PM
subject RE: Drought Exceptional Circumstances Report
Dear Read more [...] 14 com
Support was expressed for our efforts with the DECR from a reader of the Sydney Morning Herald below.
Letters to the Editor, Sydney Morning Herald - 4 Oct 2008
Meanwhile, the Department of Climate Change is hiring in a big way! Need I say you could get a lot of economically productive research done in almost any hard science area with a unit this size.
Employment Section, The Australian - 11 Oct 2008.
Alan Sullivan diagnoses the financial turmoil in a memorable alliteration -- Laughable Left. Read more [...] 16 com
"Climate change could devastate fishing industry: CSIRO" shouts the ABC news, as scientists predict the salmon, rock lobster and abalone industries, barramundi, prawn and mudcrab fisheries will be affected by changing rainfall patterns. In a welcome trend, the fishing industry have questioned the climate findings in the CSIRO report.
Industry representatives see the report contributing nothing new, and self-serving for the global warming scientists:
"In fact, the report itself is not much more Read more [...] 13 com
The venue for more formal debate on controversial topics is the scientific journals. As part of my trek into the desert of drought predictions in Australia, I submitted a review of the Drought Exceptional Circumstances report (abstract below) two days ago to the Australian Meteorological Magazine. To date I have not received an acknowledgement of its receipt.
The reasons I selected the AMM: it publishes all its papers on the web, has emphasis on the meteorology of the Australian region and the Read more [...] 2 com
Changes in the exceptionally dry years (droughts) have been estimated in the Drought Exceptional Circumstances Report (DECR) in two ways: (a) a statistical modification of the observed rainfall data (Box 3); and (b) analysis of simulations from 13 climate models. Up until now I have been looking at the modeling in approach (b). Today I started to look at approach (a). As mean rainfall declines the probability of exceptionally low rainfall increases. This is graphed in Box 3 (see also Table 6).
The Read more [...] none
Any claims or representations made by a business must be accurate and truthful. If a business has been dishonest, exaggerated the truth, or created a misleading impression, then there is a very broad provision in the Trade Practices Act to prohibit such conduct by a corporation.
For example, the ACCC webpage on misleading and deceptive conduct gives an example of a business predicting the health benefits of a therapeutic device or health product but having no proof that such benefits can be attained. Read more [...] 21 com
Following up on the post from yesterday, I test the assumption underpinning the regional climate change work in Australia.
The most common approach has been to assess how well each of the available models simulates the present climate of the region (e.g. Dessai et al. 2005), on the assumption that the more accurately a model is able to reproduce key aspects of the regional climate, the more likely it is to provide reliable guidance for future changes in the region.
As far as I can see this is Read more [...] none