A couple of days ago I reported on a landmark decision in the Queensland Land and Resources Tribunal. It was decided that operations at a coal mine in central Queensland could be expanded without any of the conditions sought by two environmental groups, inparticular that mining giant Xstrata avoid, reduce or offset the greenhouse gas emissions likely to result from the mining, transport and use of the coal from the mine.
The decision included comment from Tribunal President Koppenol that Professor Ian Lowe, an expert witness for the environment groups, had exaggerated greenhouse gas emissions by a factor of 218 in his evidence. Professor Lowe immediately hit back in comment to media claiming he had only got the facts wrong by a factor of 15.
I must say, this seems like rather a large amount!
A reader of this blog, Cinder (aka Alan Ashbarry) has done his own calculations and concludes the Professor overstated the emissions but by not quite as much as President Koppenol claimed:
Hi Jennifer,
The decision by the Queensland Land and Resources Tribunal is supported by a well argued assessment of the merits of the development of this mining enterprise. It also critically examines the evidence presented on behalf of the Queensland Conservation Council by its ‘Expert Witnesses’.
Whilst not privy to the verbal presentation of the witnesses we can see that the written evidence may be confusing to many. QCC witness, Dr Hugh Saddler, first calculated the emissions from the mine’s operations, the transport of the coal and then the use of that coal. Dr Saddler then determines an annual figure and a total mine life’s figure. He does so by using his own methodology rather than the Australian Greenhouse Office that he states “this calculation of emissions yields a higher figure than would be the case if the default emission factor given in the AGO Factors and Methods Workbook were used.” Dr Saddler did not provide the AGO figure.
In Dr Saddler’s written evidence http://www.envlaw.com.au/newlands5.pdf the calculated total annual greenhouse emissions and the total greenhouse emissions were compared with Australia’s total greenhouse gas emission including Land Use, Land Use Change and Forestry. A similar comparison was made with Global Annual emission (excluding LULUCF).
Dr Saddler’s comment “The total greenhouse gas emissions from the mining, transport and use of the 28.5 Mt of coal from the 15 year life of the Project (84 Mt CO2-e) are, therefore, equivalent to approximately 0.24% of international annual greenhouse gas emissions based on 2000 levels of emissions (of 34 Gt CO2-e).” appeared in Professor Lowe’s written evidence as
“To put the potential release of CO2 from the proposed mine extension into context, the lifetime emissions from the proposed mine extension … about 0.24 per cent of the current annual global release of greenhouse gases.”
The Chair of the Tribunal correctly points out that this should only be an annual comparison, and correctly points out that the 0.24% figure is calculated on the 15 year life of the mine. However in his attempt to correct the evidence of Professor Lowe who used Dr Saddler’s figures the Tribunal appears to have divided the annual emissions by 15 rather than the total of 15 years output.
The Tribunal should have calculated 84 Mt divide 15 years = 5.6Mt to determine annual, then divide by 34 Gt equaling 0.0164%, an overstatement by 14.63 times.
Such an error is understandable given the number of equations, calculations and comparisons presented to the Tribunal, and whilst it changes the order of magnitude of the exaggeration, it still shows an exaggeration. The correct figure still agrees with the conclusion that the mine’s annual contribution to annual global GHG emissions was “very small”.
The Tribunal also could have added the LULUCF figure of about 8Gt to the global annual figure or excluded the estimated 5.5 Mt per annum usage figure as it could have been argued that coal from another source would be used, thus this mine would not have a net impact on global use of coal.
Excluding the use of the coal, the mine’s operation and the transport of the coal is in the order of 0.1 Mt each year or 0.0003% of yearly Global emissions
It would appear that the expert evidence, by including comparisons of life time emissions and annual emission, has created a mathematical dilemma that is not easily understood by the lay person, and takes more than a 15 second grab on TV to explain.
This appears to be identical to the tactics employed by the Wilderness Society in Tasmania when they apply mathematical comparisons to official government figures in the forest debate, such as comparing today’s old growth forest to the area that estimated to have existed in the year 1750 even though the forest in 1750 was of all ages, and only a percentage would have been considered “Old Growth”.
The word “Statistics” can be found in a well known phrase attributed to Benjamin Disraeli and popularised by Mark Twain: “There are three kinds of lies: lies, damn lies, and statistics.”
As Wikipedia says this semi-ironic statement refers to the persuasive power of numbers, and succinctly describes how even accurate statistics can be used to bolster inaccurate arguments.
Cheers, Cinders
Jennifer Marohasy BSc PhD has worked in industry and government. She is currently researching a novel technique for long-range weather forecasting funded by the B. Macfie Family Foundation.