MEDIA RELEASE: BOM refuses to answer on data records

 In Media, Media Release

LNP Senator for Queensland Gerard Rennick has called out the Bureau of Meteorology (BOM) during Senate Estimates today with key questions on their Surface Air Temperature dataset.

Despite repeated questions from Senator Rennick about the BOM’s confidence intervals on both its actual and adjusted records, the BOM refused to provide clear answers.

The BOM’s adjusted records, the ACORN-SAT dataset is a time series of daily temperature data from a network of 112 weather stations going back over 100 years in most cases.

Since 2011 the BOM has found it necessary to adjust Australia’s temperature record on two occasions. This process of ‘homogenisation’ is claimed to account for anomalies identified within the raw dataset.

The latest adjustments in the ACORN 2 dataset has increased warming from 0.8 degrees Celsius to 1.23 degrees Celsius from 1910 to 2016.

Senator Rennick asked if the BOM agreed that the homogenisation of Australia’s mean temperature data has effectively increased the rate of warming by more than 50% since 1910. The BOM failed to answer this question and instead sought to defend its adjustment methodology by referencing peer reviews over the past decade.

“If they can’t answer what should be a very straightforward question for them, then I think Australians should be concerned”, said Senator Rennick.

Senator Rennick then asked the BOM to state its accepted margin of error or tolerance level for the original (raw) dataset, ACORN 1 dataset and ACORN 2 dataset. Again the BOM failed to answer the question despite Senator Rennick asking the question more than three times.

The 2011 independent peer review report found that the BOM’s observation practices did not meet international best practice. Furthermore a key recommendation of the report was that the tolerance on temperature sensors be reduced significantly below the present +/-0.5 degrees which is significantly higher than the World Meteorological Organisations standard of +/-0.2 degrees. Another key recommendation of the review was that the BOM should specify statistical uncertainly values associated with calculating Australian national temperature trends.

Senator Rennick said the BOM’s failure to clarify or provide an update on these important recommendations is disappointing given the importance of measuring surface air temperature.

“I intend to submit additional questions on notice on this and related matters that I hope the Bureau of Meteorology will answer expeditiously and in full.”


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