A science presenter, writer, speaker & former TV host; author of The Skeptic's Handbook (over 200,000 copies distributed & available in 15 languages).


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Wow, look at those BOM adjustments – trends up by two degrees C!

The mystery of Australian temperature adjustments

Ken Stewart has been checking the Australian BOM official ACORN minima data against the raw data. This week he highlights the six very strange cases of Brisbane Airport, Amberley RAAF, Dubbo, Rutherglen, Rabbit Flat, and Carnarvon. In all these places the adjustments change the trend by more than 2 whole degrees C. It’s a kind of hyper-homogenization.

Thermometers are supposed to be accurate to a tenth of a degree. Australian average trends are sometimes calculated to one hundredth of a degree. What then do we make of adjustments that change the trends by a whopping 2 degrees, and decades after the data came in? The only thing we know for sure about Australian temperatures is that we need an independent audit. Why is it left to volunteers to check? Surely the Greens want good data too?

Some of these stations are isolated outposts, so theoretically they are the heavyweights on Australian area-weighted averages. The map scales can be a bit deceptive. In outback Australia the nearest neighbours can all be 500 km away (300 miles). Some dots on the map are not so much a town as a motel and a gas station. [...]

Australian BOM “neutral” adjustments increase minima trends up 50%

UPDATED, Ken has now finished the full tally of comparisons and the adjustments to minima increase trends by 47% . (Headline changed from 60% to 50% to reflect the shift.) See the new details of the last few stations at KensKingdom.

Billions of dollars, climate models, predictions, and hundreds of press releases depend on the BOM records of Australian temperatures. There were so many inconsistencies, inexplicable adjustments and errors that we put in a Senate request for the ANAO to audit the records. In response, to dodge the audit, the BOM dumped its HQ (“high quality”) dataset entirely, and established a new “best practise” ACORN dataset.

Independent volunteer auditors have been going through the ACORN records — thanks especially to Ken Stewart who is publishing his findings on his site as he works through the set. He’s analyzed 84 out of  104 sites, and finds that ACORN is just as bad as the HQ set. At Kenskingdom he shows that so far, the adjustments used to create the official Australian temperature record increase the warming trend by13% for maxima and a whopping 66% for minima. (Note the caveats in the conclusions below.)

The raw Australian data suggest the [...]

Hottest summer record in Australia? Not so, says UAH satellite data

There are probably only ten people in Australia who haven’t heard it was the Hottest Ever, Record Summer Downunder. And they were probably born yesterday.

Summer here was so scorchingly awful it was Angry. But a funny thing happened on the orbit overhead. Check out the UAH satellite data on summers since the UAH records began.  The graph below (thanks to Ken) is the temperature data from the NASA satellites, processed by UAH (University of Alabama in Huntsville). Strangely there is a disparity between what the satellites recorded and the BOM.

The satellite data shows that the summer of 2012-2013 was close to ordinary, compared with the entire satellite record going back to 1979. Not a record. Not even extreme?

According to UAH satellite measurements summer in early 2013 was not a record. Not even close.

The graph data comes thanks to John Christy, Director, Earth System Science Center, Distinguished Professor, Atmospheric Science University of Alabama in Huntsville, Alabama State Climatologist and Roy Spencer. It was graphed by Ken Stewart at KensKingdom, and inspired by Tom Quirk at Quadrant. I was very happy to connect them this weekend. The data cover “average lower troposphere temperature anomalies for land grids [...]

Mystery black-box method used to make *all new* Australian “hottest” ever records

There were not many long term sites (in black dots) in the centre of Australia in 1930.

This summer the Bureau of Meteorology (BOM) invented a whole new metric to measure average national heat, which might be all very well except no-one (other than the BOM) seems to know what it is.

On January 7th the BOM claimed Australia set a new “average maximum daily temperature record”. Now the headlines are about the “hottest” Australian summer.

With both records, no one outside the BOM team has access to the methods or data. This post is about the new “daily” temperature of Australia used to declare Jan 7th was a record, but the same point applies to the “hottest summer” records, even though they may be a different data set. Where is the data? Where are the methods?

Is the BOM a science agency or a PR bureau?

The January 7th heatwave supposedly broke all previous “daily” records in this category — a dubious honor since no-one can remember any records like it.

It’s a bit like winning the Side-Jump. It’s not an event anyone knew was on until the medal ceremony. Worse, no one knows how the [...]

Threat of ANAO Audit means Australia’s BOM throws out temperature set, starts again, gets same results

Joanne Nova and Ken Stewart

A team of independent auditors, bloggers and scientists went through the the BOM “High Quality” (HQ) dataset and found significant errors, omissions and inexplicable adjustments. The team and Senator Cory Bernardi put in a Parliamentary request to get our Australian National Audit Office to reassess the BOM records. In response, the BOM, clearly afraid of getting audited, and still not providing all the data, code and explanations that were needed, decided to toss out the old so called High Quality (HQ) record, and start again. The old HQ increased the trends by 40% nationally, and 70% in the cities.

So goodbye “HQ”, hello “ACORN”. End result? Much the same.

That meant the ANAO could avoid an audit, since the BOM had changed data-sets, the point of auditing the old set was moot.

For me, this version is so much worse than the previous one. In the HQ data set the errors could have been inadvertent, but now we’ve pointed out the flaws, there can be no excuses for getting it wrong. Instead of fixing the flaws (and thanking the volunteers), it’s almost as if they’ve gone out of their way [...]

Australian temperature records shoddy, inaccurate, unreliable. Surprise!

The BOM say their temperature records are high quality. An independent audit team has just produced a report showing that as many as 85 -95% of all Australian sites in the pre-Celsius era (before 1972) did not comply with the BOM’s own stipulations. The audit shows 20-30% of all the measurements back then were rounded or possibly truncated. Even modern electronic equipment was at times, so faulty and unmonitored that one station rounded all the readings for nearly 10 years! These sloppy errors may have created an artificial warming trend. The BOM are issuing pronouncements of trends to two decimal places like this one  in the BOM’s Annual Climate Summary 2011 of “0.52 °C above average”  yet relying on patchy data that did not meet its own compliance standards around half the time.  It’s doubtful they can justify one decimal place, let alone two?

We need a professional audit.


A team of independent engineers, scientists, statisticians and data analysts (brought together by the joannenova blog) has been going through the Australia Bureau of Meteorology records (BOM). They’ve audited some 8.5 million daily observations across 237 High Quality and other close sites in Australia. Shockingly, while [...]

Australian sea level rises exaggerated by 8 fold (or maybe ten)

The Daily Telegraph exposed the NSW state government protecting the world from some dangerous scientific analysis of sea-levels. The officials pulled papers and posters within days of when they were due to be released, late in September 2011. Doug Lord examined 120 years of tidal data from Sydney Harbour, and found a 1 mm year on year rise which didn’t fit with the 900 mm rise projected by the Wizards of Climate Change at the Department. He finds the official figures exaggerate ten fold.

Ken Stewart has taken the dangerous data from 19 sites around Australia and finds it averaged 1.4 mm/year over the last 100 years. He finds about an 8-fold exaggeration. This is another sordid tale in the Science-perverted-for-PR category.

Sea Level Change in Australia: What’s Likely?

The mean sea-level rise recorded at 19 stations around Australia (warning, data is limited in the first half of the series). The trend is a steady rise. The last 20 years is not unusual.

Seas have been rising in a reasonably continuous trend around the world since 1800.  The last two decades are not unusual.


Announcing a formal request for the Auditor General to audit the Australian BOM

A team of skeptical scientists, citizens, and an Australian Senator have lodged a formal request with the Australian National Audit Office (ANAO) to have the BOM and CSIRO audited.

The BOM claim their adjustments are “neutral” yet Ken Stewart showed that the trend in the raw figures for our whole continent has been adjusted up by 40%. The stakes are high. Australians could have to pay something in the order of $870 million dollars thanks to the Kyoto protocol, and the first four years of the Emissions Trading Scheme was expected to cost Australian industry (and hence Australian shareholders and consumers) nearly $50 billion dollars.

Given the stakes, the Australian people deserve to know they are getting transparent, high quality data from the Bureau of Meteorology (BOM). The small cost of the audit is nothing in comparison with the money at stake for all Australians. We need the full explanations of why individual stations have been adjusted repeatedly and non-randomly, and why adjustments were made decades after the measurements were taken. We need an audit of surface stations. (Are Australian stations as badly manipulated and poorly sited as the US stations? Who knows?)

Australian Temperatures in cities adjusted up by 70%!?

Ken Stewart has been hard at work again, this time analyzing the Australian urban records. While he expected that the cities and towns would show a larger rise than records in the country due to the Urban Heat Island Effect, what he found was that the raw records showed only a 0.4 degree rise, less than the rural records which went from a raw 0.6 to an adjusted 0.85 (a rise of 40%). What shocked him about the urban records were the adjustments… making the trend a full 70% warmer.

The largest adjustments to the raw records are cooling ones in the middle of last century. So 50 years after the measurements were recorded, officials realized they were artificially too high? Hopefully someone who knows can explain why so many thermometers were overestimating temperatures in the first half of the 1900′s.

50 years later?

The raw Australian urban temperature records are in blue. The adjusted records in red. Note that temperatures in the middle of last century appear to be adjusted downwards. These are the annual average recordings for all 34 sites.

Remember Dr David Jones, Head of Climate Monitoring [...]

Australian warming trend adjusted UP by 40%

Ken has been a very busy man. Another soul in the dedicated army of volunteer auditors. He’s been going through the entire Australian High Quality Data Set as supplied by the Bureau of Meteorology (BOM). He’s been assisted by two readers from this site — Lance and Janama — and we’ll be looking to increase the team (see below).

In the State of the Climate  report, both  the BOM and CSIRO told us that “since 1960 the mean temperature in Australia has increased by about 0.7 °C. The long term trend in temperature is clear… ” but as usual, what they didn’t say was that the raw data since 1910 (not just from 1960) increased only 0.6°C.

The BOM claim their adjustments are random and neutral. Yet when Ken looked at the raw data from Australia’s 100 high quality rural sites, the adjustments increased the trend in the raw data by 40% — from a 0.6°C rise over 100 years, to 0.85°C over 100 years.

In an email to Ken, Dr David Jones, Head of Climate Monitoring and Prediction, National Climate Centre, Bureau of Meteorology, made a clear claim that the adjustments had no [...]