JoNova

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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Excuses Excuses! Neville Nicholls and the Stevenson screens that didn’t exist or did and were “cracked”?

Neville Nicholls and Sophie Lewis are striking back at George Christensen, MP, who accused the BOM of “wiping” the official records of heat waves in 1896 and demanded an inquiry. For some reason, despite their world class work, Nicholls and Lewis still don’t seem keen on having an inquiry — so they go to some length to explain why it’s “false” to say it was hotter in 1896 than it was in 2013. Oddly though, to come to this conclusion they don’t use BOM work, because the BOM concluded “it would be very difficult to compare the 19th-century temperature data with modern observations.” Instead that difficult task was done by Berkley. Nichols calls it “brave”, but a “fact” at the same time.

In their long article, what they don’t explain is why they almost never mention any of the hundreds of ultra hot historic temperatures in their press releases and national news. George was “wrong”, and that’s a “fact” we’re told, but most of their article  on The Conversation explains why we don’t know what the temperature was in 1896. Try not to get confused.

That old data is dodgy see — I’ll paraphrase: Satellites agree with the BOM.  (Seriously, this [...]

Australian summer maximums “warmed” by 200%

Which causes more summer heatwaves: carbon dioxide or Bureau of Meteorology (BOM) adjustments?

Ken Stewart has analyzed the adjustments used to create the all-new ACORN wonder dataset and compared them with another BOM dataset called AWAP, and finds, extraordinarily, that the trend in average summer maximums has been tripled by adjustments that the BOM imply are neutral.

Since summer maxima are the ones used to generate the most headlines in Australia, I ask again if the Bureau of Meteorology is a scientific agency or a PR group?  Increasing the trend in summer maxima would produce more headlines of hottest ever month, season, heatwave, and weekend.

In this graph Stewart splits the data into months, and compares the trends in maxima in the AWAP and ACORN datasets, across the entire nation. We see that most of the adjustments happen to data from the hottest months of the year, October to March. Even though the measured maxima in February and March are possibly cooler now than they were in the early 1900s, they have been adjusted to show warming trends.

When was the last time you heard the BOM tell you that their “hottest ever” February record depended on adjusting down the [...]

The lost climate knowledge of Deacon 1952: hot dry summers from 1880-1910

Once upon a time, Australian climate scientists discussed and published climate trends of the late 1800s. And lo, the long lost hot weather decades were apparent in many places in inland South Eastern Australia. While skeptics are accused of cherry picking data from Bourke, Rutherglen and Deniliquin, there are plenty of other examples. In the last post, the 1953 Argus story described hotter drier summers in Omeo, Bendigo, Hay, Bourke, Alice Springs, Echuca, Albury, and Cooma. Here is a Deacon et al peer reviewed graph of the long term trends at Hay, Narrabri, Bourke and Alice Springs.

Thanks to Chris Gillham for finding the Deacon paper of 1952. [On another point, I'll have a response up to the new BOM "adjustments" page later. In short, their data still has many inexplicable errors like where maxima are lower than minima, and they are still not providing all the details we need to replicate their data and homogenization methods. - Jo]

But just have a look at this graph. Degrees Fahrenheit of course. State of the art, 1952.

….

These  cooling trends cover “only” a couple of million square kilometers of Australia:

The location of Alice Springs, Bourke, Narrabri, and [...]

1953 Headline: Melbourne’s weather is changing! Summers getting colder and wetter

The average maximum temperatures [of SE Australia] during the last 35 years were between two and four degrees (F) lower than the average for the previous 35 years. — CSIRO 1953

Once upon a time — before the Great Politicization of Climate Science — CSIRO was able to analyze trends from 1880 to 1910. In 1953 CSIRO scientists were making a case that large parts of Australia had been hotter in the 1880s and around the turn of last century. They are referring specifically to summer maximums, and presumably the increase in rainfall over the same period played a large role in preventing hot days from becoming hotter. Minimum and mean trends may have been quite different, but these older maximum records are surely relevant when news headlines are drafted today about hot summers and heatwaves.

So what happened to the widespread lost hot decades?

I have a lot more to say on the warm and the work of these scientists. For the moment, the full archived news story is entertaining in its own right. Thanks to Chris Gillham for this link and to Jennifer Marohasy. Graphs tomorrow : – )

– Jo

 

The Argus (Melbourne, Vic) Wednesday 18 March [...]

BOM homogenisation in Deniliquin creates discontinuities and changes trends

The list goes on, and there is more to come.

In Deniliquin NSW, the homogenisation has lifted both the maxima and minima trends — again converting cooling to warming.

Graham Lloyd continues to increase the pressure on the Australian Bureau of Meteorology. In answers to Lloyd the BOM could only defend their work with the extraordinary statement that while some trends at individual stations look anomalous, overall the results “showed a similar warming trend to that of other inter­national climate ­organisations. ”

So they inadvertently admit that they expect Australian trends to look like trends in other parts of the world. Despite the fact that Australia is drier, flatter and surrounded on every edge by oceans, the Bureau would consider it a fail if our trends were different to others? We’re in the opposite hemisphere to many international climate organizations, which may or may not matter, but we’ll never find out if we are trying to fit our data to theirs. And El Nino’s and La Nina’s mean very different things to countries on opposite sides of the Pacific. We’re blurring the resolution from thousands of data-points. The raw data is blended not just on regional scales but thanks to [...]

The mysterious lost hot Sunday in Bourke, did it really happen?

 Was January 3rd 1909 in Bourke one of Australia’s hottest days ever?

The historic records say “125F” — or 51.7C. The BOM say it was an observer error.

Bourke and neighboring stations in NSW and QLD Australia

Blair Trewin wrote a paper looking at the extreme highs in 1997. The Bourke record was made on a Sunday and in that particular year there are no records on other Sundays. On the other hand, I wonder what station observer would not notice a day that was 125F and head in to work to see exactly how high it was. The number 125F was handwritten in and underlined. You’d think observers would know it was a special figure, and pay attention.

The town of Bourke got a Stephenson Screen only a few months beforehand in August 1908, so it had good modern equipment. But Trewin thinks the record is an observer error, and points out that it was a lot warmer in Bourke than in other surrounding towns like Thargomindah, Walgett, and Coonable, and by about 6.9C degrees, which is an unusual gap. During the rest of the month Bourke was “not exceptionally hot compared to other stations”. Fair point. [...]

Explain this? Rutherglen homogenized with 17 stations including Hillston!

We’ve seen the remarkable change of the Rutherglen record as it got homogenized. This long running rural record that looks ideal apparently had “unrecorded” station moves found by thermometers miles away.  Already we have found Bill Johnston who did some work at Rutherglen who confirmed that the station did not move. The mystery grows?

Since early 2012 Ken Stewart has been asking the BOM which neighbouring stations were used.  Finally, after pressure from The Australian, the BOM has provided the 17 names, and Ken has graphed them.

Follow the chart below. Rutherglen temperatures start off in blue. The yellow line is the average of the 17 “neighbours” which are used to homogenize that blue line and transform it into the red one which somehow ends up being colder than its neighbours in 1952  and warmer than its neighbours in all the last 30 years.

See if you can figure it out?

Rutherglen starts off blue. Then the yellow line is used to homogenize that blue line into the red one.

Presumably the BOM technique would be a lot more complicated that what Ken has done, but clearly replicating that ACORN final trend is not going to be easy.

The [...]

Hiding something? BOM throws out Bourke’s hot historic data, changes long cooling trend to warming

Hello Soviet style weather service? On January 3, 1909, an extremely hot 51.7C (125F) was recorded at Bourke.  It’s possibly the hottest ever temperature recorded in a Stevenson Screen in Australia, but the BOM has removed it as a clerical error. There are legitimate questions about the accuracy of records done so long ago — standards were different. But there are very legitimate questions about the BOMs treatment of this historic data. ‘The BOM has also removed the 40 years of weather recorded before 1910, which includes some very hot times. Now we find out the handwritten original notes  from 62 years of the mid 20th Century were supposed to be dumped in 1996 as well. Luckily, these historic documents were saved from the dustbin and quietly kept in private hands instead.

Bourke has one of the longest datasets in Australia — but the BOM, supposedly so concerned about the long term climate trends, appears to have little curiosity in the hot weather of the 1880′s and 1890′s (I talked about the amazing heatwave of 1896 here where hundreds died and people in Bourke escaped on special trains). If it had been a cool spell then, would the BOM feel [...]

Big adjustments? BOM says Rutherglen site shifted, former workers there say “No”

The hot questions for the Australian Bureau of Meteorology (BOM) mount up. Rutherglen was one of the temperature recording stations that was subject to large somewhat mysterious adjustments which turned a slight cooling trend into a strongly warming one. Yet the official notes showed that the site did not move and was a continuous record. On paper, Rutherglen appeared to be ideal — a rare long rural temperature record where measurements had come from the same place since 1913.

The original cooling trend of  – 0.35C was transformed into a +1.73C warming after “homogenisation” by the BOM. To justify that the BOM claims that there may have been an unrecorded shift, and it was “consistent” with the old station starting  further up the slope before it moved down to the hollow.

Today retired scientist Bill Johnston got in touch with Jennifer Marohasy, with me and with Graham Lloyd of The Australian to say that he worked at times at Rutherglen and the official thermometer had not moved. It was always placed where it is now at the bottom of the hollow. That information has already made it into print in The Australian.

The original thermometer records suggest a [...]

BOM finally explains! Cooling changed to warming trends because stations “might” have moved!

It’s the news you’ve been waiting years to hear! Finally we find out the exact details of why the BOM changed two of their best long term sites from cooling trends to warming trends. The massive inexplicable adjustments like these have been discussed on blogs for years. But it was only when Graham Lloyd advised the BOM he would be reporting on this that they finally found time to write three paragraphs on specific stations.

Who knew it would be so hard to get answers. We put in a Senate request for an audit of the BOM datasets in 2011. Ken Stewart, Geoff Sherrington, Des Moore, Bill Johnston, and Jennifer Marohasy have also separately been asking the BOM for details about adjustments on specific BOM sites. (I bet Warwick Hughes has too). The BOM has ignored or circumvented all these, refusing to explain why individual stations were adjusted in detail.

The two provocative articles Lloyd put together last week were  Heat is on over weather bureau  and  Bureau of Meteorology ‘altering climate figures, which I covered here. This is the power of the press at its best. The absence of articles like these, is why I have said the media [...]