Are heatwaves in Australia becoming more frequent, hotter or lasting longer?

By: Geoffrey H Sherrington 
Scientist

The hypothesis tested.

We test this hypothesis:

Heatwaves in Australia are becoming more frequent, hotter and are lasting longerbecause of climate change.

(The claim was made in a Climate Council report of Jan 2014. From other publications, it seems to be perceived wisdom among authorities from the Australian Bureau of Meteorology and CSIRO, who help to guide national policy.)

Here, we examine the daily maximum temperatures of 5 State capitals, Perth, Adelaide, Melbourne, Sydney and Hobart. These were chosen because many people live close to these weather stations and because their observations cover many decades. Brisbane has too much missing temperature data and Darwin is already hot.

We use simple algebra and 5 sites only because of limited resources. However, more complicated analysis must still explain the findings of simple tests.

There is no settled definition of ‘heatwave’ yet. Australia’s Bureau of Meteorology, BOM, is currently creating more complex definitions, commonly in terms of 3 day heatwaves. 

Here, for ease of calculation, a heatwave is simply defined as a string of consecutive days whose average of the maximum temperatures is anomalously high. We look at past heatwaves of 4, 5, 6 and 10 consecutive days. We select the Top 20 hottest heatwave years and then rank them in various ways.

There are two relevant data sets, both from the Australian Bureau of Meteorology (BOM) whose compilation of the historical record is acknowledged. The first set is the longer one, called CDO for Climate Data Online. This is essentially raw data as recorded. The second set is the BOM ACORN-SAT, or Acorn for short, which is an adjusted, homogenised set that usually commences in 1910. As time goes by, more announcements are made in Acorn terms, when sometimes it is more appropriate to use raw data, so we test both.

Thus, we present a bundle of graphs, being 5 cities x 2 data sets X 3 heatwave day lengths for a total of 30 graphs. Averaged maximum daily temperatures in degrees C always form the Y axis, years always form the X axis. 

The primary finding:

The hypothesis is falsified for the cities tested.

That is, it is wrong to claim that in these important cities at least, there has been such a change of the characteristics of heatwaves as defined.

Findings in more detail.

Here is one example of the 30 graphs used in the first stage of the analysis. The temperature data are from the BOM CDO for the Sydney Observatory station 66062.

To create this graph, the daily maximum temperature, after some minor infilling of missing data, was searched for every value of the hottest 4 consecutive days. Each 4 day average was ranked from hottest to coldest, then a Top 20 hottest selection was made, with any year appearing only once. (Rarely, some years have 2 Top 20 events, but we used only the hotter).

For most of the graphs, the years are shown in chronologic order of oldest to most recent. The linear regression line has no great mathematical meaning; it is inserted to help the eye to see if there is a discernible trend over the years. The line is coloured blue for a cooling trend, yellow for essentially zero trend and red for a warming trend.

To avoid having to count from the 30 graphs, here is a summary table of trends:

Test One: Are heatwaves becoming more frequent?

We answer this by counting the number of heatwaves in the first half and second half of the years of each chronological Top 20 data set. The longer, CDO data set is used. Here is a table to summarise the findings.

Findings: There is a mixture of results depending on site location. Perth has more heatwaves since 1956, than before then. Adelaide has the opposite, with many more heatwaves before 1950, than after 1950.

There is not a strong pattern for Melbourne, Sydney, or Hobart.

The hypothesis that heatwaves are becoming more frequent is then supported by one city only of the 5 tested, Perth. Note that the results for Perth and indeed all stations, can vary if a different selection of local weather stations is chosen.

Test Two: Are heatwaves becoming hotter?

This is answered by the trends of the heat wave Top 20 in chronological order.

Each chronological list was divided into the earliest 10 of the Top 20 years and the later 10 years. The average temperature of each early set of 10 was compared with the average of each later set of 10. This later number, for each of the 5 sites, was subtracted from the earlier number to show a temperature rise or fall over the history. A positive number is taken to mean that there is cooling over the years.

The outcome is shown in this table. In all but one case out of 15, (Sydney, Acorn, 5 day) these data show heatwaves are getting cooler with the passing of time.

Test Three: Are heatwaves becoming longer?

We introduce 10 day heatwave calculations through graphs such as this one for Adelaide. 

In this example, it can be seen that the long, 10 day heatwaves are no more prevalent in the second half of the history than the first half, 1887 to 1950. It is concluded for this case that heat waves are not becoming longer. The following table summarises all 15 CDO cases calculated.

NUMBER OF TOP 20 CASES

The result is a mixed bag. This method of analysis suggests that later heatwaves have been dominantly longer in Perth, because only 1 case appears before the half-way point. Conversely, early heatwaves are dominant in Hobart, with not a strong signal in Adelaide, Melbourne or Sydney.

The hypothesis that heatwaves are becoming longer is not supported by this analysis of these 5 important cities.

CONCLUSIONS.

It is easy to raise objections to the methodology of this analysis.

It is not easy to explain why perceived wisdom supports the opening hypothesis of longer, hotter and more frequent heatwaves, when this simple exercise falsifies it in the first instance.

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Now re-blogged by Jo Nova - HERE

Climate Scientists' Major Fail.

Prof. Stewart William Franks, Professor of Environmental Engineering at the University of Tasmania holds a BSc(Hons) in Environmental Science and a PhD, both from Lancaster University (UK). Since 2013, Stewart has been the Foundation Chair of Environmental Engineering at the University of Tasmania.

He has written a piece in the IPA's Climate Change: The Facts 2014. He exposes the flaws in some of the "climate science".

For Instance:

What dismays me the most is that the worst examples of speculative claims often come from the scientists themselves. Commentators from the Bureau of Meteorology and the CSIRO are among the worst for making statements that are simply incorrect. 

One stated, ‘of course, the drought has not been helped by rising temperatures, which have increased losses through evaporation,’ and ‘it is very difficult to make a case that this is just simply a run of bad luck driven by a natural cycle and that a return to more normal rainfall is inevitable, as some would hope.’ (David Jones, BoM)

Stewart  says that a report from(David Karoly)WWF followed this same flawed science:

The higher temperatures caused a marked increase in evaporation rates, which sped up the loss of soil moisture and the drying of vegetation and watercourses. This is the first drought in Australia where the impact of human-induced global warming can be clearly observed.

Then Stewart shows where this is flawed: (bold added)

While this may sound intuitively correct, it is wrong. It completely ignores the known science of evapotranspiration and boundary layer meteorology. That is, when soil contains high moisture content, much of the sun’s energy is used in evaporation and consequently there is limited heating of the surface. However, during drought, soil moisture content is low and consequently nearly all of the incoming radiation is converted into heating the surface. 

Stewart moves on to statements by Kevin Trenberth

Dr Kevin Trenberth, who leads the IPCC science, provided all the inspiration required in a recent paper entitled: "Framing the way to relate climate extremes to climate change." 

Remember Dr Trenberth?  "It's a "travesty" that "we can't account for the lack of warming.." 

Perhaps Kevin should have describes his latest peer reviewed paper as a travesty.

His essential message was that to ask ‘to what degree climate change contributed to an event’ is actually to ask the wrong question. His message is that every event is influenced by climate change. The implication of this is that because the science cannot answer the question, it doesn’t have to—scientists should just claim everything is a sign of climate change.   

It concluded that everything that happened that summer was due in part to climate change. This is the kind of science many might prefer to the real thing—a science where one doesn’t actually have to do anything to justify one’s claims. In reality, Trenberth’s framing of the climate science debate has little to do with science—it is merely advocacy for a catastrophic future outlook.

Next Stewart describes "One very Unfortunate event."

.....a paper was published in the journal Nature which claimed to have linked increases in rainfall to anthropogenic climate change.

Why unfortunate? Well.....

Expert commentators were sought to evaluate its meaning. To paraphrase, one climate scientist announced that ‘it was published in Nature, so it must be right’, another claimed that ‘we already knew this, so it only confirms what we already thought’. Such comments could have been as easily made without even bothering to read the paper. No critical analysis was ever provided. (bold added)

The Paper:

Human contribution to more-intense precipitation extremes: Min et al - Nature - doi:10.1038/nature09763

The paper must have hit the spot with Alarmist scientist for it has been cited 528 times (link)

Figure 1

There is however one rather major problem with the paper—the study never did compare the calculated rainfall probabilities against the corresponding temperature. If they had, they would have noted that there was no correlation at all between the two. (bold added)

The figure above shows the five year average one-day rainfall probabilities (dark blue line) from 1951 onwards. There is a spike at the end, but no substantive evidence for a consistent trend. 

The light blue line shows northern hemisphere temperature anomalies for the same periods. 

Wha-a-a-a??? Here is a peer reviewed (or should that be pal reviewed) paper that fails to show what it set out to do. Can we have a list of the scientists who missed the fact that there was no correlation, please?

As Stewart explains:

Note that between 1951 and 1980, temperature anomalies were declining, whilst half of the apparent increase in rainfall occurred. There is no correlation between temperature and rainfall intensities. Nor should there be—rainfall processes are far more complicated than being driven simply by temperature. 

Climate Predictions from the Dunces Corner

Tony Thomas, writing for Quadrant Magazine:

Anyone can be a prophet of doom: Pick a spot on the globe, any spot, and state with oracular authority that it will suffer most from runaway climate change. Tim Flannery fancied Perth, for example, which has yet to become his predicted ghost town, but he has plenty of company in the dunce's corner.

 Tony writes that public concern for the supposed catastrophic warming of the planet has been falling for years. He notes that " even on the CSIRO’s figures, Aussies rank climate fourteenth out of sixteen concerns overall, and we rate it only seventh out of eight even among environmental concerns."

Partly to blame is that dratted 18-year halt to global warming, even as man-made CO2 continues to pour into the skies. But my theory is that the global warming industry has made itself so ridiculous over the past 30 years, so hyperventilatingly ludicrous, by predicting ever-more-dire catastrophes by the year 20XX.  But then year 20XX   comes and goes and life continues as normal.

He references Anthony Watt's  Climate FAIL Files:

The Claim: 50 million climate refugees will be produced by climate change by the year 2010. Especially hard hit will be river delta areas, and low lying islands in the Caribbean and Pacific. The UN 62nd General assembly in July 2008 said:  …it had been estimated that there would be between 50 million and 200 million environmental migrants by 2010.The Test: Did population go down in these areas during that period, indicating climate refugees were on the move? The answer, no. 

Tony then moves on to Flim Flam Flannery's

Tim Flannery is sticking by his warning that Perth could become the first ghost metropolis of the 21st century.

James Patterson points out that the Flim Flam man also predicted that Sydney would run out of water by 2006. FAIL!

 In 2004 he predicted that ‘Perth will be the 21st century's first ghost metropolis.' The following year, he said that Sydney could run out of water in as little as two years.
Undaunted by that botched prediction, he tried again in 2007, saying Adelaide, Sydney and Brisbane would ‘need desalinated water urgently, possibly in as little as 18 months.'

 As well as running out of water, Flannery (and James Hansen) also said that oceans would rise 25 metres: (link)

James Hansen........ predicts that we have just a decade to avert a 25-metre rise of the sea. Picture an eight-storey building by a beach, then imagine waves lapping its roof. That's what a 25-metre rise in sea level looks like. (The Age: Oct 2006)

There are more than a hundred failed "climate" predictions listed at WUWT - here.

Why hasn't the MSM examined some of these as sceptical journalists instead of getting into bed with the failed alarmists. MSM - FAIL!

Back to Tony Thomas and the Quadrant article:

But a new blog entrant is specialising in the genre and, by sorting and classifying, turns the scare-a-minute soothsaying into spectacular entertainment.

This new  blog "Climate Change Predictions" is specialising in (laughing at) "climate" predictions.

Take this one page:

hardest hit (by Global Warming)

• Rural Australians will be the hardest hit;
• Sydney’s urban areas to be hit hardest;
• The effects of climate change will impact more severely on the economy of Papua New Guinea than on any other in the Pacific;
• Research reports that Bangladesh is one of the hardest hit nations by the impacts of climate change;
• Africa will be the hardest hit or most affected region;
• Vietnam is likely to be among the countries hardest hit by climate change;
• The Small Island Developing States are among the hardest hit by climate change;
• Maldives economy hardest hit by climate change;
• climate change is likely to have the strongest impact on Scandinavian countries;
• Bulgaria, Spain, Portugal, Italy and Greece are the countries that would be worst affected by global warming, according to a European Union report;
• Climate change is faster and more severe in the Arctic than in most of the rest of the world;
• China’s Poor Farmers Hit Hardest by Climate Change;
• Middle East, African Countries to Be Hardest Hit by Climate Change.

To see that August "Climate Scientists" and bodies who made these conflicting statements go to hardest hit.

Tony Thomas concludes: 

Googling “hardest hit by climate change” is endless fun. For example, cuddly koalas, those really-cute Clownfish and pretty staghorn corals are all going to be “hardest hit by climate change”. For some reason, redback spiders, warthogs and piranhas never make the cut as top climate-threatened species. 

But that’s an article for another day.

Just one more point.

There has been a "pause" in the Global Warming. Many have tried to explain why, although CO2 keeps increasing in the atmosphere, there has been NO global warming for more than 18 years. One of the explanations is by warmist (and false science emitter [said warming was 03ºC when it was a mere 0.03ºC]) Dr Karl: (link) Global Warming: Oceans hide the heat.

That's one reason, Dr Karl. Scientists have been stuttering and spluttering and so far have come up with at least 66 (sometimes conflicting) excuses for the lack of warming.

Sixty Six!  See Hockey Shtick HERE.  The First Ten listed below:

1) Low solar activity 

2) Oceans ate the global warming [debunked] [debunked] [debunked]

3) Chinese coal use [debunked]

4) Montreal Protocol 

5) What ‘pause’? [debunked] [debunked] [debunked] [debunked]

6) Volcanic aerosols [debunked]

7) Stratospheric Water Vapor 

8) Faster Pacific trade winds [debunked]

9) Stadium Waves

10) ‘Coincidence!’ For the next 56 go to Hockey Shtick HERE.

Sixty Six Different reasons.

From the so-called "climate scientist."

When the cruel hoax on humanity is finally exposed, these people will be left without their government grants and out looking for employment. Who would want to employ a scientist who had been involved in promoting a despicable hoax that wasted billions, billions that could have been used for the benefit of humanity?