Archive for the ‘heatwaves’ Category

Another ABC Fail

February 5, 2017

Viewers of ABC-TV news, and followers of ABC News Online, were treated to a story on Friday night about “Turtle hatchlings dying in extreme heat at Mon Repos”, as it was headlined at ABC News Online:

Piles of dead turtle hatchlings are lining Queensland’s famous Mon Repos beach amid a heatwave which has pushed the sand’s temperature to a record 75 degrees Celsius.

While the majority of hatchlings break free from their nests at night when the sand is cooler, those escaping in the day face overheating.

“They can’t sweat, they can’t pant, so they’ve got no mechanism for cooling,” Department of Environment and Heritage Protection chief scientist Dr Col Limpus said.


The extreme heat is also conducted down to the turtle’s nest, pushing the temperature to about 34C, which is approaching the lethal level for incubation.

That is the hottest temperature recorded in a nest in more than a decade.

A record 75 degrees sand temperature? Hottest nest temperature in more than a decade?

Time for a reality check.

I have no data on temperatures inside turtle nests, but I do have data on temperature at nearby Bundaberg Aero (Hinkler Airport), which is an ACORN site.

Using monthly Acorn data, here is a plot of all January maxima at Bundy.


January’s mean maximum of 31.6 degrees C was equalled or exceeded in 1924, 1931, 1969, 1998, 2002, 2006, 2013, and 2014.  While monthly mean doesn’t tell us about individual days, it does give us a clue about daily temperatures in hot years.  For that I also use ACORN daily data- adjusted, homogenised, and world’s best practice apparently.

How do temperatures at this time of year compare with those of previous years?  The next figures show data for the first 45 days of every year, that is from January 1 to February 14.


The past three weeks at Bundaberg have been at the high end of the range, but no records have been broken, and no days have been even close to 35C.  What about previous years?  The next plot shows the number of consecutive days above 35 degrees: very likely to raise sand temperature above what it has been this year.


No days this year above 35C, but at least 27 occasions in previous years of single days reaching 35C, at least 6 of 2 days in a row, and one of 3 days in a row above 35C.

A 7 day running mean will show whether temperatures have been consistently high.


As you can see 2017 is high but not extreme.  2002 had a 7 day average just under 35C.

This graph plots temperatures of the first 45 days of years with similarly hot January temperatures.  2017 is the thick black line.


On one day- January 20- 2017 was hotter than the other years.  Note how in several years the temperature drops to the mid 20s when heavy rain falls.  Note also the temperature reached the high 30s in February 2002.

The final graph shows the 7 day average of the same period of similarly hot years.


Several previous periods were hotter than so far this year.

Once again we see misleading claims being made and reported by the ABC as gospel, without any attempt at fact checking.  A simple check shows that, while it may be true that the reported temperatures are the hottest recorded by these researchers, it is extremely unlikely that these were as high as they were in past years.  On every count- daily, monthly mean, 7 day mean, consecutive hot days- it can be shown that this year, while hot, is not as hot as many previously, and it follows that sand temperatures would similarly have been hotter in the past.

And that’s without considering the Holocene Optimum and the Eemian.

Another ABC fail.

Putting Temperature in Context: Pt 2

December 14, 2016

To show how handy my Excel worksheet is, here’s one I did in the last 15 minutes.

Apparently Sydney has had its warmest December minimum on record at 27.1 C.  The record before that was Christmas Day, 1868 at 26.3C.

The following seven plots show this in context.

Fig. 1:  The annual range in Sydney’s minima:


Extremes in minima can occur any time between October and March.

Fig. 2:  The first 2 weeks of December


Plainly, a new record was set this morning, but apart from Day 340 the other days are within the normal range.

Fig. 3:  7 day mean of Tmin in this period


Extreme, but a number of previous years had warmer averages.

Fig. 4:  Consecutive days above 20C Tmin.


But there have been longer periods of warm minima in the past.

Now let’s look at the same metric, but for all of December.

Fig. 5:  All Decembers (including leap years).


A record for December, with 1868 in second place.

Fig. 6:  7 day mean of Tmin for Decembers


Seven day periods of warm nights are not new.  The horizontal black line shows the average to this morning (20.6C) is matched or exceeded by a dozen other Decembers.  (Of course this December isn’t half way through yet.)  Also note what appears to be a step change about 1970.

Fig. 7:  Consecutive days above 20C Tmin in December.


I doubt if 15 December will be as warm as today, but could still be over 20C.

This is weather, not global warming.


Putting Daily Temperature in Context

December 14, 2016

In this post I demonstrate a simple way of comparing current temperatures for a particular location with those previously recorded.  In this way it is possible to show the climatic context.

Using data from Climate Data Online, I plot maximum temperature for each day of the year, and then for a particular short period: in this case the last week of November and the first week of December, which coincides with the recent very warm spell here in Queensland.  To account for leap and ordinary years this period is 15 days.  In ordinary years 24th November is Day 328 and 7th December is Day 341, while in leap years this same calendar period is Day 329 to 342.  I also calculate the running 7 day mean TMax for this period, and the number of consecutive days above 35C.

To put the recent heatwave in context, I have chosen six locations from Central and Southern Queensland which regularly feature on ABC-TV weather: Birdsville, Charleville, Roma, Longreach, Ipswich (Amberley RAAF), and Rockhampton.


Fig. 1


The Police Station data are from 1954 to 2005, and the Airport from 2000.  This shows the range of temperatures throughout the year.  The red arrow indicates the current period.   The next plot shows data only for the period in question.

Fig. 2:  24 November- 7 December: Airport data


Note there were three days where the temperature this year was the highest for those days since 2000, but didn’t exceed the highest in this time period, which was in November.  The other days were well within the historic range.

For interest, let’s now see how this year compares with the Police Station record.  (The average difference in TMax during the overlap period was 0.0 to 0.3C.)

Fig. 3:  24 November- 7 December: Police Station data


In a similar range.

Fig. 4


This heatwave was the third hottest since 2000 and fifth overall.

Fig. 5


Five previous periods had more consecutive days above 35C.  2006 had 22.


Fig. 6: Charleville Aero since 1942


Temperatures in this period reached the extremes of the range on three days.

(Although the Post Office record begins in 1889, there are too many errors in the overlap period so the two records can’t be compared.)

Fig. 7:


A new record for early December was set, but note this was the same temperature as 29th November 2006.

Fig. 8:


Definitely the hottest for this period since 1942.

Fig. 9:


Note this was not the longest warm spell by a mile: there were many previous periods with up to 26 consecutive days above 35C.


Fig. 10:


Although there is not one day of overlap so the two records can’t be compared, you can see that Airport (from 1992) and Post Office records are similar.

Fig. 11:


A new record for this time of year was set: 44.4C, and six days in a row above 40C.  Pretty hot….

Fig. 12:


…but there were longer hot periods in the past (since 1992).


Fig. 13:  Longreach Aero since 1966.


Fig. 14:


Hot, but no record.

Although there is good overlap with the Post Office, temperatures for this period differ too much: from -1 to +0.7C.

Fig. 15:


Fifth hottest period since 1966.

Fig. 16:


And in the past there have been up to 47 consecutive days above 35C at this time of year.

Ipswich (Amberley RAAF):

Fig. 17:


Fig. 18:


Not unusually hot for this time of year.

Fig. 19:


Ninth hottest since 1941.

Fig. 20:


Hotter for longer in the past.


Fig. 21:


Fig. 22:


Very hot, but no records.  (The heat lasted another two days, with 36.6 and 37.3 on 8th and 9th.)

Fig. 23:


Fourth hottest 7 day average on record (since 1939).

Fig. 24:


Again, a number of hot days, but there were as many and more in the past.

To conclude: the recent heatwave was very hot certainly, and was extreme in southern inland Queensland.  While Charleville had the highest seven day mean temperature on record, NO location had as many consecutive hot days (above 35C) as in the past.

This is a handy method for showing daily data in context.  It can used for any period of the year, can be tuned to suit (I chose TMax above 35C, but temperatures below a set figure could be found), and can be used for any daily data.

If you would like a comparison done for a location that interests you, let me know in comments including time period and parameters of interest (e.g. Sydney, first 2 weeks of December, TMax above 30C say, or Wangaratta, September, daily rainfall over 10mm say.)

Temperature and Mortality

May 24, 2016

We are all going to die, nothing is surer. “Nobody knows the day or the hour”, but one thing is clear: we are more likely to die in winter than in summer.

Death by unnatural causes (suicide, accident, bushfire, disaster, even acute illness) can come to otherwise healthy people of any age. Death by natural causes is more predictable.

Those vulnerable to death are the elderly, very young babies, those with chronic illness (e.g. asthma, diabetes) and weakened immunity, and those with respiratory and circulatory illness.

Analysing mortality is made difficult because the sample population is always changing. Excess deaths in one month may be followed by further excess deaths in the following month, or because so many vulnerable people have already died, there will be fewer than expected deaths in the next month or months, or even the next couple of winters. Similarly, if fewer than expected deaths occur, there will be a larger cohort of the vulnerable in the following months, getting older and with probably poorer health. Population growth, aging, migration, improved vaccines, and public education programs all play a part as well.

In this analysis, I use mortality and population data from the Australian Bureau of Statistics (ABS), and temperature data from the Bureau of Meteorology (BOM), for Victoria, as it is a small and compact state which is subject to large temperature changes and also severe heat waves. Monthly mortality data are difficult to find, so this study is restricted to the period January 2002 to December 2011. A 10 year period is hardly sufficient for meaningful averages, however some useful insights can be found.

Mortality statistics are available by month, but population figures are by quarter, therefore I interpolated estimated monthly population figures based on three month growth.

Firstly, this plot shows the total deaths for every month from January 2002 to December 2011.

Fig. 1:

act D per mnth
Note the seasonal spikes and dips. The apparent increase in deaths can be compared with Victoria’s population increase:


Population Vic
By dividing the total deaths by the population in thousands we can calculate the death rate:

Fig. 3:

Death rate per yr

Note the mortality rate has decreased, and that, in spite of heatwaves, bushfires, and flu pandemics, 2009 had a lower death rate than 2008.

Because months have varying numbers of days, a better analysis can be made by calculating the Daily Death Rate for each month (by dividing each monthly rate by 31, 30, 29, or 28 days).

Fig. 4:

mortality per month

For the state of Victoria for the 10 years to 2011, on average more deaths occurred for each day in August than for any other month. The lowest Daily Death Rate was in February.

Now compare with monthly averages (2002 to 2011) for maximum and minimum temperatures:

Fig. 5:

Tmax Tmin avg

The death rate peak lags July temperature by about a month. Cooler months (June to September) are deadlier than warmer (December to April).

The relationship with temperature can be shown with scatter plots:

Fig. 6:

DDR v Tmax

Fig. 7:

DDR v Tmin

Which merely reinforce that deaths are more likely in winter!

Now we look at the question of estimating how many deaths are likely in a given period, by multiplying the average daily death rate for each month by the number of days in each month and by the estimated total population for each month. By subtracting this figure from the actual number of deaths we get a mortality “anomaly”.  The following graph shows this anomaly for each year:

Fig. 8:

Act minus exp deaths per year

And each month:

Fig. 9:

Diff act minus exp Deaths per mnth

Note the peaks in the winters of 2002 and 2003, and also in the summer of 2008-2009. Note also that both graphs show that in spite of a killer heatwave, the Black Saturday bushfire, and the swine flu pandemic, deaths in 2009 were below what could be expected.

To put the anomaly for January 2009 into context, we can compare actual daily deaths per 1,000 population for all months from 2002 to 2011:

Fig. 10:

act daily D per mnth

Note that the extreme figure for January 2009, while extremely high for January, is still below those of the lowest extremes of June, July, and August.

Perhaps higher mortality in the winter months is coincidence and due to some other factor than temperature- seasonal flu incidence for example. I now look at the month of August with the highest average mortality rate:

Fig. 11:

Act minus exp deaths vs Tmin August

There is fairly decent correlation showing that for every degree warmer in minima, the August death toll will be around 150 less than expected.

February, with the lowest rate:

Fig. 12:

Act minus exp deaths vs Tmin Feb

Even in summer, warmer minima mean fewer deaths.

In summer, do higher maxima cause more deaths?

Fig. 13:

Act minus exp deaths vs Tmax Feb

Even including the 173 deaths in the Black Saturday bushfires in the 200 extra deaths for February 2009, there is no trend.

January, whose data include the 2009 heatwave:

Fig. 14:

Act minus exp deaths vs Tmax Jan

A very small trend, but the 2009 heatwave outlier is obvious and skews the data. (Victorian health authorities say there were 374 excess deaths in the week to 1 February 2009).

Extreme heatwaves are indeed killers. Normal hot summers up to two degrees above average are not.


Improved public health measures, influenza vaccines, and improved public awareness – plus warmer winters- have led to a decrease in the Victorian mortality rate in the period 2002-2011.

Extreme heatwaves are dangerous in Victoria and cause hundreds of extra deaths especially amongst the elderly (>75 years old). However, these are rare events. Severe and Extreme Heatwaves are newsworthy precisely because they are unusual.

Normal Victorian winters are even more dangerous with on average 17.5% more deaths in winter than summer every year, but because this is normal and expected, this regular annual spike in deaths is unremarkable and not newsworthy- much less regarded as a natural disaster. While 374 excess deaths in a week in a heatwave is shocking, even with these included, the highest January’s Daily Death Rate (in 2009) is below that of the lowest of any winter month.

Warmer minimum temperatures are associated with lower death rates at all times of the year, but especially in August in Victoria, where for every degree of extra warmth, about 150 fewer deaths can be expected. I hope, for the sake of those who are sick or elderly, that we have a warm winter this year.

Heatwaves: From One Extreme To Another

August 8, 2015

When Is A Heatwave Not A Heatwave?

When the Bureau of Meteorology defines it out of existence.

In his reply to me on behalf of Dr Vertessy, Bob Baldwin wrote:

“The Bureau has adopted a particular operational heatwave definition motivated by human health considerations, defined as a period of at least three days where the combined effect of high temperatures and excess heat is unusual within the local climate.  ……….The bulk of heatwaves at each location are low intensity with local communities expected to have adequate adaptation strategies for this level of thermal stress.  Less frequent, higher intensity heatwaves are classified as severe and will challenge some adaptation strategies, especially for vulnerable sectors such as the aged or the chronically ill.”

After some digging, I found this paper which describes the Bureau’s methodology used in their Pilot Heatwave Forecast:

The Excess Heat Factor: A Metric for Heatwave Intensity and Its Use in Classifying Heatwave Severity, John R. Nairn and Robert J. B. Fawcett (2015)

The method is quite easy to follow and implement, and I was able to replicate results for the 2014 Melbourne heatwave exactly and use it successfully for other single locations.   It is designed for use with AWAP gridded data of course to give forecast maps.  Note this is raw data, not homogenised.  I downloaded all data from Climate Data Online.

There are several steps.  Readers should read the paper for full details.  Briefly, using a daily mean temperature calculated by averaging the day’s maximum and the following night’s minimum, three-day means are calculated.  These are then compared by subtracting the previous 30 days’ daily means (as people acclimatise to changed temperatures in this period).  Differences that exceed the 95th percentile of all three-day means from 1971 to 2000 are multiplied by the three-day mean to give the Excess Heat Factor, which indicates heatwave.  This is then compared with the 85th percentile of all positive EHFs from 1958 to 2011 to give a severity index, and if it exceeds 3 times the 85th percentile this becomes an extreme heatwave event.

From the paper:

The intent of these definitions is to create a heatwave intensity index and classification scheme which is relative to the local climate. Such an approach is clearly necessary given the abundant evidence that people and supporting infrastructure are largely adapted to the local climate, in physiology, culture and engineered supporting infrastructure.”

Here are the results for Melbourne- with all its UHI effect of course.

Fig. 1: Decadal (running 3653 day) count of positive Excess Heat Factor (heatwave) days in Melbourne

Decadal cnt pos EHF days Melbourne

Fig.2: Decadal count of Severe Heatwave Days

Decadal cnt severe HW days Melbourne

Fig.3:  Decadal Count of Extreme Heatwave Days

Decadal cnt extreme HW days Melbourne

Notice how Melbourne heatwaves of all types have been increasing and extreme events are currently at the highest level “ever”.

How does this apply to various other Australian locations?  I decided to check with the extremes- the hottest and the coldest Australian locations, Marble Bar in the north west of W.A. and Mawson Base in Australia’s Antarctic Territory.

Fig. 4:


The old Marble Bar station closed in 2006.  I have concatenated the old Marble Bar data with the new, from 2003. This makes very little difference to the calculations but extends the record to the present.

Fig. 5: As for Melbourne, decadal count of heatwave days

pos EHF days marble bar 2

Fig. 6:  Severe heatwaves

count severe HW days marble bar 2

Fig. 7:

count  extreme HW days marble bar 2

It is clear that local climate does make a big difference to heatwaves by this definition.  In fact, Melbourne has more extreme heatwave days than Marble Bar!

How does this method of detecting and measuring heatwaves deal with Marble Bar’s record heatwave of 1923-24?

According to the Australian Government’s website, Disaster Resilience Education for Schools at

“Marble Bar in Western Australia holds the record for the longest number of hot days in a row: the temperature was above 37.8°C for 160 days in 1923-24.”

I count 158 days consecutively from daily data at Climate Data Online.  The total for the 1923-24 summer from 13 October to 19 April was 174 days.  That is indeed a long period of very hot weather.

Surprisingly, the BOM does not class that as a long or extreme heatwave.  Apparently, according to this metric, there were only four short heatwaves, one of them severe, and none extreme.  For the entire period, there was only one severe heatwave day – 3 February.

Fig. 8:  Marble Bar 1923-24 summer.  I have marked in the old “ton”, 100 F, or 37.8C.  Squint hard to see the “severe’ heatwave around 3 February, but the heatwave around 22 February is invisible to the naked eye.

EHF Marb Bar 1923 1924 2

Yes, the old timers at Marble Bar were pretty tough and would be used to hot conditions.  But not to recognise this old record heatwave when every day in over five months was considerably above body temperature is laughable.

For comparison, Figure 9 shows 182 day counts of days that were over 100 degrees Fahrenheit, or 37.8 degrees Celsius.  (The old record finishes in 2006.)

Fig. 9:  Running 182 day counts of days over 100 F.  1923-24 is circled.

Days 100F Marb Bar

Note there were two other years when there were more than 170 days over 100F.

Figure 10 is from Figure 16 in the Nairn and Fawcett paper, and is a map of the level of Excess Heat Factor across Australia during the heatwave of January-February 2009.

Fig. 10:  Figure 16 from Nairn and Fawcett (2014)- Excess Heat levels across Australia 21 January – 11 February 2009.

Fig16 from paper max ehf 2009

The area around Marble Bar has a level of between 0 and 10.  My calculations show this is correct- EHF reached 0.08 on 23 January- a mild heatwave.  Readers may be interested to know that maximum temperature was above 40 degrees Celsius from 1 January to 24 January, and minima were not below 24.3.

The authors, and their employer, the Bureau, are in effect telling Marble Bar locals their heatwaves don’t rate because they’re used to the heat.

Now I shall turn to the other extreme- Mawson.

Firstly, plots of the range of minima for each day of the year:

Fig. 11:  Scatterplot of minima for each day of the year at Mawson Base

minima v day Mawson

Fig. 12: maxima:

maxima v day Mawson

Fig. 13:  Decadal count (running 3653 day count) of days with positive Excess Heat Factor, i.e., by definition, heatwave days

Decadal cnt pos EHF days Mawson

Fig. 14:  Decadal count of days in severe heatwave:

Decadal cnt severe HW days Mawson

Fig. 15:  Decadal count of days in Extreme heatwave:

Decadal cnt extreme HW days Mawson

Apparently, Antarctica gets more extreme heatwave days than Melbourne, or Marble Bar!

Of course, critics will say this metric was never intended for use in Antarctica, and I agree: no one would seriously claim there are heatwaves there.  However, if heatwaves are to be defined as “a period of at least three days where the combined effect of high temperatures and excess heat is unusual within the local climate”, and NOT by comparison with any absolute threshold, then this analysis of its use there is valid.  “High” temperature by this definition is relative to the local climate, wherever “local” is. If this metric fails in Antarctica, it fails everywhere.


The Bureau of Meteorology’s metric for heatwaves is a joke.  It may accurately detect heatwaves in the southern fringe of Australia, and a further use may be to support Dr Vertessy’s outlandish claims.  However, it fails to cope with different climates, particularly extremes.  A methodology that fails to detect heatwaves at Marble Bar, and creates them in Antarctica, is worse than useless- it is dangerous.

After 15 Weeks, the Bureau Responds With Non-Answers

July 16, 2015

On 30 March 2015, in response to some “interesting” claims made on ABC Radio by Dr Bob Vertessy, the head of the Bureau, I sent by the normal feedback channel four questions, summarised below:

Q.1: Can you please supply me with a reference to your data that show that the number one cause of death is heatwave?

Q.2:  Can you please supply me with a reference to your data that show five times as many very serious heatwaves today compared with the middle of last century?  Could you also please tell me your criteria for a very serious heatwave.

Q.3:  In what way can 38.9%, 36%, or 34.1% difference in quadratic change (between trends of the supposedly “raw” Australian Water Availability Project data and those of the ACORN-SAT dataset) be interpreted as “no difference”, “exactly the same story”, or “the same result”?

Q.4:  When can we expect to see the results of this further work (monthly and seasonal analysis of differences between AWAP and ACORN) published on the ACORN-SAT website?  If it is available elsewhere please refer me to it.  I am particularly interested in any difference in quadratic change in summer maxima between AWAP and ACORN-SAT, as this is relevant to heatwave analysis.

I followed up with reminder queries on 28 April, with an email to Bob Baldwin (the Parliamentary Secretary responsible for this farce the Bureau) on 1 May, a Formal Complaint on 18 May, another email query to him on 15 June, and phone calls to his office on 25 June and 10 July.  In this last phone call I mentioned that I would approach the Opposition Environment Shadow Minister (Mark Butler) if I didn’t get a reply soon.

A reply was emailed to me on Tuesday 14 July.

Unfortunately, Baldwin’s reply contains no straight answers, avoids answering questions, gives misleading answers, contradicts itself, makes debateable interpretations, has at least two links to references that are not valid, and makes no apology or explanation for the delay.

Here is the full text of Baldwin’s reply, emailed on Tuesday 14 July, followed by my comments.

“I refer to your email of 1 May 2015, concerning an email sent to the Bureau of Meteorology’s Queensland Regional Office regarding an ABC radio interview with the Director of Meteorology.

As I am sure you can appreciate, the Bureau deals with a number of important issues in the interests of the public, including many severe weather events across the country.  As such, the Bureau does not always have the capacity to provide detailed and tailored responses to the many individual enquiries they receive.  I have, however, requested that the Bureau provide a full explanation to the four questions you raised in your email dated 30 March 2015.  The responses are below:

1.  Heatwaves kill more Australians than any other natural disaster.  As outlined in Coates et al (2014), from 1844 to 2010, extreme heat events have been responsible for at least 5,332 fatalities in Australia, and since 1900, 4,555: more than the combined total of deaths from all other natural hazards.  Refer:

-Coates, L., K. Haynes, J. O’Brien, J. McAneny and F.D. De Oliviera (2014)Exploring 167 years of vulnerability. An examination of extreme heat events in Australia 1844-2010. Environmental Science & Policy, 42, 33-44, doi:10.1016/j.envsci.2014.05.003.


-Queensland University of Technology (2010) Impacts and adaptation response of infrastructure and communities to heatwaves: the southern Australian experience of 2009, report for the National Climate Change Adaptation Research Facility, Gold Coast, Australia.


2.  The duration, frequency and intensity of heatwaves have increased across many parts of Australia, based on daily temperature records since 1950, from when coverage is sufficient for heatwave analysis.  Days where extreme heat is widespread across the continent have become more common in the past twenty years.  Refer:

-Perkins, S.E., L.V. Alexander and J.R. Nairn (2012) Increasing frequency, intensity and duration of observed global heatwaves and warm spells.  Geophys. Res. Let.., 39, L20714, doi:10.1029/2012GL053361.


-Perkins, S.E., (2015) A review on the scientific understanding of heatwaves- their measurement, driving mechanisms, and changes at the global scale.  Journal of Atmospheric Research, submitted.

There are many valid ways to characterise discrete heatwaves and warm spells.  The Bureau has adopted a particular operational heatwave definition motivated by human health considerations, defined as a period of at least three days where the combined effect of high temperatures and excess heat is unusual within the local climate.  This does not preclude the use of other heatwave indices suitable for various research questions.  The bulk of heatwaves at each location are low intensity with local communities expected to have adequate adaptation strategies for this level of thermal stress.  Less frequent, higher intensity heatwaves are classified as severe and will challenge some adaptation strategies, especially for vulnerable sectors such as the aged or the chronically ill.  Refer:

-Perkins, S.E. and L.V. Alexander (2013) On the Measurement of Heat Waves, J. Climate, Vol. 26, No. 13, pp.4500-4517. Doi: 10.1175/JCLI-D-12-00383.1)


-Bureau of Meteorology Pilot Heatwave Forecast:

3.  As shown in the figure below, both adjusted and unadjusted temperatures show that Australia’s climate has warmed since 1910.  Most of this warming has occurred since 1955, when adjusted and unadjusted data are virtually identical.

BOM awap-acorn graphic

4.The Bureau continues to monitor and research Australian temperatures.  This work is ongoing, and not being conducted as part of a specific project.  Therefore, the work is undertaken as resources allow, and not subject to specific milestones and timelines.  However, all significant research will be published and made available in the scientific literature following its completion and peer review.

The Bureau of Meteorology puts a great deal of time and effort into producing research and services around climate variability and change.  The Bureau shares observations daily with the world and its research is peer reviewed and published in high quality international journals for everyone to see.

Noting the wide public availability of scientifically robust climate data and information, I encourage you to seek answers to questions through the publicly available information, such as the references provided above.  The Bureau can provide any further analysis and response on a cost-recovery basis, in line with Australian Government Cost Recovery Guidelines.

Thank you for writing on this matter.

Yours sincerely

Bob Baldwin”


There is no mention of my Formal Complaint, just my first email to Baldwin’s office.

There is no apology, and no explanation for the delay in replying by either the Bureau or Baldwin.

Response to Question 1: 

Why doesn’t Dr Vertessy just admit he may have misled listeners by not specifying that heatwaves are the number one cause of death “in natural disasters”?

Coates et al do indeed show that heatwave deaths exceed those of other natural disasters since 1844.

Figure 1:   From Coates et al (2014)- heat related deaths 1844-2010 (click to enlarge)

Coates graph

However, they clearly show that the number of deaths (and much more so, the death rate) was consistently much higher in the first 75 years of last century than the past 40 years, and while the 2009 heatwave certainly caused a spike in the number of deaths, the mortality rate per 100,000 was eclipsed by the 1896 heatwave, as well as 1908 and 1939, and also 1910, 1912, 1914, and 1927.  It appears from this graphic alone that “very serious heatwaves” were more common in the past than recently.

Figure 2 shows the average daily death rate per 1,000 for Australia from 2002 to 2012 taken from Australian Bureau of Statistics data (monthly death rate divided by the number of days in each month).  It is clear that mortality peaks in late winter, and is lowest in summer (December – April).

Figure 2: Daily Mortality Rate per 1,000 Population, 2002 – 2012

Daily mortality

Unfortunately, cold spells are not recognised as natural disasters, as they occur every year.  Deaths from cold are not limited to hypothermia, or burial under snow, or crashes on slippery roads, or house fires caused by heaters.  Every winter the death rate rises significantly as the sick and elderly succumb to chronic cardio-pulmonary illness, influenza, and pneumonia.  Cold is the real “silent killer”.

Response to Question 2:

Notice how my question, specifically querying five times as many very serious heatwaves today compared with the middle of last century, which is what Dr Vertessy claimed, has been neatly avoided.  The Bureau merely states that heatwaves “have increased”.  Dr Vertessy’s outlandish claim cannot be substantiated.

After quoting Coates et al in answer to the previous question, the Bureau now claims heatwaves can only be analysed since 1950.  If that is so, we can ignore the 70% of all heatwave deaths that occurred between 1900 and 1949, as only 1,378 heat related deaths occurred between 1950 and 2010 (see Figure 1 above).  While exact figures are not available to me, it would be interesting to see the total for floods, cyclones, bushfires, storms, tornadoes, earthquakes and landslides for this period, and whether 1,378 heat related deaths exceeds this.  Does the Bureau not see this contradiction?

Further, Perkins et al (2012) finds increased heatwave trends in percentage of days per season are “confined to… southern Australia”, not “many parts of Australia” as claimed in Baldwin’s reply, which is therefore misleading.  The claim that “days where extreme heat is widespread across the continent have become more common in the past twenty years” is not supported by evidence in this reply, as the second Perkins paper referenced is not yet published.  True or not, this is irrelevant.

Unfortunately, the link to the third Perkins paper does not work.  The Bureau’s Heatwave Forecast appears to be based on a similar metric to that used by Nairn and Fawcett (2015) in calculating an Excess Heat Factor to identify and predict heatwaves.  This at least will be useful.

Response to Question 3:

Again, the Bureau has chosen to avoid answering my question, clinging to their meme of warming since 1910, which I did not dispute, and that the difference between AWAP and ACORN since 1955 is negligible, which also I did not dispute.  My question was whether this negligible difference was evident from 1911, which the Bureau’s own paper (CTR-050) shows to be false.

Response to Question 4:

A short answer to my query would have been “No”.  No analysis of the difference between AWAP and ACORN on a monthly or seasonal basis has been undertaken.  Apparently I am the only person to have done this, and my results showing massive differences in maxima trends, largely due to just two adjustments, have not been falsified.

The final paragraph of Baldwin’s reply could be paraphrased as “Don’t ask us any more awkward questions.  If you do, you can expect to pay for the privilege of waiting three months to get a non-answer”.

Dr Vertessy has failed to substantiate his claims.  After 15 weeks, the Bureau has been forced to make a reply, which avoids answering questions, gives misleading answers, contradicts itself, makes debateable interpretations, has at least two links to references that are not valid, and makes no apology or explanation for the delay.  Thankfully, it does give references to some papers that give some information on heatwave detection.

What a farce.  I am disappointed, but not surprised.

However, I do think Dr Vertessy’s forays into the media world will be much more carefully scripted in future.