Posts Tagged ‘Antarctic temperatures’

BBC Accused of Misleading Reporting About Melting Antarctic Glacier

January 30, 2020

Every morning I get these annoying “click bait” pop-ups on my phone, which I usually ignore. This morning I weakened, and tapped the headline:

Antarctica Melting: Climate change and the journey to the “doomsday glacier”.

Knowing a bit about Antarctica, I dismissed it as more BBC rubbish, but just a few minutes ago I received a message from the Institute of Public Affairs with a link to a press release and article by the Global Warming Policy Forum. Here it is in full:

Press Release 29/01/20
 
BBC Accused of Misleading Reporting About Melting Antarctic Glacier
 
Why did the BBC fail to mention the volcanoes underneath?

London, 29 January: The Global Warming Policy Forum has criticised the BBC for misleading the public about the melting of the Thwaites Glacier.
 
In its numerous reports online, on radio and on television, the BBC blamed the melting of this Antarctic glacier on climate change. However, the BBC’s reports do not mention an important fact that has been widely known and that the BBC itself has reported previously – the influence of volcanoes beneath the glacier.
 
Scientists have known for years that subglacial volcanoes and other geothermal “hotspots” underneath the glacier are contributing to the melting of the Thwaites Glacier.

“Despite claims about climate change and admonition to lower our greenhouse gas emission as a way to ameliorate the melting of Thwaites, the BBC should have been pointing out that what is happening underneath the glacier could be in large parts an act of geology and one of those natural and globally-important dynamics that have been occurring throughout the ages,” said GWPF science editor Dr David Whitehouse.

What is more, the scientists will remain on Thwaites for a while. They have not analysed their data yet, so claims that they have confirmed “the Thwaites glacier is melting even faster than scientists thought…” are premature.

…..

More information about the Thwaites Glacier and the BBC’s misleading reporting can be found on the GWPF website.

I have long suspected that any warming in Antarctica might be due to the large volcanic province beneath West Antarctica, when UAH satellite temperatures show no sign of Antarctic warming, as I have shown here.

I’m pleased the GWPF is onto it so quickly, and many thanks to the IPA for alerting me.

Global Warming in Antarctica

August 10, 2015

Global Warming is supposed to have greater effect in polar regions, but for some time the apparent refusal of the South Polar region to comply has been of some interest.  Sea ice area increase can be explained away by various mechanisms, but actual temperatures are more difficult to explain.

Using UAH V6.0 data, here is the graph of the Temperature of the Lower Troposphere (TLT) for the South Polar Region, below 60 degrees South, since satellite records began in December 1978.

SPolar

For as long as we have records, Antarctica has not warmed at all.  The trend is -0.04 degrees Celsius (+/- 0.1C) per 100 years.  Zero trend, (or slightly cooling if you want to annoy your Global Warming Enthusiast colleagues).

Enjoy!

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:

Map

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

https://schools.aemi.edu.au/heatwave/real-life-heatwave-stories

“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.

Conclusion:

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.

Call that a Pause?

May 13, 2015

The length of the “pause”, “hiatus”, slowdown”, or “plateau”, whatever you wish to call it, is of great interest to sceptics and mainstream climate scientists alike, although Global Warming Enthusiasts such as John Cook try to pretend it doesn’t exist and/or is not important.

In this post I am showing the length of time during which the linear trend of temperatures is less than +0.01C per 100 years- i.e. zero or negative.  I use the UAH version 6 data to April 2015 which has been recently released, for various regions of the globe.  University of Alabama (Huntsville) data are derived from satellite radiosonde data for the lower troposphere.  These represent how the bulk of the atmosphere is behaving.

I am well aware of the criticism that commencing the trend calculation near the 1997-1998 El Nino may distort the trend, so these calculations merely show how far in the past we can go to find a zero or negative trend.  (In a future post I intend to exclude the big lump of data around this period for an alternative look at trends.)  In several of these plots there is very little discernible bulge around 1997-1998 at all, so I consider the trends are valid.

Firstly, how long is the pause globally?

Fig. 1:  Global data with zero trend (less than +0.01C/100 years) (Click to enlarge)

uah pause apr 15 globe

This includes the 1997-98 El Nino which may distort the trend calculation.  However, see several plots below which don’t show this effect.

Fig. 2:   North Polar (60 degrees North to 90 degrees North)

uah pause apr 15 npol

Despite claims to the contrary, during this admittedly short period the Arctic has not been warming.

Fig. 3:  Northern Hemisphere (Equator to 90 Degrees North)

uah pause apr 15 NH

Only slightly shorter than for the whole globe. Trend= +0.007C/100 years.

Fig. 4:  Southern Hemisphere (Equator to 90 degrees South)

uah pause apr 15 SH

This includes three years before the 1997-98 El Nino.  The trend is +0.006C/100 years.

Fig. 5: Tropics (20 degrees North to 20 degrees South)

uah pause apr 15 Tropics

The tropics include the Tropical Pacific where ENSO events are identified, and the pause extends well before the super El Nino.

Now you’ve heard that Antarctic sea ice is expanding to new records, but of course this is due to, variously, stronger katabatic winds and/or melt water filling the gaps and freezing over- all due to global warming naturally.  But you may have a suspicion that the Antarctic region is not actually warming as much as global warming enthusiasts would have you believe.  Has there been a pause in Antarctica?

Fig. 6:  South Polar region (below 60 degrees South)

uah pause apr 15 spol

Now that’s a Pause!

I also checked pause length for Australia and the USA.

Fig. 7: Australia

uah pause apr 15 aus

There does not appear to be an unusually large spike during 1997-98.

What about our North American cousins?

Fig. 8: Contiguous USA

uah pause apr 15 usa48

The effects of the 1997-98 El Nino do not have a large influence here either.

Note to Global Warming Enthusiasts: The Pause is real!  Build a bridge and get over it!

What did Chris Turney expect?

January 5, 2014

Professor Turney did not have to take an unsuitable ship full of “climate tourists” to Antarctica.  He could have just checked the Bureau of Meteorology’s website.

As the Aurora Australis will be calling at Casey base to deliver delayed supplies before returning the hapless Turney and the rest of the expedition to Australia, I thought I’d help with what conditions to expect at Casey.  I used official ACORN-SAT monthly data to 2011 and Climate Data Online daily temperatures since then.

Here are the actual monthly maximum temperatures at Casey for 2013:Casey max 2013

As you can see, temperatures were below the mean (calculated from 1970-1990) for most of the year, and the monthly mean maximum temperatures were above freezing (the straight blue line) only in January and December.  Monthly mean minimum temperatures never get above freezing.   (The highest daily minimum in 2013 was +1.7 C on 15 January.  The warmest minima this summer were on 29 and 30 December.  It got to +0.3.)

And has there been recent warming?

This graph is of maximum and minimum anomalies from the 1970-1990 means, smoothed with running 12 month means:Casey 1970-2013

Australia has three bases on the Antarctic coast, Casey, Davis, and Mawson.  Davis and Mawson show some slight warming:Davis 1958-2013Mawson 1958-2013

The mean anomalies of all three sites:Antarctic means

show a linear trend of about  +0.15 C- but the rise (such as it is)  is by no means steady.

To show how insignificant the warming is in Antarctica, here are annual mean anomalies compared with those of Australia:Antarctic-Oz comp

Remember, one of the so-called “fingerprints of greenhouse warming” is that warming should be greater towards the poles.

Professor Turney could have saved himself a lot of time, trouble, and embarrassment.