Climate change doubled the likelihood of the Australian heatwave

February 16, 2017 by Sarah Perkins-Kirkpatrick, Andrew King And Matthew Hale, The Conversation
Maximum temperature anomalies across NSW on February 11, the peak of the heatwave. Credit: Bureau of Meteorology, Author provided

The heatwave that engulfed southeastern Australia at the end of last week has seen heat records continue to tumble like Jenga blocks.

On Saturday February 11, as New South Wales suffered through the 's peak, temperatures soared to 47℃ in Richmond, 50km northwest of Sydney, while 87 fires raged across the state amid catastrophic fire conditions.

On that day, most of NSW experienced temperatures at least 12℃ above normal for this time of year. In White Cliffs, the overnight minimum was 34.2℃, a new record for the state's highest observed minimum temperature.

On Friday, the average maximum temperature right across NSW hit 42.4℃, beating the previous February record of 42.0℃. The new record stood for all of 24 hours before it was smashed again on Saturday, as the whole state averaged 44.0℃ at its peak. At this time, NSW was the hottest place on Earth.

A degree or two here or there might not sound like much, but to put it in cricketing parlance, those temperature records are the equivalent of a modern test batsman retiring with an average of over 100 – the feat of outdoing Don Bradman's fabled 99.94 would undoubtedly be front-page news.

And still the records continue to fall. Mungindi, on the border of NSW and Queensland, broke the Australian record of 50 days in a row above 35℃, set just four years ago at Bourke Airport, with the new record now at 52 days.

Meanwhile, two days after that sweltering Saturday we woke to find the fires ignited during the heatwave still cutting a swathe of destruction, with the small town of Uarbry, east of Dunedoo, all but burned to the ground.

This is all the more noteworthy when we consider that the El Niño of 2015-16 is long gone and the conditions that ordinarily influence our weather are firmly in neutral. This means we should expect average, not sweltering, temperatures.

Since Christmas, much of eastern Australia has been in a flux of extreme temperatures. This increased frequency of heatwaves shows a strong trend in observations, which is set to continue as the on the climate deepens.

It is all part of a rapid warming trend that over the past decade has seen new heat records in Australia outnumber new cold records by 12 to 1.

Let's be clear, this is not natural. Climate scientists have long been saying that we would feel the impacts of human-caused climate change in heat records first, before noticing the upward swing in average temperatures (although that is happening too). This heatwave is simply the latest example.

What's more, in just a few decades' time, summer conditions like these will be felt across the whole country regularly.

Attributing the heat

The useful thing scientifically about heatwaves is that we can estimate the role that climate change plays in these individual events. This is a relatively new field known as "event attribution", which has grown and improved significantly over the past decade.

Using the Weather@Home climate model, we looked at the role of human-induced climate change in this latest heatwave, as we have for other events before.

We compared the likelihood of such a heatwave in model simulations that factor in human greenhouse gas emissions, compared with simulations in which there is no such human influence. Since 2017 has only just begun, we used model runs representing 2014, which was similarly an El Niño-neutral year, while also experiencing similar levels of human influence on the climate.

Based on this analysis, we found that heatwaves at least as hot as this one are now twice as likely to occur. In the current climate, a heatwave of this severity and extent occurs, on average, once every 120 years, so is still quite rare. However, without human-induced climate change, this heatwave would only occur once every 240 years.

In other words, the waiting time for the recent east Australian heatwave has halved. As climate change worsens in the coming decades, the waiting time will reduce even further.

Our results show very clearly the influence of on this heatwave event. They tell us that what we saw last weekend is a taste of what our future will bring, unless humans can rapidly and deeply cut our greenhouse emissions.

Our increasingly fragile electricity networks will struggle to cope, as the threat of rolling blackouts across NSW showed. It is worth noting that the large number of rooftop solar panels in NSW may have helped to avert such a crisis this time around.

Our hospital emergency departments also feel the added stress of heat waves. When an estimated 374 people died from the heatwave that preceded the Black Saturday bushfires the Victorian Institute of Forensic Medicine resorted to storing bodies in hospitals, universities and funeral parlours. The Victorian heatwave of January 2014 saw 167 more deaths than expected, along with significant increases in emergency department presentations and ambulance callouts.

Infrastructure breaks down during heatwaves, as we saw in 2009 when railway lines buckled under the extreme conditions, stranding thousands of commuters. It can also strain Australia's beloved sporting events, as the 2014 Australian Open showed.

These impacts have led state governments and other bodies to investigate heatwave management strategies, while our colleagues at the Bureau of Meteorology have developed a heatwave forecast service for Australia.

These are likely to be just the beginning of strategies needed to combat heatwaves, with conditions currently regarded as extreme set to be the "new normal" by the 2030s. With the ramifications of extreme weather clear to everyone who experienced this heatwave, there is no better time to talk about how we can ready ourselves.

We urgently need to discuss the health and economic impacts of heatwaves, and how we are going to cope with more of them in the future.

Explore further: We've learned a lot about heatwaves but we're still just warming up

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FactsReallyMatter
1 / 5 (9) Feb 16, 2017
So I guess this is one of those selected regional effects which is indicative of global warming.

"Our increasingly fragile electricity networks will struggle to cope, as the threat of rolling blackouts across NSW showed. It is worth noting that the large number of rooftop solar panels in NSW may have helped to avert such a crisis this time around."

What a load of BS! Reading this one would be forgiven for assuming that coal failed the population and renewables saved the day. In reality, it was the renewable sector that caused the damage. Go google the numerous articles on the topic.
gkam
2.3 / 5 (6) Feb 16, 2017
Coal IS failing us, and killing us with its failure. It fails to provide clean power, stunting us instead with toxins in the air.

We do not need it.
FactsReallyMatter
1 / 5 (10) Feb 16, 2017
No, you may need not it. Stop projecting your needs, wants, and dreams, whatever, onto the rest of the world. Solar does not work everywhere, wind does not work everywhere. So you are fat dumb and happy with your fantasy power supply. Great! That simply won't work for everyone. Why does your smugness get to force the majority of the planet into energy poverty?

CO2 is NOT pollution, it is not killing us.
antialias_physorg
5 / 5 (7) Feb 16, 2017
So I guess this is one of those selected regional effects which is indicative of global warming.

Since this is a long lasting trend - yes. as quite plainly noted in this part
"It is all part of a rapid warming trend that over the past decade has seen new heat records in Australia outnumber new cold records by 12 to 1."


What a load of BS! Reading this one would be forgiven for assuming that coal failed the population and renewables saved the day.

Do you even know how coal powerplants work? I know you failed math and chemistry as evinced in other threads. Now it's basic physics. Hint: Carnot cycle. Try to figure out out what happens if the heat differential drops (because the input water is warmer). Hint: steam driven powerplants get less efficient. This goes for coal, gas and nuclear (nuclear additionally gets even less efficient because the cooling gets less efficient)

FactsReallyMatter
1 / 5 (6) Feb 16, 2017
So, are you saying that a trend over a decade is due to AGW?

gkam
1.8 / 5 (5) Feb 16, 2017
"Facts", is going to get a rude wake-up. My system is not special, nor is it fantasy. It is real and it is practical, and it saved me $3,000 last year. You may not live where solar PV makes as much sense, but there are resources around you which you do not recognize.

Where do you live? I'll check it out for you.
snoosebaum
1 / 5 (3) Feb 16, 2017
bit of fun, go to this site and compare highest temps to highest temps from various time periods for sydney aus.

http://www.bom.go...o/cvg/av
antialias_physorg
4.3 / 5 (6) Feb 16, 2017
So, are you saying that a trend over a decade is due to AGW?

The trend is much longer than that.

So are you going to say something in your defense? I mean: it's pretty hilarious that a guy who defends fossil fuels doesn't even know how they work. How did you ever expect anyone would take you seriously?
If this is really what the american school system produces then I can fully understand that only 48% think global warming is man made (a figure pretty singular to the US). I knew it was bad - but that it is THAT bad, that's scary. (Explains Trump, tho)
Captain Stumpy
4.4 / 5 (7) Feb 16, 2017
CO2 is NOT pollution, it is not killing us.
@facts
you make this claim because, in your opinion, CO2 is necesarry for plant life
however, this then must be true of all things necesarry for life, if that is factual, and it is not

case in point: iodine
iodine is vital to your life - so you can make the claim that it is not a pollutant
however, excessive iodine will most definitely kill you, so it is a pollutant when it is found in excessive amounts in the environment
- would you eat a fish that contains excessive iodine?
no

so why then do you not recognize that excessive CO2 is a pollutant?
it's not like this is a guess: for every study that shows CO2 is beneficial to plants, i can then produce studies showing that excessive CO2 is harmful to plants

this has been done multiple times on this site alone - so if you want to argue that it is not a pollutant: show the science

and then we'll talk about the refuting evidence (science)
FactsReallyMatter
1 / 5 (9) Feb 17, 2017
Pretty much anything in excess will kill you.
That doesn't make it a pollutant. Trying to argue that it does shows an absolute lack of knowledge and logic.

Which, of course, explains your faith.
Captain Stumpy
3.4 / 5 (5) Feb 17, 2017
Pretty much anything in excess will kill you.
That doesn't make it a pollutant
@FRM
actually, it does: per the law in the US anyway
Trying to argue that it does shows an absolute lack of knowledge and logic
really?
Definition of pollutant for English Language Learners

: a substance that makes land, water, air, etc., dirty and not safe or suitable to use : something that causes pollution
https://www.merri...ollutant

so, the dictionary states you're wrong
what does the law state? (start with 40 CFR)
Holy [multiple expletives deleted] - it uses the same definition!

but wait! there is logic in science, so what does science say?
http://www.scienc...98001410

they say the same thing (that is just representative of the whole -see:https://scholar.g...dt=0%2C4 )

so, logic would dictate you're biased and arguing from emotion, not facts
Captain Stumpy
3.7 / 5 (6) Feb 17, 2017
@FRM cont'd
Pretty much anything in excess will kill you.
That doesn't make it a pollutant. Trying to argue that it does shows an absolute lack of knowledge and logic.
moreover, you have not produced one shred of actual evidence to demonstrate otherwise, either

so, you make the claim that anything in excess isn't a pollutant (or pollution)
now produce your factual evidence based argument to demonstrate this

now, consider that source material is important, so provide the following:
dictionary examples
legal examples
scientific examples

all from reputable sources and all in refute of my above evidence

that is how "knowledge and logic work - not just because you "say so"
but because you can prove it's true

none of which you've been able to do on PO at all, in any argument against AGW, CO2 or warming

if you want to be an echo chamber for some idiotic belief - that is your choice
but science is about evidence and you aint got none - making you the idiot here
FactsReallyMatter
1 / 5 (4) Feb 20, 2017
Drink 30 litres of water in an hour. Tell me how that goes?
Guy_Underbridge
5 / 5 (4) Feb 20, 2017
Drink 30 litres of water in an hour. Tell me how that goes?

FRM can't see the truth for all the damn facts in the way...
unrealone1
1 / 5 (3) Feb 23, 2017
Snow in Tasmania, snow in Victoria, no mention?
Australia produces 1.2 % of the worlds CO2 but that controls the weather in Australia?
Ojorf
3 / 5 (6) Feb 24, 2017
Australia produces 1.2 % of the worlds CO2 but that controls the weather in Australia?


We are talking about climate, not weather, but yeah, we all wished that it worked that way (it does not) and that every countries emissions & pollutants only affected that country (it does not, no explanation needed).
SamB
1 / 5 (2) Feb 24, 2017
Australia produces 1.2 % of the worlds CO2 but that controls the weather in Australia?


We are talking about climate, not weather, but yeah, we all wished that it worked that way (it does not) and that every countries emissions & pollutants only affected that country (it does not, no explanation needed).

No, we are talking about weather. This article is trying to link the weather to climate change. (Something that has always been denied by the church)
RealityCheck
3 / 5 (2) Feb 24, 2017
Hi FactsReallyMatter. :)

Yes, facts really DO matter. That's why you should get ALL the facts; and CONNECT their interrelationships to discover the NET outcome based on ALL those interconnect facts. :)

Your fixation 'piecemeal' on 'isolated' facts will never 'connect the dots/facts'. It's the TREND in TRANSITION that hurts; and that's what ALL the 'connected facts' are telling us.

Eg, Unseasonal events/extremes of 'weather' are a DIRECTLY connect SYMPTOM of global warming. and while the natural buffers/sinks are still being 'used up' by the warming dynamics, it will warm at a slow pace; but when said buffer/sink systems no longer ameliorate the warming, it will ACCELERATE beyond natural cycles/patterns we and our agriculture and infrastructure was ever design for. The costs and casualties will be ever more extreme, incessant and unrecoverable...and it's beginning to appear NOW in many parts of the globe (Australia being a "canary in the Coal Mine" to show that trend. :)
RealityCheck
3 / 5 (2) Feb 24, 2017
Hi unrealone1. :)
Snow in Tasmania, snow in Victoria, no mention?
Australia produces 1.2 % of the worlds CO2 but that controls the weather in Australia?
AS I explained to antigoracle long ago: Increasing heat energy going into the dynamics will cause greater/faster 'churn' than previously (like a pot of water boiling more vigorously when heat turned up). That explains unseasonal snow/ice storms which hit Tasmania/Victoria...because the ANTARCTIC air masses, which usually travel more SLOWLY across the warmer ocean waters and pick up more heat, are NOW being driven more quickly across said waters, and hence LESS 'dwell time' in which to absorb heat from ocean; and so will be COLDER air mass hitting Tasmania/Victoria more forcefully than when less AGW heat resulted in less churn/speed of atmospheric masses.

There are many examples of unseasonal/unpredictable weather 'patterns/cycles' all over the globe where arctic/antarctic air masses move differently NOW. Cheers. :)

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