More angry, more often: March heatwave signals a new normal

From The Conversation, more on Australia’s record breaking “Angry” summer: enjoy! 

By Sophie Lewis, University of Melbourne and Sarah Perkins

Daylight hours are dwindling and our first month of autumn is ending. But in many places, March felt a lot like summer. Get used to it: looking ahead, all indications are that future summers could be just like this one, or more extreme.

Southeast Australia welcomed autumn with a persistent heat wave. For the first 12 days of autumn, temperatures were 6.9 degrees above normal across Tasmania and 6.8 degrees above normal in Victoria.

Melbourne’s March record-breaking weather included nine days of temperatures of 32 degrees or above and its hottest overnight March temperature in 110 years of record keeping. Adelaide experienced ten such hot days.

The unusually warm autumn weather was part of a much larger and much longer warm spell. The last six months have been characterised by sequences of heat waves and record temperatures across the entire Australian region.

Summer was the hottest on record across all of Australia. In January, Australia had its hottest month on record. The hottest day ever recorded for the entire continent occurred on January 7.

The surrounding oceans, from the Great Australian Bight through Bass Strait, also broke previous extreme temperature records. These waters exhibited the hottest sea surface temperatures on record in February.

Our exceptionally hot summer cannot be discussed simply as a catalogue of interesting record-breaking events. This summer was not normal. And we can’t talk about the exceptionally hot summer and early autumn without talking about climate change.

Australian average temperatures have increased faster than the global average increase (0.8°C) and are now 0.9 degrees warmer than a century ago.

It may not sound like much, but research shows that changes in average temperatures (even less than 1°C) can lead to huge changes in the frequency and severity of extreme climate events.

This is exactly what Australia just experienced with this sequence of heat waves, extending from November 2012 to March 2013.

Our recent research in the internationally peer-reviewed Journal of Climate shows that there has been a significant increase in the number of heat wave days for most of the country from 1951-2008. The paper describes heat waves as a period of three or more days where temperatures are excessively hot – in the top five to 10% of temperatures recorded.

This trend is greatest in eastern Australia, where both the number of heat waves and their duration has increased.

Recently, we extended the time period of the analyses to include the period from 1911 to 2011. Not surprisingly, our initial results suggest that heat waves are now occurring earlier than 100 years ago. In some places, the first heat wave of the season is occurring almost a month earlier.

Recent studies from other parts of the world have shown that many, if not most, of the recent record-breaking heat waves and extremely warm summers would have been unlikely to occur without human influence on climate change.

Although we can never say categorically whether an individual climate event, such as a heat wave, would have occurred without human-related greenhouse gas emissions, it is possible to assess how global warming has changed the likelihood of extreme events occurring.

Working with other climate scientists we investigated the probability of extreme summer heat occurring across Australia using a suite of climate model simulations representing current climate conditions. We then used a parallel suite of control experiments, in which greenhouse gases from human activities were entirely absent.

Previous studies using similar methods have found strong human contributions to the severity of extreme summer temperatures. James Hansen and other NASA scientists found a 10-fold increase in areas experiencing extremely hot summers due to global warming. Similarly, climate scientist Gareth Jones and his colleagues at the UK Met Office Hadley Centre found a dominant human influence on rapidly increasing hot summers in the Northern Hemisphere.

When we ran our hot, angry summer through a large group of the latest generation of climate models it became clear that there was likely to have been a substantial human influence on our recent extreme summer heat. Our early results indicate that anthropogenic climate change more than tripled the risk of Australia’s extremely hot summer occurring.

As for the future, it is now virtually certain that the frequency and severity of hot days will increase. Extremely hot seasons will worsen, with the biggest impacts of climate change being felt by Australians in summer. Spring weather will come earlier, and autumn later.

Additional global warming over the next 50 years, under a business-as-usual fossil fuel emissions scenario, is expected to see global average temperatures increase by at least 1°C. Such a change means that our recent summer on steroids will become the norm and far worse summers will occur with greater frequency.

We already know what is causing the changes we see now. Clearly, it is time to stop talking about record-breaking heat as isolated incidents and recognise them in the context of climate change.

It’s time to start preparing for more angry summers, more frequently.

Sophie Lewis receives funding from the Australian Research Council.

Sarah Perkins is a research associate at the UNSW node of the ARC Centre of Excellence for Climate System Science.

The Conversation

This article was originally published at The Conversation.
Read the original article.

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65 thoughts on “More angry, more often: March heatwave signals a new normal

  1. Eric Worrall says:

    Interestingly, the Northern Hemisphere is suffering a pretty seriously “Angry” winter, with abnormal cold and snow. Britain still hasn’t melted, which is very unusual, considering its almost April.

    The following article discusses the severe impact the severe cold is having on agriculture:-

    If a first world country like Britain is suffering massive livestock losses, because they can’t keep their livestock warm and fed, what is happening in poorer places like Russia?

    Perhaps the Southern hemisphere will be able to make up the difference, but if the trend to colder winters in the North continues, as we approach Little Ice Age conditions, we could be seeing the start of a new food crisis.

    And that should worry anyone living in Australia – China, with its enormous military and economic capacity, is taking serious livestock losses as well, due to the abnormally cold and snowy conditions.

    Meanwhile, we fritter away our economic capacity tackling the non-problem of “global warming”.

    • john byatt says:

      very much the same argument as the creationist leon Ashby in last weeks paper

      my reply went in saturday

      The old proverb “A lie is halfway round the world before the truth has got its boots on” is a fact of life as the likes of Leon Ashby (The Gympie Times March 20) continue to parrot the verballing of IPCC chief Rajendra Pachauri by The Australian newspaper. The irony is that while misrepresenting Pachauri and misinforming the Australian public, The Australian has the audacity to present their absurd distortion as free speech and the freedom of the press in action, yet refuse to publish Pachauri’s letter to the editor correcting their own nonsense.

      The Arctic seasonal sea ice will be hard pressed to last the next two years let alone the next decade. The rate of global warming has now exceeded anything for the past 100,000 years. In claiming no warming, Ashby has completely lost touch with reality. The past decade was the warmest decade since records began, yet only a few days ago Leon Ashby’s own political party’s blog proclaims that “ we have now entered a mini ice age” apparently his only evidence is two days of snow in the U.S. In the immortal words of john McEnroe, “you cannot be serious”

      “Dire predictions that the planet would fry and drown” ,by 2013 Mr. Ashby? You are most likely confusing science with one of your own evidence based religious videos.

    • Nick says:

      Hmmm. Eric takes the crank Corbyn at face value [heading for a LIA],and ignores the discussion from arctic meteorology experts about the effect of sea ice thinning and loss on the behavior of the atmosphere above and around the poles. Why would he prefer decree rather than explanation?

      Corbyn releases ‘commandments’ of breathless fudging in an impossibly jumbled pdf . No work is shown,magic solar intercession is cited,no models are used,no stats crunched. Corbyn will not release his methodology. Spends a lot of his time dismissing meterology in order to sell his weather service. Classic authoritarian decree.

      Meteorology has given detailed mechanistic explanation,and the physical background – amplification of global warming effects will be seen at polar and near polar latitudes – was first proposed from physical principles back in the 1970s,and subsequently observed over the following decades. We have plenty of papers tracking the weakening of the polar vortex inducing wandering weak jet streams and increasing blocking events which can heighten warm and cold events. Eric has had the ‘cold enough to snow does not mean very cold’ mechanism explained to him before,and just ignores it. He cannot conceive of a system that can warm over time,while showing more heightened variation on the way

      Evidently none of this appeals to Eric,because it lacks the Corbynesque shrillness.

    • zoot says:

      Following Erric’s link I now find “the Northern Hemisphere” consists of North Wales.

    • uknowispeaksense says:

      So we can now add the ‘yellow peril’ to your list of stupid ideas. I’m beginning to wonder where xenophobia fits in conservative think and how it correlates with religiosity and denial? First you use them as a scapegoat and now you try and drum up fear of their “enormous military”. You’re as bad as Scott Morrison wanting to treat asylum seekers like pedophiles in that you are appealing to the bottom of the intellectual barrel.

    • Eric Worrall says:

      I’m not saying China is a threat – for a leading world economic power they have shown a remarkable level of restraint in military affairs. What I am saying is if global cooling triggers a food shortage, they might get desperate.

      There is a good possibility that global cooling will not trigger a food shortage. Even if food production is damaged in the North, farm productivity is far higher now than it was during the LIA. Synthetic fertiliser and genetic engineering. has drastically raised productivity, and if necessary we have the capacity to mass produce plastic for large scale greenhouses, and enough fossil fuel energy or nuclear power to keep them warm.

      But as the solar cycle approaches Maunder minimum levels of activity, things could get very cold for a few decades. Grain fields in Canada and Russia could stop producing anything at all, and many other growing areas could suffer shorter, less hospitable growing seasons.

      On reflection, if there is a Northern food shortage, America could be the real threat – they have a far more interventionist track record, and a much bigger military than China. If America is hungry, Australia might find itself pressured into signing a few disadvantageous “treaties”, to ship large quantities of food to America. Australia buckling to pressure to sign disadvantageous treaties with America is hardly an unprecedented event.

      • zoot says:

        I’m not saying China is a threat – for a leading world economic power they have shown a remarkable level of restraint in military affairs. What I am saying is if global cooling triggers a food shortage, they might get desperate.

        I’m not saying China is a threat. But if they run short of food they will be a threat.
        Have I parsed it accurately Erric?

      • john byatt says:

        whereas if the US runs short of food they will quietly starve to death and leave us alone.

        this is a poe i take it

      • Eric Worrall says:

        whereas if the US runs short of food they will quietly starve to death and leave us alone.

        In my second comment I suggested the US is possibly a more serious threat, if they go hungry – that Australia might be coerced into signing disadvantageous treaties. After all, Australia has rolled over and played good doggie before when the US snapped its fingers.

        When I thought of who might starve, my first thought was China, because it has a lot of poor people who live on marginal farmland in the freezing North. But the US could also suffer severe food shortages, especially if there is a large influx of refugees from Canada, and w/r to recent history they have a more aggressive military track record than China.

        I’m not saying China is a threat. But if they run short of food they will be a threat.

        Anyone who runs short of food is a threat. The question is which neighbours might suffer most from a drop in global temperatures, and who of those who would suffer have the capability to do something about it.

        Of course, if Australia expands food production capacity enough to more than compensate for losses elsewhere, as I indicated might be possible, then everyone else might be content to simply buy a bit more food to cover their needs.

        But cold periods historically are also dry periods – so southern hemisphere food production might actually go down, which worst case might mean there is not enough food to feed everyone.

        The question of who starves to death might be settled by warfare.

    • Global warming presages a food shortage. Look at yields from last year’s American heat wave.

      Who are you fooling with your nonsensical global cooling?

    • Steve says:

      Don’t worry Eric, global cooling is much easier and cheaper to reverse than global warming.
      The problem is that the world is warming rapidly.

    • Joel says:

      Actually, although this has been a very cold March over here in the UK, these sorts of cold Marches did happen quite a bit back a few decades ago. It’s unusual, and difficult to manage, because this sort of thing hasn’t happened… in a while. Indeed, this March merely gets us back to the sorts of lows seen in the 60s, whereas last March, for example, was a record high.
      Average for this March to date is 2.5 degrees.

      • john byatt says:

        coldest march in 50 years UK met , warm arctic cold continents

      • Nick says:

        March has been anomalously cold over northern Europe and Siberia,while anomalous warmth has sat over Greenland and the Canadian Archipelago. The Arctic atmospheric stability is buggered by mechanisms which have been linked and discussed here already. The hemispheric average is normal,it’s the regional picture which has become unstable.

    • astrostevo says:

      @Eric Worrell :

      “Interestingly, the Northern Hemisphere is suffering a pretty seriously “Angry” winter, with abnormal cold and snow. Britain still hasn’t melted, which is very unusual, considering its almost April.”

      Yeesh mate. Do you know what the word ‘average’ means?

      Say we have 8 places with far hotter than usual temperatures and two with cooler than usual ones. What do you think that makes the average?

      Now you said the “northern hemisphere” is abnormally cold of late – *if* that were true what would you expect would be happening with Arctic sea ice? Would it be growing, shrinking or stable?

      Now there’s a site called the National Snow & Ice Data centre that tels you what’s been happening – its right here :

      Take a look and tell me – what exactly does it look like the sea ice is doing and is that at all consistent with your idea of a “northern hemisphere” that’s abnormally cold or not?

  2. mase says:

    Good aticle, but I’ll get in the cherry – pick before Andrew Bolt does

    “we can never say categorically whether an individual climate event, such as a heat wave, would have occurred without human-related greenhouse gas emissions”

    see, even the experts beleive that the Earth is cooling.

    Denialism 4 lyfe!

  3. john byatt says:

    Those climate sceptics at geoff browns blog had me rolling around slapping my thighs in laughter

    They are incredible comedians

    by taking Tim Flannery’s name, removing nnery, then add an M at the end, precede it with Flim, then you can convince yourself that Tim is not honest

    how brilliant is that?

  4. john byatt says:

    eric corbyn ” we are heading into an ice age”

    the climate sceptics party ” we have just gone into a little ice age”

    Monckton “By digging up and burning fossil fuels, humans are releasing carbon that had been buried in the Earth into the atmosphere, helping to stave off the mass extinctions that would follow from the next – and long overdue – Ice Age”

    better bring monckton up to date on the latest .

    • Eric Worrall says:

      Two different events, the big one, which is due anytime in the next 8000 years, and the little one, which is likely to be triggered by the approaching lull in solar activity.

      Or are you one of the solar minima deniers, who believes the Maunder, Dalton, etc minima coinciding with periods of extreme cold is just a coincidence?

      • zoot says:

        That would be the little ice age that is indicated by the three hottest decades on record, continued loss of Arctic ice and the continued retreat of the glaciers as solar activity has declined.
        Of course! It all makes perfect sense (if you worship at the Watts Tabernacle – haven’t they got a lovely choir?).

      • john byatt says:

        Yes it would make a big difference eric


        • uknowispeaksense says:

          Since I just moved from albury to the gold coast, I am now regretting giving my thermals to charity. If eric gets his way im going to need them next year when we are plunged into the next ice age.

      • Eric Worrall says:

        I doubt S/E Queensland will get that cold – but I’m not taking chances.

        My wife and I are looking at some places in the far North, for our next residence.

      • Citations for your nonsense are always appreciated. Which journals discuss the implication of Maunder, Dalton and Sporer over the last few decades? I sense a deniar clutching at straws.

      • zoot says:

        My wife and I are looking at some places in the far North, for our next residence.

        I’ve already found just the place – Marble Bar. In fact I know of a house there that I would be happy to rent for you for 6 months (can’t get it until October unfortunately). It’s quite cheap because it doesn’t have air conditioning, but it’s got every other mod con including high speed internet access, so a hotshot IT contractor like you would be able to telecommute. Just say the word Erric, and remember I’m paying the rent for the first six months.

      • Eric Worrall says:

        Hmm, interesting:-,_Western_Australia

        The town set a world record of most consecutive days of 100 °F (40 °C) or above, during a period of 160 days from 31 October 1923 to 7 April 1924.

        Still, lets not get too excited by a single event ;-).

        RE your kind offer, thanks but I don’t think we’ll take it. I like gold prospecting areas, but it looks a little isolated. I was thinking somewhere in the Highlands – nice and green, lovely warm weather all year round. But I’ve never been there, so early days.

      • zoot says:


      • Yeah, why get excited by whole continents? No one really cares about them anyway.

      • I take it, Eric, that you couldn’t find any supporting citations in response to my challenge. No surprise – another Worrall fact-free assertion.

        Citations for your nonsense are always appreciated. Which journals discuss the implication of Maunder, Dalton and Sporer over the last few decades? I sense a deniar clutching at straws.

      • zoot says:

        I was thinking somewhere in the Highlands – nice and green, lovely warm weather all year round.

        So it’s warm weather you want, not hot weather (which is going to be the lot of your grandchildren).

  5. The prediction is more extremes. More heat -and- more cold, drier where it’s already dry, wetter where it’s already wet. The European cold, whilst unusual, is not record setting – and is due to the jet stream changing due to the arctic melting – due to ACC.

    If climate were as simple as Worall we’d have one season.

    • Eric Worrall says:

      I don’t think you missed anything. Essentially you’re suggesting any change is validation of your theory, and proof that its all our fault.

      • Essentially you’re demonstrating that you are a zealot. More extremes is a prediction – and one that is being born out. Your incredulity is not disproof.

        Every week there’s a new Worrall “AGW is dead, I knew it!” meme. And then, no, the science proves you wrong every time.

        When you look al -all- the evidence the answer is clear. It’s CO2 and us.

      • Eric Worrall says:

        Essentially you’re demonstrating you are anti-science. You are predicting anything unusual which happens is validation of your theory – any unusual event is cited by you as “proof” that dangerous anthropogenic global warming climate change is real.

        To see how silly this is, try inverting your prediction. If more extremes is evidence of global warming, would abnormally uneventful weather evidence of global cooling? Or is abnormally uneventful weather simply more evidence of our impact on nature?

      • You’ve just jumped a shark. The science makes predictions you can’t invalidate and you cry foul. More predictable, cooler, weather would invalidate ACC. That’s not happening.

      • Ah yes, that new-fangled “climate change” expression. The one popularised by a Bush II strategist, Fred Luntz. Now, let’s see, the IPCC was formed in 1988. Take your time, Worall, no pressure – what do you think the “CC” stands for in this 25 year old organisation? No pressure. Proof, again, that the IPCC is inherently over-conservative.

    • roymustard says:

      This is interesting – an article from last year: “Arctic sea ice melt ‘may bring harsh winter to Europe’

      “The jet stream is clearly weaker,” said Francis. That means weather systems, be it rain or dry conditions, are slow to move on and last longer. Ultimately this can result in “blocking” events, such as the conditions that produced the terrible heatwave in western Russia during the summer of 2010, she said.

      This summer, Greenland experienced a similar blocking anti-cyclone, resulting in a record surface melting of its ice sheet. It is not possible to directly connect that block to the prolonged US heatwave and drought this summer, Francis said. However “blocks act like a traffic jam, slowing down weather patterns elsewhere”.

      These changes are happening much earlier than scientists thought, said James Overland, an oceanographer and researcher at the University of Washington.

      “We’ve only had a little bit of global warming so far,” Overland said.

      As the sea ice continues to decline, the jet stream will likely continue to slow more, and shift further north “bringing wild temperature swings and greater numbers of extreme events” in the future he said. “We’re in uncharted territory.”

  6. “… it is possible to assess how global warming has changed the likelihood of extreme events occurring.”

    “… it is very clear that warming has been dominated by increased carbon dioxide levels.”
    “A warmer planet means a warmer atmosphere for all our weather and climate.”


    But what are the implications of this?
    How former warming influence on heat waves?

    About this tells us (even relatively recent) past.
    At the time of the old warming the number of heat waves (and their extremity) is always decreasing. “… the higher latitude continents north of 50N in both periods [max. Eemian, mid-Holocene] were much warmer than present-day climate in winter, not so much warmer in summer. “Climate models don’t do this. „… they are generally too warm on summer …”

    In all likelihood, we can say that the past – former warming – greater than the current, is mainly much warmer winter, but not summer, it does not increase or decrease in the number of heat waves.


    Most likely “per” cool (relatively – without extreme heat waves) summers during the past strong warming, are responsible aerosols and clouds (increasing humidity of the atmosphere towards declines the pressure gradient – the dominance of shallow low pressure systems). “From around 150,000 to 130,000 years ago, North America experienced colder and generally more arid than present conditions. About 130,000 years ago, a warm phase slightly moister than the present began, and conditions at least as warm as the present lasted until about 115,000 years ago.”

    The current increase of greater and longer heat waves (and the numbers) in Australia is mainly the result ( :
    „The hotter and drier outlook is the result of a weak El Niño combined with abnormal Indian Ocean temperatures.”

    Although I think that (not only the last heat wave in Australia) is the result of a relatively rapid transition to weak La Nina ( + a short term, sharp fall the value of the PDO index (this is most likely, only period of several years – PDO variability we know very little) and positive phase of the AMO. (

  7. Work James Hanson of 2012 (rather Sato and Ruedy – Hanson never lead on this study – only “been added”) as the base period only takes a negative phase of the AMO “50 years ago” – hence the result of 3σ warmer than the climatology of the 1951–1980 – base period for the current heat waves.

    1951-1980 – the “interesting” base period
    The first period (1951-1980) is the decreasing phase of the AMO ( + negative phase of the PDO ( The second period (1981-2010) the increasing phase of the AMO + positive (circa 90%) phase of the PDO.
    Okres bazowy jest więc całkowicie inny (od obecnego okresu) pod względem warunków oscylacyjnych – to oczywiste.

    Rhines i Huybers (2013, )
    the results of the work Sato-Ruedy write this: “… there is no indication that variability about the mean has increased …”

    So this “manipulations” more stringently evaluates L. Motl, poor climate expert – denier, but an outstanding specialist when it comes to statistical analysis
    „ Let me say in advance that the degree of their sloppiness is so spectacular that they should have been kicked out of the college during the first quantitative exam they attempted to face. Today, it’s too late and we must watch how similar mediocre slackers have contaminated – and help to further contaminate – the scientific community.”

    The Met Office Hadley Centre in collaboration with the Walker Institute for Climate System Research , University of Reading (
    “… it is very difficult to do this type of analysis … … so it MAY TAKE MANY YEARS before we could confirm how … … have been altered by greenhouse gases.”

  8. And in Europe and North America is now actually the coldest since 1963, and April may be the coldest since 1815 …


    Probably for the same reasons as today is extremely hot in Australia (+ jet stream), but I would add:

    ( Helama (2010):
    “The observed variations may have occurred in association with internal climate amplification […] (likely, thermohaline circulation and El Niño–Southern Oscillation activity). THE NEAR-CENTENNIAL DELAY in climate in responding to sun spots indicates that the Sun’s influence on climate arising from the current episode of high sunspot numbers may not yet have manifested itself fully in climate trends.”

    ( Swingedouw (2010): “We argue that this lag is due, in the model, to a no rthward shift of the tropical atmospheric convection in the Pacific Ocean, which is maximum more than four decades after the solar forcing increase.”
    “Changes in wind stress, notably due to the NAO, modify the barotropic streamfunction in the Atlantic 50 years after solar variations.”

    ( Varma (2011):
    “Since the reduction in TSI is only 0.15%, the global cooling effect is small and ADDITIONAL FEEDBACKS are required to induce a significant change in the westerlies.”
    “… we propose that THE ROLE OF THE SUN in modifying Southern Hemisphere tropospheric circulation patterns has probably been UNDERESTIMATED in model simulations of past climate change.”

    006264.pdf) Sejrup (2010):
    “The observed ocean temperature response is LARGER than expected based on simple thermodynamic considerations, indicating that there is dynamical response of the high‐latitude ocean to the Sun. […]”
    ( Hu (2003):
    “Our results imply that SMALL VARIATIONS IN SOLAR IRRADIANCE induced PRONOUNCED cyclic changes in northern high-latitude environments.”

    NOAA ( :
    “… our understanding of the indirect effects of changes in solar output and feedbacks in the climate system is minimal […]

  9. sorry…
    The base period is so completely different (from the current period) in terms of the conditions of oscillation – it’s obvious.

    • zoot says:

      Are you saying yes it’s warming but it’s caused by the sun?

      • astrostevo says:

        If that’s what is being said then you need to take a look at :

        Solar Schmolar by Greenman3610 mirror site by Chylde Null.

        Just for starters.

        Our daytime star has been well monitored by NASA and others for many decades and, no, it ain’t the cause of our current Global Overheating.

        Also, how stupid do you think climatologists are that they would overlook something this obvious?

  10. astrostevo says:

    “Adelaide experienced ten such hot days.”

    Actually according to radio 891 ABC news the other week it’s been twelve days over thirty degrees in Adelaide and the average is eight. That was before a day of 36 degrees as well. So we’ve gone from basically an average of one week in March over 30 to nearly half the month.

    • astrostevo says:

      Italics fail, sorry. Only first line was meant to be italicised in my comment above. My apologies and feel free to edit accordingly if you’re willing to do so.

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