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Guardian article: Australia's recent extreme weather isn't so extreme anymore

Posted on 11 February 2011 by John Cook

Over the last week, the Guardian have been running the Green Blog Festival. Over 10 days, they'll feature 10 bloggers from 10 countries. For Australia, they asked me to write an article. I thought about important Australian issues at the moment - Ian Thorpe coming out of retirement, Australia losing the Ashes to England or all the extreme weather we've been having. Hmm, better go with the extreme weather. The article was published yesterday: Australia's recent extreme weather isn't so extreme anymore. Here's an excerpt:

Going by the first six weeks, 2011 has not been a good year to live in Queensland, Australia. In the first fortnight, we experienced heavy downpours, culminating in the south-east floods which killed 22. While we were still mopping up the damage, one of the biggest cyclones in our history hit the north Queensland coast. Cyclone Yasi had grown to a category five by the time it hit landfall. All this and we were barely into February.
You can understand if Queenslanders are feeling somewhat battered at the moment. But we're not the only part of Australia being afflicted by extreme weather.
Flooding has spread to the southern states. To the west, Perth hasn't got off lightly either, threatened with a cyclone last week and currently suffering from bushfires. Sydney just went through a record-breaking heat wave, with temperatures soaring into the mid- to high-30s for seven days running. The longest heat wave since records began in 1858.
When you scroll down the list of extreme weather events, we're ticking a lot of boxes. As an Australian, it can be somewhat disconcerting when climate bloggers from overseas hold up Australia as a harbinger of what's to come for their own countries. It's not fun being climate change's cautionary tale.

Click here to read the rest...

Many thanks to all the SkS authors (and Wendy) for their feedback and suggestions. Interestingly, of all the blog posts so far, it's Joe Romm's and my posts on extreme weather where the comments threads have gone ballistic.

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Comments 1 to 44:

  1. http://www.abc.net.au/science/articles/2011/02/10/3135509.htm

    Australian researchers studying corals off the coast of Queensland have found the frequency of extreme rainfall events has increased over the past 100 years.

    just added that to the coments thread.
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  2. the "click here to read the rest" link don't work
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    Response: Oops, sorry, fixed!
  3. Try this
    http://www.guardian.co.uk/environment/blog/2011/feb/09/australia-extreme-weather-flooding-drought Fixed link [muoncounter]
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  4. Enjoyed the article, John, and the recent change in Guardian moderation policy has improved the discussion to a large extent!

    Cheers - John
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  5. In all these discussions of weather disasters, we should recognize that we realy don't know the limits of what is 'natural' and what is not.

    In the Brisbane flood 2011, the hydrologist who oversaw the planning of Wivenhoe dam was quoted in the 'Australian' thus:

    "When John Oxley discovered Brisbane 180 years ago, the local Aboriginal people were very agitated about flooding and they showed him high water marks that would have been 12m".

    The 1893 floods were just over 8.0m and Brisbane 2011 was 4.5m - and 1974 flood 5.5m.

    Given there are many changes to the population and roads, roofs, surface vegetation since 1824 - however these probably worsen the runoff and increase flood heights.

    On a world wide scale - weather disasters are supposed to be getting worst according to sources like insurers. Well they would say that wouldn't they?? Bigger disaster - bigger premium next time.

    No doubt payouts are getting larger - because areas are more densely populated and properties are much more developed, expensive, complex and larger in advanced countries. More people have insurance due to the explosion in mortgage lending and compulsory insurance, and the documentation of disasters is far better due to satellite pictures, and better communications.

    Anyway - who is going to argue with Aboriginal history about the Brisbane river being naturally subject to a 12m flood?

    I bet not too many of you are game.
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  6. In the Polish press is given very bad information for Australia. Not citing sources, says that: "Australian scientists studying coral reefs - increases over the last 3000 years - they realized that long periods of peace are separated by a few-teenage periods of rapid change. Australia is likely to wait until a few years so violent natural disasters. "

    The fact that the reefs are an excellent "barometer" of climate change in the past, can be found here: Response of coral reefs to climate change: Expansion and demise of the southernmost Pacific coral reef, Woodroffe et al., 2010.
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  7. Ken Lambert #5, insurance is a competetive industry and insurance companies have an interest in getting the risks right. If one company is claiming that climate change is increasing risk and so raise their premiums, another company, if they believe climate change is not occuring, will simply undercut these prices.

    Munich Re's database of weather-related loss events shows a clear rise in these extreme weather events, which they state cannot be explained fully without acknowledging climate change. Increasing population denisity and better reporting also increase the loss, but on their own this is not enough to explain the trend. The trend in non-weather-related losses, such as volcanic events, is not rising in line with weather-related loss.
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  8. #5: "we should recognize that we realy don't know the limits of what is 'natural' and what is not."

    KL actually makes a salient point despite his obvious intent.

    Here is a partial list of what passes for 'natural' these days:

    -- Heat wave in Europe (2010), following the heat waves in 2007, 2006, 2003; models show increasing frequency of future heat waves.
    -- Hundred year drought in the Amazon (2002-2005) followed by 2010's even more severe drought.
    -- Devastating flooding followed immediately by a cat 5 cyclone in Queensland: the largest tropical storm to strike Australia since Europeans first settled there.
    -- Four cat 5 and one cat 4 Atlantic hurricanes in 2005.
    -- Four cat 4 Atlantic hurricanes in 2008.
    -- Extreme precipitation events suggesting an increased frequency of the heaviest events with warming, several times larger than the expected Clausius–Clapeyron scaling

    That our global climate system is changing is undeniable; the limit of what is fast becoming the new natural is what we do not know.
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  9. Arkadiusz Semczyszak, why do you post part of an article (?) from the "Polish press" ? What do you think that adds ?
    It's certainly not connected to the link you do give, so it would be good if you could make clear what you are trying to get across.

    muoncounter, I think it is obvious by now that 'natural' and what can be attributed to 'natural' will be extended by the so-called skeptics as 'natural' becomes less and less 'natural' in the real world. As will the length of time we will supposedly have to wait before thinking about doing anything, just to make sure 'natural' is not possibly measured in hundreds, thousands, hundreds of thousands, even millions of years. I can see it coming : "It could be a natural event on a million-year time-scale ! Prove 100% it isn't !!"
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  10. Great article John,

    I had no idea that you ere doing that until I received me weekly email from the Guardian. yes, quite a few misguided comments, but when I last looked reason and science were persevering. I agree with authors that the improved moderation at The Guardian has helped in keeping the threads focussed and forcing people to speak to the science and not go on ideological rants. they should be commended for that-- because in the past, that is a loophole that the "skeptics" have taken advantage of.

    What people like Ken simply fail to understand is that their repeated claims that what we are witnessing is merely natural variability is a clever distraction, and misses the point. Yes, climate varies, we all know that, especially the climate scientists. But evidence has shown that even in the last 30 years or so the return period for severe events around the globe has been contracting and that there has been a discernible shift towards more extremes. We do not have to breaks records each and every year for there to be problems.

    What Ken et al. also forget is that 200-300 years ago there was practically no infrastructure and there were most definitely not even close to the number of people on the planet that there are today-- so even small shifts beyond what society has developed its infrastructure in can have marked consequences. Before, planning for a one-in hundred year event may have covered the bases, that is not going to be sufficient in the coming decades.

    And as for Australia I encourage people to please read this paper by Gallant and Karoly (2010, J. Climate) in which they conclude:

    "Australian extremes are examined starting from 1911, which is the first time a broad-scale assessment of Australian temperature extremes has been performed prior to 1957. Over the whole country, the results show an increase in the extent of hot and wet extremes and a decrease in the extent of cold and dry extremes annually and during all seasons from 1911 to 2008 at a rate of between 1% and 2% per decade.

    and

    "However, the trends from 1911 to 2008 and from 1957 to 2008 are not consistent with these relationships, providing evidence that the processes causing the interannual variations and those causing the longer-term trends are different."

    Yes, something very different is going on alright.
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  11. #7: "a clear rise in these extreme weather events"

    Isn't it remarkable that the insurance industry is taking the lead in recognizing that things are changing? Similar observations made on the weird weather thread.
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  12. John, Your readers might like to know that we in New Mexico, USA just defeated our Republican governor's nomination of the denier and former astronaut Harrison Schmitt to be head of the NM office of the Environment and Natural Resources Department. I personally wrote two letters to the Santa Fe New Mexican newspaper in support of the withdrawal of his nomination, as did many other New Mexicans.
    In order to not be off-topic, Australia's extreme weather is just a sample of what's to come in the not-too-distant future. We in the SW US just suffered from severe freezing temperatures because of warming at the poles forcing colder weather to the south. One day last week it was 2 degrees warmer at the North Pole than it was in southern New Mexico.
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  13. Good news, rockytom. Seems like he used some privacy concerns to back out before he embarrassed himself and your state any further. Well done.
    Good, also, to see THE GUARDIAN taking control of its Comments policy and not allowing so many of the same repetitive posts regurgitating all the same old wacky denial.
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  14. They may have improved buty there's still a lot of the old crazy denialist rubbish and 'nit-pick-the-story-to death' lines like 'how do you define extreme events...', well you draw a line in the sand and say that those events that exceed it are extreme. If more events occur that are, by definition, extreme then the incidence of extreme events increases - seemples!

    The occurance of extreme events has been noted to have increased. It doesn't matter a damn how to define it, as long as you can make a reasonable statistical comparison between extreme and non-extremme situations.
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  15. A good article which reinforces predictions made by climate science to the effect that global warming will result in greater rainfall in the north of Australia and less in the south where drought conditions may become more prolonged. The global prediction is that extreme weather events will become more extreme and more numerous and, to use the vernacular, You Aint Seen Nothing Yet!

    This prognosis may well have led Sen. Milne and others to express their dismay at government axing of programs aimed at reducing greenhouse gas emissions, in order to fund repair of flood-damaged infrastructure. At the time PM Gillard offered the justification that the sacrificed programs, although highly visible, were an inefficient means of reducing emissions. A more efficient and effective method of curbing would be pursued.

    Julia Gillard is correct. Introduction of cap and trade system or ETS would be far more efficient and far more effective in reducing CO2-e emissions than any of the programs axed by her government. Whether she will introduce an ETS with appropriate safeguards preventing circumvention of its purpose and whether appropriate CO2 reduction targets will be adopted are matters which must be pursued.

    A further matter which must be pursued is the abject failure of government and property owners to learn from the past. In light of the above prognosis, will they yet again rebuild assets on sites prone to destructive flooding and winds without adequately protecting against those elements?
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  16. Albatross at 04:02 AM on 12 February, 2011, regarding the Gallant and Karoly paper you recommended, whenever I see such analysis I always consider how or why the beginning and ending points have been selected as often it becomes apparent that such points often sets a stage that puts a bias on the outcome, especially when considering trends.
    The year 1911 was at the end of 3 consecutive La-Nina years with the IPO (Inter-decadal Pacific Oscillation) in the midst of a relative short negative (wetter) phase, with SOI reaching a value of 16.
    Three longer phases of the IPO subsequently occurred during the 20th century, a positive (dryer) phase (1922-1944), a negative (wetter) phase (1946-1977) and another positive (dryer) phase (1978-1998) with another change of phase in the process of forming since then.

    The year 1957 in the midst of long negative (wetter) phase happened to be an El-Nino year preceded by again 2 consecutive La Nina years during which the SOI value again peaked at about 16.

    Therefore before one can conclude that something very different is going on, other than some short term aberrations, one needs to consider if the beginning and ending points of the study were firstly moved back, say a nominal one decade, and then secondly moved forward one decade, would the same conclusions be reached.

    A matter of further interest regarding the recent floods is that
    PROFESSOR Stewart Franks, a hydrologist at NSW's University of Newcastle, warned in a peer-reviewed scientific article published in 2006 that the risk of serious flooding in southern Queensland and NSW increases significantly when a negative phase of the Interdecadal Pacific Oscillation corresponds with a La Nina event.
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  17. Ken Lambert - there may have been 12m floods in the city reach way back when. But don't underestimate the mitigation effect that Somerset & Wivenhoe dams had. Peak flow was estimated at a bit over 7,000 m3/s past the city gauge. There were reports that inflows to Wivenhoe alone topped 1 million megalitres per day, or close to 12,000 m3/s. And that was at the same time that Somerset was rapidly filling as well, in addition to the floods coming down the Lockyer & Bremer catchments.
    If all that had come down the river at the same time, then a peak around 6 or 7 metres (i.e. 1.5-2.5 metres higher than we got) would have been out of the question.
    And while, yes, there has been additional development over recent decades, that's not where the water was coming from - the land where the rain fell is largely agricultural or, indeed, native forest.
    So I regard this as a fairly extreme rainfall event. Sure, it may not be the most extreme Brisbane has ever had, but it wasn't associated with a cyclone or tropical low, which *does* make it somewhat extraordinary.

    @Agnostic: IMHO, the one step that will *really* make a difference to Australia's emissions is to announce that no more coal-fired power stations will be permitted to be built. That will get the power companies thinking seriously about alternatives to replace the plants that are approaching retirement. Maybe just start with a ban on brown-coal, with a phase-out of black coal power.
    Now, its possible that the only practical option to replace that much generation in the next 10-20 years is nuclear, but with enough incentive, I'm sure we'd see enormous effort put into developing alternatives (like solar thermal or geothermal).
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  18. JohnD @16,

    So you are suggesting that they are cherry picking? Do you realise that means that you are essentially accusing them of scientific misconduct? I though the house rules did not permit that.

    I understand the findings are inconvenient and troublesome for you, but you trying to hand wave away a paper published in a leading climate journal is pretty ridiculous. Do your own analysis, and demonstrate that shifting the start date renders the trends statistically insignificant. You would also have to argue why you selected your particular start date. you can conclude nothing, because all you have done here is present some musings, some hypotheticals, no data analysis.

    Had you made the effort to read the paper, you would have found the reasons for them selecting the 1911 and 1957 start dates. Why am I do all the work, you are the one making accusations of nefarious goings...read their sections 3 and 4 which describe the data and methods they used, respectively. In fact, please read the entire paper.

    Also note that this paper does not stand on its own, it forms part of a coherent and much larger body of evidence. From their introduction:

    "Changes in the frequency and severity of some extreme events during the twentieth and early twenty-first cen- tury have been recorded globally (Frich et al. 2002; Alexander et al. 2006) and throughout Europe (Klein Tank and Ko ̈ nnen 2003), North America (Karl et al. 1996; Vincent and Mekis 2006), South America (Vincent et al. 2005; Haylock et al. 2006), Asia (Manton et al. 2001; Zhai et al. 2005; You et al. 2008), and Oceania (Plummer et al. 1999; Alexander et al. 2007). These changes have in- cluded increases in the occurrence of hot extremes and decreases in the occurrence of cold extremes of mini- mum and maximum temperature during the second-half of the twentieth century for the majority of global land area (Frich et al. 2002; Alexander et al. 2006). Reported
    changes in extreme precipitation are regionally depen- dent. However, there has been a global trend toward increases in extreme daily precipitation during the second-half of the twentieth century and into the twenty- first century (Alexander et al. 2006)."


    Yes, La Nina's are typically associated with heavier rainfall events over Queensland and NSW, nothing new there. ENSO is, as the name suggests, an oscillation-- it cannot cause a trend unless there is a systematic increase in the intensity and/or frequency. Also, the BOM has also said that the record high ssts around Australia probably played a role. and Trenberth (and others) has shown that the precipitable water vapour content has risen by about 5% since the 70s over the global oceans-- providing more latent energy for storms (and which will also incidentally increase the liquid water content of the convective clouds). there are several papers on that which I can refer you to if you like.

    You are entitled to your own opinions johnd, but not your own facts. Feel free to deceive yourself, but ignoring the huge and overwhelming body of evidence won't make the reality go away.
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  19. It certainly is a remarkable year or so in Australia and globally, I tend to think too many events to dismiss as purely natural variability.

    Scientific scepticism in every area of science seems to go thru several phases:

    Robust and often compelling.
    Necessarry but difficult to quite maintain
    Missleading, tedious, whining, and desperate
    Stupid and despicable.

    What stage are we at with cimate change I wonder?
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  20. In addition to the extreme weather on the Eastern seaboard, this graph of stream flows in the west is worth a look.
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  21. @ farrowed. Wow, that's *really* scary. Given WA has also seen a significant drop in their aquifers as well, it makes you wonder how much longer WA will be able to sustain its current population-let alone expand. South Australia is eventually going to run into problems too-though maybe later than Western Australia. Though we definitely got some excellent rain in late 2010, it doesn't really compensate for the more than 30% decline in Autumn rainfall that we've seen since the 1970's.
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  22. The failure to deal with climate change is THE massive failure of democracy. Why? Because though China is denying it too, it is the 'democratic' nations of the world, the US, UK and others, who are leading the charge into denialism, and giving free reign to denialists under the -cover- of "freedom of speech" and "freedom of commerce" -- even though this is destroying those freedoms along with more basic freedoms for all those who have to grow up in that ruined world full of war, famine and pestilence.
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  23. Bern #17

    Brisbane 2011 surely was a major event - the question is whether it has happened before and with what frequency.

    I would have thought 100-200 years is too short a period to define the range of flood events - and if no-one is prepared to discount the report of John Oxley's 12m as unreliable Aboriginal folklore - then 12m in the last 200 years is the best estimate of the range of natural flood height in the Brisbane river.

    Wivenhoe and Somerset dams were not around in 1893 - so this remains the worst measured 'natural' flood height at about 8.2m - although the overall 1893 rainfall event might have been smaller than 2011.

    1974 had different aspects - there being much higher creek flows in greater Brisbane itself, and less from upstream.

    The point remains that all these events are unique, chaotic and periodic manifestations of the climate system (particularly La Nina) and very difficult to prove are driven outside the range of natural variation by GW or AGW.
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  24. Johnd #16 and albatros#18

    Good points Johnd. Albatros has gone right over the top in his piece at #18.

    I have read a fair bit of Karoly's stuff over the last 18 months and would put it in the 'advocacy science' part of the library catalogue.

    Back to 1911 is too short a period to establish any robust background noise level for climate variation, I would humbly suggest.
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  25. kl Did anyone check whether the indigenous reports of flood high levels were associated with cyclones? afaik, none of the highest water events recorded before 2011 occurred in the absence of a cyclone.
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  26. #25: "the indigenous reports of flood high levels"

    Something suggests to me that if those indigenous reports were to the effect of "It never used to flood here," KL would be discounting them entirely.
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  27. KL @ 24 wants to have his cake and eat it too.

    The established length of time series for climate significance is typically 30 years or more. With a robust enough dataset, shorter periods may also be significant. Numerous times on various threads here at SkS he has proclaimed about the lack of oceanic warming since 2003, but never has that trend risen to the level of statistical significance.

    Now he would have us ignore the results of a dataset going back 100 years for...why, again?

    I would humbly suggest, Ken, that you refrain from characterizations of other people's comments as you have just done with that of Albatross (note the 2nd "s"). That tends to get you in trouble here, as you well know.

    The Yooper
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  28. Albatross at 15:39 PM on 12 February, 2011,
    perhaps you need to go back and carefully read my post that you were replying to, in particular the second last paragraph, and you will see that my post was in fact a response to your comment "Yes, something very different is going on alright."
    As I indicated, I find it prudent when considering any such analysis that compares trends over specified time frames, especially very short time spans such as the one in question, to consider the prevailing conditions at both ends of the surveyed period, and if those conditions were in a state of oscillation, give careful consideration as to whether similar outcomes would be achieved by adjusting the survey period forward or back to a point where the oscillating conditions had changed.
    Rather than passing judgment on the paper itself, I instead indicated the state of the IPO and ENSO cycles at the relevant points, and that doing a due diligence rather than blindly accepting the results, you, or anyone, would be better able to evaluate the value of any conclusions reached.

    If you want to discuss aspects of the paper referred to by you then perhaps one of those aspects that I am giving some thought to is the use of percentiles in determining extreme events.
    In itself it would normally be acceptable, however in the case of precipitation, and specifically precipitation over Australia, as you may or may not be aware, there are large areas with minimal rainfalls as well as areas with tropical rainfalls, and as is well documented, whilst the higher rainfall areas are generally subject to a reasonably regular pattern, in the marginal areas rainfall is both sparse and irregular with long completely dry cycles.
    Whilst it is often made as a joke that there have been kids 10 years old that had never seen rain, it needs to be considered that it is based on fact.

    Getting back to precipitation percentiles, does identifying the extremes from large areas with say a historically irregular 5" rainfall with those from a regular 40" rainfall allow a valid analysis to be made regarding extreme events, and even it was acceptable for the purpose of the analysis, could any worthwhile conclusions be drawn as to what is actually occurring over such a large and diverse land mass?
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  29. Ken Lambert at 23:36 PM on 12 February, 2011, I agree, one of the problems with climate analysis is the reliance on a relatively short data set, and a notion that it all can be analysed through a number of formulas or graphs.
    In Australia there exists a much larger "data base", that being the unofficial information that has been accumulated by both anecdotal evidence and personal records, especially in the agricultural sector. This information is relevant and should be accurate as it documents how the weather and climate manifested itself where it really matters, in the production of food. Historic crop production records are very good proxies that covers broad areas, but more importantly are indicators of whether we are capable of adjusting to any changes the climate has visited upon us now or in the past.

    With regards to the Brisbane floods, whilst there seems to be discussion about the effects of cyclones or otherwise, the bottom line is that it is the terrain that is the ultimate determining factor, and it is irrelevant whether the next flood will be cyclone induced or otherwise.

    Interestingly, the first "extreme" weather event apparently occurred when the first fleet arrived at Botany Bay. Whilst still on board the vessels, the arrivals were subjected to a week of 100 degree temperatures.
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  30. Daniel Bailey at 02:08 AM on 13 February, 2011, it often amuses me how the 30 year period is used by some to make a point about climate trends.

    A few years ago when Australia was in the midst of a drought, time and time again alarmists would trot out a graph showing the decline in rainfall over the preceding 30 years. As I argued back ad-infinitum, the beginning period, the mid 1970's, was likely the wettest period Australia wide since first settlement.
    I constantly had to point out that Australia in fact, was not getting drier, but instead getting wetter as indicated by comparing the second half of the 1900's to the first half, and that in turn to the entire 1800's.

    Now I expect the see the 30 year period being trotted out again, probably by the same people, to support arguments that Australia is now getting wetter given both the current conditions and the fact that 1982 was a bad drought year. :-(
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  31. Here's a 2003 paper that supports a broad perspective on Australian climate change impacts: http://www.edo.org.au/edonsw/site/pdf/subs/climate%20change%20review.pdf A 2000 paper shows that a simple index like "total rainfall" may not be as illuminating as indexes that show rainfall events decreasing while the intensity of the events increases: http://www.vsamp.com/vsamp/resume/publications/Haylock_Nicholls.pdf

    My inclination is to cherry pick some advice from the first paper to emphasize impact mitigation (instead of emission mitigation).
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  32. Johnd @ 30 - and a notion that it all can be analysed through a number of formulas or graphs

    What do you have in mind to replace it?, chicken bones and tea leafs?. Actual analysis shows extreme events are increasing in Australia. It would be nice to have information further back in time, however until someone invents a time machine, we have to use what is available.

    I constantly had to point out that Australia in fact, was not getting drier, but instead getting wetter

    And of course you were constantly wrong. Northern Australia is indeed getting wetter: Weather Extremes Are Growing Trend in Northern Australia, Corals Show and A Combined Climate Extremes Index for the Australian Region - Gallant & Karoly 2010 but that isn't the case for other regions of Australia, as the last decade of drought should have made obvious.

    And when this La Nina is over?. Back to drought again for many regions.
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  33. If this six weeks of extreme weather events in 2011 is an indicator of AGW, then could we assume that six weeks or more of relative inactivity indicates the opposite?

    It's a fair question.
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  34. Marvin @ 34 - If this six weeks of extreme weather events in 2011 is an indicator of AGW, then could we assume that six weeks or more of relative inactivity indicates the opposite?

    If you ignore the preceding 3 centuries of increasingly more extreme weather in Australia, and focus only on the last 6 weeks, then maybe. Sounds a tad unscientific though.
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  35. Rob Painting at 07:18 AM on 13 February, 2011, the conclusions of the Gallant & Karoly 2010 paper were
    "Around the mid-late 1970s, the broad-scale Australian environment changed from a period where colder and drier extremes dominated to one where hotter and wetter extremes were more prevalent. Such changes manifested in annual, seasonal, and daily extremes."
    How does this relate to your own assertions?

    Whilst they noted regional differences, the conclusions were defined as referring to "the broad-scale Australian environment".

    Your comment about the relevance of the most recent drought indicates that perhaps you are more influenced by such short term aberrations rather than the bigger "broad-scale" longer term picture.
    It is only when the status-quo has been re-established after a drought and the ground water reservoirs have been replenished that any indications will become obvious.

    Indeed even in the paper it was the only the focusing on very short time scales, 5 years and less that allowed their conclusions to be reached, and that leads me to wonder what is the relevance of it all as I feel measuring anything less than the time frames that are found in the various ocean based cycles yields little.

    Just as there are shorter and longer periods of dry weather, so too are there shorter and longer periods of wet weather. The systems that bring rain to one region, generally deprive another region of theirs. In Australia's case that means not just regions within Australia, but includes Indonesia, India and Africa all being within the Indian Ocean region.

    One other aspect that I am not sure of in such studies that are analysing extremes is whether or not double counting or worse occurs or not.
    Generally if the systems are such that it brings above average rainfall to one region, another region is deprived of theirs. This should not be counted as two extreme events, but given how it was indicated in the paper that contrasting extreme events were evident in some regions, then I suspect they were accommodated as two separate pieces of data.
    How do you think they have been accommodated, or should be accommodated?

    Recent events worldwide also indicate that perhaps the same may apply to heat, if the various systems coincide in such a way that the heat carried by them is directed into a single region, then it will be at the expense of other regions.
    Any thoughts on that?
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  36. John D - "Your comment about the relevance of the most recent drought indicates that perhaps you are more influenced by such short term aberrations rather than the bigger "broad-scale" longer term picture."

    Define what you mean about aberration. We have over 40 years of a general drying trend in Australia:



    When does your aberration end and non-aberration start?.

    How does this relate to your own assertions?

    From Gallant & Karoly 2010

    John D -"These trends mostly stem from changes in tropical regions during summer and spring."

    I do hope you understand that rainfall totals can fall in a region yet extreme rainfall events can increase. You get that right?. The long term drying trend is what causes drought.
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  37. johnd, instead of seeing Australia as one entity that can only get wetter, drier (whatever it is that you want to argue against), why not have a look at a trend map where you will see that the majority of the country seems to be trending wetter, while a significant minority seems to be trending drier. You see, the two states can exist at the same time in different parts of the country, because Climate is complicated. That is why people easily get confused when they expect Global Warming to mean that warming will occur linearly everywhere, year by year. It's a shame that it needs to be constantly re-iterated.

    As for 30-year trends, laugh at this :

    The World Meteorological Organization (WMO) requires the calculation of averages for consecutive periods of 30 years, with the latest covering the 1961–1990 period. However, many WMO members, including the UK, update their averages at the completion of each decade. Thirty years was chosen as a period long enough to eliminate year-to-year variations.
    MET OFFICE

    I believe you will find that they decided that before Al Gore and all his alarmists thought it would be a good idea to use 30 years, to be mean to all the so-called skeptics...well, according to the so-called skeptics, anyway.
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  38. I thought I would add the actual image from the first link I gave previously, just in case :

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  39. johnd @28,

    "perhaps you need to go back and carefully read my post that you were replying to, in particular the second last paragraph, and you will see that my post was in fact a response to your comment "Yes, something very different is going on alright." "

    First, if you are going to speak to a particular point/sentence, please quote it in your reply at the beginning as I have done here. Second, what you claim in the quote above is not strictly true. You took spent a long time taking issue with the start and end dates and made insinuations of scientific malpractice against the authors.

    You do later say this:

    "Therefore before one can conclude that something very different is going on, other than some short term aberrations, one needs to consider if the beginning and ending points of the study were firstly moved back, say a nominal one decade, and then secondly moved forward one decade, would the same conclusions be reached. "

    The trends are statistically significant, which means that there is enough data to extract a statistically robust/significant signal. I again challenge you to demonstrate that moving the start and/or end dates refutes their conclusions-- anything else on your part is hand waving, speculation and void of science. and again I remind you that this work does not stand alone, but forms part of a much larger coherent body of evidence which shows that rainfall extremes around the globe (including Oz) are increasing.

    And Rob painting @36 makes an excellent point when he says (well when the research has demonstrated):

    "I do hope you understand that rainfall totals can fall in a region yet extreme rainfall events can increase."

    And it still appears to me that you are criticizing a paper which you have not even bothered reading (in full). Have you read the paper johnd?
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  40. Daniel Bailey #27

    Deleting my posts won't change the facts Daniel..

    Johnd and I have made some simple logical points about the range of extreme events in Australia. To suggest that 30 years is a significant period to judge changes in flood/drought events is preposterous.

    Not even 100 years is a significant period when we have seen only one such other drought event (the Federation drought) and one other such flood event in Brisbane (the twin floods of 1893) of similar severity.

    Adelady - as Harry Butler famously said; "The Aboriginals were great naturalists but not great conservationists". They were not crash hot on science either - certainly not up for sailing 12000 miles around the world to observe the transit of Venus or inventing Harrisons clock to measure longitude.

    I have not read his 1824 log for some time but I seem to recall that John Oxley had observed debris high in the trees along the Brisbane river and the local Aborigines were quite agitated about floods - indicating that the 12m flood had been fairly recent in 1824.

    Our cruel and exploitative British ancestors were actually rather good at recording things and navigating their way around - if not too hot at bush survival. I would expect that the 12m height of the debris was a fairly accurate estimate if not actually measured.
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    Moderator Response: [Daniel Bailey] You erroneously assume I deleted your post, which I did not do. My comment was for others to read on the dichotomy of your inconsistent position WRT time series and statistical significance. As to the content of your comments, as long as it complies with the Comment Policy, I leave them alone.
  41. Ken Lambert: Although I am an English teacher and American literature professor by training, I will comment on the "12m" flood datum. You write:

    "In the Brisbane flood 2011, the hydrologist who oversaw the planning of Wivenhoe dam was quoted in the 'Australian' thus:

    'When John Oxley discovered Brisbane 180 years ago, the local Aboriginal people were very agitated about flooding and they showed him high water marks that would have been 12m'."

    To begin with, your dates are very unclear, and the claim put forward about Oxley's "discovery" of Brisbane is a sloppy misuse of the English language.

    My first factual correction: 2011 less 180 yields 1831, a date that is too late for the establishment of the English settlement at North Quay, which took place in 1825 after the penal colony at Redcliffe, dating to 1824, was abandoned. In other words, I must conclude the unnamed hydrologist you say the _Australian_ was quoting in its story about the 2011 flooding actually made this statement in 2004. You should have made this clear.

    Next I will take on the "would have been 12m" figure itself. To begin with, as you present it, this is a number with a very hazy provenance, and hardly one I would bruit about in a triumphalist fashion. Note that the unnamed hydrologist uses the words "would have been" to introduce the number, a verbal hedge that suggests the possibility that either Oxley or the hydrologist was skeptical of the claim. With that in mind, before anyone can comment on the validity of the claim, the very first thing that would need to be done is to look into Oxley's writings,extract the relevant data, and evaluate it for its actual value.

    Thus, your apparent belief that you have scored a great point by citing this putative record of a 12 meter flood is not exactly founded on sound scientific methodology.
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  42. Ken Lambert @40 - To suggest that 30 years is a significant period to judge changes in flood/drought events is preposterous........Not even 100 years is a significant period .

    And yet you drone on and on and on......... about ocean heat content over a 5 year period, when the ARGO & XBTproblems have yet to be sorted. Do you see your lack of internal consistency?.
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  43. Don9000 #41

    The piece was from the Weekend Australian Jan22-23 pp10 reported by Tony Koch. The hydrologist quoted was Neal Ashkanasy. The 180 years was no doubt a cursory expression -a pedant would have said '187 years ago'.

    So no Don9000 - the hydrologist did not say this in 2004 - he said it in response to the 2011 flood.

    When I get time I will look up the exact reference in the John Oxley library in Brisbane. An old school book on my shelf records that Oxley 'discovered' the site for Brisbane city on 20th September 1824. Is that date close enough??
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  44. Rob Painting #42

    "Do you see your lack of internal consistency?." Err No!!

    The OHC 5 year period is in reference to an OHC graph touted on this website which covers the period 1993-2010 - a 17 year period. Is not 5 years a significant part of a 17 year period?; Especially when that period has seen the full deployment of Argo which (by the sheer number of measurements from 3000+ buoys) should bring much greater accuracy to same.
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