This will cause:
"increases in droughts, floods, fire, tropical cyclones and hail"
"large areas of mainland Australia are likely to have less soil moisture"
Expect heavier rainfall events, and the number people who will die every year over the age of 65 from heat waves will increase from 1000 (current) to 2300 to 2500 in 2030 to 4300-6300 in 2050. (or they could just buy air conditioners).
The murray darling basin had the driest September on record and they forecast rainfall in Australia to decline by at least 10%, especially in winter and spring.
And as their website says:
Since 1950, most of eastern and south-western Australia has experienced substantial rainfall declines. Across New South Wales and Queensland these rainfall trends partly reflect a very wet period around the 1950s, though recent years have been unusually dry. In contrast, north-west Australia has become wetter over this period, mostly during summer.
From 1950 to 2005, extreme daily rainfall intensity and frequency has increased in north-western and central Australia and over the western tablelands of New South Wales, but decreased in the south-east and south-west and along the central east coast.
Where to start! I have noted before that there is no evidence of increased drought, and there is no evidence of increased hail or very wet weather scenarios.
And increased cyclones? Nope, no evidence of that. If anything, cyclones are decreasing in Australia.
The Murray darling basin did have the driest September on record, but there is no evidence that we have a decreasing trend there. Long term trends suggest no evidence of decreasing rainfall.
I questioned Dr. Scott Power as to why the north west Australia has cooled down. He replied that it is due to increased cloud cover in that area, hence why it has seen more rain. Of course the reason south east Australia has warmed up is not due to less cloud cover (and less rain) but due to global warming.
I also asked him if under the theory of global warming, do we see temperatures constantly increasing throughout the day, in other words, are night time temperatures increasing at a similar rate to day time temperatures.
I expected an answer of yes, but he "correctly" pointed out that that night time temperatures are increasing at a greater rate (this mind you is due to analysis of the minimum temperatures which as we all know doesn't even occur a night). On questioning why this is, he said he didn't know, despite the fact he did a paper on it. He thinks it might have something to do with increased cloud cover, but he's not sure. Ahh, cloud cover!
But what Dr. Scott Power did mention on many times is the decreasing trend of rainfall since 1950, and because of this the expected continued decrease due to global warming.
I questioned this, and commented that rainfall was actually higher in the last 65 yeas than in the 50 before that. He agreed with me saying that they were very constant back then. A lot more variability now, but continued to say that we are seeing a decreasing trend since 1950.
So are we seeing a decreasing trend in rainfall in the last 50 years. Lets look at the stats:
My regression tells me in fact the complete opposite. Since 1950 Australia has seen an increase in rainfall at a rate of 0.79mm extra per year. Hence in 1950 we averaged around 456mm and then now averaging around 500mm, a 44mm increase since 1950.
So where is this decrease? Note the above is however not statistically significant (p = 0.3).
But is this Australia wide? Victoria is the only state to record a significant decrease in rainfall since 1950 (p=0.03), whilst South Australia, Western Australia and the Northern Territory all record significant increases in rainfall. Queensland, New South Wales and Tasmania all record decreases in rainfall, but it is not significant.
Keeping mind however, that all states, every single one has had on average 10% more rainfall from 1950 to 2006 than from 1900 to 1950.
So where are the decreases in rainfall? Seriously, where are they? And how on earth can one continue to predict decreasing rainfall, when Australia has had nothing but the opposite.
I do hope that someone answers my 3 questions to the CSIRO, which will be posted in the next post
39 comments:
The doomsdays concentrate on all the negatives. For instance, global warming will decrease the number of deaths in UK and Europe. The doomsdayers only talk about the extra deaths from the increased temps. many more people die worldwide from cold than heat.
hey Jonathan
Keep up the good work
As someone who was around at the time I remember floods in the mid 50's - sandbags along the Murray etc. If it had stayed that wet we would be building Arks.
Are you for real?
No wonder CSIRO haven't responded. Does rain fall evenly across the nation. Are droughts always uniform across Australia. Is our agriculture evnly distributed. Ever considered the average of a high and low might be not representative of anything useful at all. You're the one doing stats.
There are major spatial trends. A percentile analysis will show you headwaters of the MDB worst on record on a multi-year percentile. If you get a bit sophistamuckated you will see that simulated inflows are far worse in SE QLd and the MDB than the Federation drought.
SW WA and eastern Australia have major rainfall trends.
Then you might bother to see if any climatalogical changes might be occurring with say El Nino, Southern Annular Mode, Tasman Sea and Indian Ocean temperatures.
Of course it's easy to get trends off the wet 1950s which is why you need some sophistication in your thinking.
And you also have to think what might be natural and what might be AGW related. Nobody said you can't have both.
Looking a Australia wide area averages when there are marked regional patterns is USELESS !!
Hi Luke,
I agree that "the average of a high and low might be not representative of anything useful at all", but that is wrongfully how the trends in temperature is calculated at present.
I agree that inflows are less, this is what happens when you have a few years in a row of decreased rainfall. But this is not just a thing of the recent.
If you had bothered to read my post or the blog, you would realise that a lot of what I do looks at individual stations and areas. The post said that every state has increased rainfall in the second half of the 20th century than the first, ranging from a 6% increase in TAS to a 16% increase in NSW
SW WA (a climate changers pet) has a long record of significant decreases in rainfall, this is for sure, however whilst a few recent years have been down, there has been no significant decrease in rainfall for eastern Australia (which is against what you say). Check the stats! So too south eastern AU
as noted above:
"Victoria is the only state to record a significant decrease in rainfall since 1950 (p=0.03), whilst South Australia, Western Australia, Tasmania and the Northern Territory all record significant increases in rainfall. Queensland and New South Wales all record decreases in rainfall, but it is not significant."
Perhaps you would like to answer my 3 questions to the CSIRO?
Have been cynically discussing at denialist central - aka
http://www.jennifermarohasy.com/blog/archives/002452.html#comments
Minimum temp after dawn - well yep sometimes. But really a trivial point - do you think the minimum might be a general (not perfect) proxy for what happened during the night or does temperature suddenly crash 3 mins after dawn. Nit pick issue IMO.
Rainfall predictions - too early to tell as it's a "prediction".
You quote eastern Australia.
But again eastern Australia is a very big place – Cape York to the Prom. Tassie even. You might even argue do you trust their areal averaging in places like central and NW Australia and Cape York with sparse networks - big biases. So you're doing the most bluntest of analyses.
Look at the spatial maps at http://www.bom.gov.au/cgi-bin/silo/reg/cli_chg/trendmaps.cgi - you have massive spatial changes and farmers and water managers too well know.
You also have to think when the greenhouse forcing would have become significant. 1900? 1950? 1970? 1980? now? not yet? So why regress from 1900?
Major theory for NW WA becoming wetter is changes in monsoons from indirect effect of circulation changes due to Asian aerosols.
http://www.csiro.au/news/ps2l5.html
Maybe?
Scale of analysis is very important - central Qld is drying out. Brisbane City rainfall might be OK but go 50km inland to the Wivenhoe Dam catchment. Different story. Spatial scale and location are massively important.
Also rainfall is terribly blunt - it's pattern of rainfall, distribution, antecedent conditions. Humidity effects. So you really need to go to a wheat or pasture model with full evapotranspiration to be effective. And the hydrologists go to simulated runoff. Otherwise you really don't know. All these things tend to amplify impacts (usually).
You also have to see if you can mechanistically pull things apart with GCMs - e.g. someone right on this is Wenju Cai http://www.greenhouse2007.com/downloads/keynotes/071004_Cai.pdf
http://www.csiro.au/news/AustralianRainfallFuture.html
Of course some of this is natural. But some is very likely greenhouse, but not normal greenhouse perhaps. e.g. SAM - why have non – El Nino years (so-called SOI neutral years) also not delivered. http://www.sciencemag.org/cgi/content/abstract/296/5569/895
Also less El Ninos since 1976, La Ninas that don't fire, few coast crossing tropical cyclones in Queensland.
Worst on record drought for runoff on Murray and SE Qld catchments. Ongoing drought since early 1990s in much of Qld & NSW.
SW WA is a mix of both natural & greenhouse IMO - why does it have to be "exclusive". Why would it be even??
So simply doing national or eastern Australian annual analyses is not worth zip - will only get wry smiles from CSIRO.
What farmers want to know is trends in drought and production from rainfall - not simplistic unrevealing wide spatial averages. Tell a Murray Valley orchardist nothing is going on !!
You should get yourself along to the annual CSIRO open climate reviews (May I think) - you may find it educational and less uniform in view than you might suppose. You can take potshots and fancy yourself as Galileo or engage.
Oh yea 17 models - see Marohasy site
P.S. Other interesting sideline is having a look at frost Stone, R., Nicholls, N., and Hammer, G. (1996). Frost in
northeast Australia: trends and influences of phases of the
southern oscillation. Journal of Climate 9, 1896-909.
"Minimum temp after dawn - well yep sometimes. But really a trivial point - do you think the minimum might be a general (not perfect) proxy for what happened during the night or does temperature suddenly crash 3 mins after dawn. Nit pick issue IMO."
Not at all. As shown here, temperatures in Australia are not increasing over night, despite increases in minimum temperature.
Jonathon - sigh you've done it again haven't you. Spatially averaging of hot and cold. (1) statisticians often see but don't understand (2) you're brave boy slagging off BoM's statistical ability without any engagement from them - many have some a cropper.
You've calculated national average anomalies over spatially variable data with no areal weighting and with stations of unknown quality. And who do you think was up in the wee hours measuring temperature all around Australia. Quality of stations?? Automatic stations have not been there for long. Are the data daylight saving adjusted?
Analysis not worth a zac without some understanding of the data you are analysing! Do you really think BoM are that stupid?
Do you think trends in frost might tell us something?
Luke said You also have to think when the greenhouse forcing would have become significant. 1900? 1950? 1970? 1980? now? not yet? So why regress from 1900??
Ummm because thats when records start ie. the biggest sample to look at. Also would include more natural variation which you should include when looking for trends. You said yourself it's easy to get trends off the wet 1950s. Isn't this exactly what the BOM/CSIRO are doing?
sorry Luke, my analysis is also conducted at individual station level. And as far as trends in frost goes, I presume you don't know that trends in frost is calculated as number of times the minimum temperature is less than 0 degrees. Once again, dependent on a variable that occurs during sunlight.
Dave = yep and the 70s were wet too - it's a difficult problem and yoy can only keep doing smaller analyses with attendant problems of significance and as well as looking at other phenomena. Like the 1950s, the 1970s were also wet. La Nina, IPO and all that. A gun statistician like young Jonathon here should be whipping out a power spectrum or something sophistamuckated -surely looking at time series when we have decadal phenomena is pretty dodgy. You could try to remove an IPO decadal effect and an SOI El Nino/La Nina effect I guess.
Jonathon - you may have conducted temp analyses at individual stations - but where spatially - did you weight for area? e.g. SW WA rainfall is declining so why would you average with the Kimberley - similar things can happen with temperature due to regime shifts. Have a look at BoM's spatial temperature maps.
If you get a couple of really good stations with some hourly measurments and adjusted for daylight saving etc etc I'd be very impressed if over a long period that the early hours of the morning were not correlated with the daily miniumum.
Have a look at your own anomaly plots - certain years are not aligning with other years - some midnights do not correlate with 3am and 6am in quite a few years. Seems all very strange and so I have to be very suspicious of the data sets.
Which is why you should visit with Blair Trewin or David Jones in BoM and get some opinions instead of bolshing with the bravado !
Again - total rainfall is very blunt - simulated wheat yield, pasture growth or dam storage inflows would be much more interesting as variables as that what affects us all.
When I look at Cai's powerpoint here http://www.greenhouse2007.com/downloads/keynotes/071004_Cai.pdf I see an Australia with some very big trends spatially (Slide 3) and a Murray River system with a drought off the scale and ongoing. Look at storage levels. (Slide 4)
Maybe the bitch of a La Nina that refuses to deliver might bring some rain soon.
You see guys farmers, bankers, water managers and policy officers need to know whether the next 120 years will be a sample of the last 120 years. Should they defend, invest, retract, retreat or leave for elsewhere (like the Kimberley) ?? Do we build dams that may not fill?
These are the BIG individual, corporate, social and policy questions.
No I don't work for BoM or CSIRO. So no advert !
P.S. Can't help but notice God's humour in Cai's slide 14.
When I look at Cai's powerpoint here http://www.greenhouse2007.com/downloads/keynotes/071004_Cai.pdf I see an Australia with some very big trends spatially (Slide 3)
I see some cherry picked starting point to make the trends look larger than they actually are.
You see guys farmers, bankers, water managers and policy officers need to know whether the next 120 years will be a sample of the last 120 years.
Good luck with that the BOM can't even manage a reliable 3 month rainfall projection.
also Midnight temp anomalies and 3am temp anomalies correlate at r2=69%
Jonathon - it behoves you to show your analysis to the National Climate Centre - I encourage you to not be an isolationist. You'll get even further with some engagement (even if it hurts initially). Plus adds to your credibility.
Dave - yes you can argue a cherry pick but anywhere you start after 1976 you're going to see dry dry and more dry. So instead of being dismissive check it out !
Frankly I don't think it changes the story that much.
What farmers, bankers, corporates and policy makers are worried about is slide 5 here. Map of Aussie & dams slide in http://www.greenhouse2007.com/downloads/keynotes/071002_Mummery.pdf
Sums up the angst - note the percentile runs 2002-2006 - record bad run
Also check the temperature anomlies - way up over southern Australia adding to increased evaporative flux - makes it worse.
And see the Murray inflows here http://www.mdbc.gov.au/__data/page/1366/RMSystem_Drought_Update10_October07.pdf
Frankly I would be surprised given these results, chnages in El Nino behaviour, Souther Annular Mode, Indian Ocean Dipole and a warming Tasman that you guys wouldn't be a tad curious at least.
Be sceptical - don't los eyour curiousity.
And yes Dave you can slag off BoM's forecasts but that's not the point - what's your advice to a farmer who asks whether this is exceptional, is there any mechanistic evidence of some AGW involvement, and whether teh future will simply be a sub-set of the past.
Don't know is NOT helpful.
And a cock-sure - no way AGW is too cock-sure.
Curious?
Some people are living it.
And the real issue - if it rains tomorrow - 10 years to recover economically and how long till the next drought. You see it will rain again but thinking "it's back to normal" after the enxt decent rain is the classic "hydro-illogical cycle" trap.
So what's correlation with 6am.
and the minima
Tell us about your data points, selection and any area averaging?
Don't leave me gussing.
I m in th eprocess of negotiatin a Phd and publishing this research. Here is a brief outline of the data:
link try again
and time temperature anomaly correlations.
Midnight to 3am: 0.823
3am to 6am: 0.951
Midnight to 3am: 0.775
all obviously statistically significant (p<0.001)
I need to knock on of Luke's myths on the head. Rainfall in the SW of WA did indeed decline around 1970. Although this was really just a return to the pre 1950 rainfall norm. Since then rainfall has been remarkably consistent - much more consistent than earlier years. We did have a couple of relatively dry years around 2000 (nothing compared to the dry years earlier in the century), but this year has been the wettest in a decade.
The problem is inflows into dams have declined very substantially (although not this year). This is due to elimination of brush cutting in the catchment areas and has very little to do with rainfall. Trees use a lot of water. More trees means less water in dams. Its that simple.
I can't speak about the Murray-Darling but you seem to confuse rainfall and stream inflows.
Phillip - record low rainfall in Murray headwaters and record low inflows into the system.
Do you have a reference or study on vegetation thickening in Perth catchments?
Jonathon - and correlation with minima is?
That's a remarkably small sample size for a climate network. Misses many of the intersting regional patterns.
And lastly if you look at Fig 6 here on page 12 http://www.ioci.org.au/publications/pdf/IOCI_TechnicalReport02.pdf
Looks to that the region has undergone a step change relative to the majority of the 20th century
Midnight to min: 0.695
3am to min 0.854
6am to min 0.895
as one would expect. All significant, and stronger correlation as you get closer to min time.
Below is a link to an article on the subject. Note the large reduction in rainfall variability since 1970.
http://www.warwickhughes.com/water/thinning.html
Warwick Hughe's site has several articles on Perth rainfall and water inflows.
D@@@ Blogger crap. The link needs a /thinning at the end.
yep make sure you put in the html format for posting links. eg:
[a href="http://www.crap.com]crap webpage[/a]
but replace the [ and ] with < and >
So we have really good correlations of 3am and 6am with the min as we'd expect. And so all those articles I've seen with increasing minima are "wrong". I have to say I'm astounded. Pick one - try Gayndah !
On Warwick Hughes - funnily enough I figured you would say that. Have to say I find Warwick very hard to believe on many issues. His site was down and I could not check the Perth water article which I has previously skimmed.
Luke I never said that minima was not increasing. Please do not attempt to misquote me.
So the minima are increasing and you have good correlations 3am and they are not increasing too ???? WOW !
Luke I knew you were going to come to such illogical conclusions. You suggest that:
"minimums are increasing, minimums are correlated with 3am and 6am temps, so 3am and 6am temps are increasing too"
Unfort. for you, this is incorrect logic.
Jonathon - as you have said - don't put words into my mouth - you're making the running here. Pulling a discourse out of you is tedious. You could easily put all this to bed and stop being evasive. Your whole thesis goes against stacks of previous work.
One datum point in Central Qld too - jeez !! I have seen lots of CQ data sets with minima increasing.
And so given your correlations with 3am etc you would suggest I would see nothing in 3am series?? Bizarre !
And given frost trends which even farmers have noticed of course the winters are getting milder on average. I mean REALLY !!
But you know better so good luck with it.
"Your whole thesis goes against stacks of previous work"
Name one. You can't because no one has analysed temperature differences at strict times. My analysis o minimum and maximum temperatures (which is the only variables that previous research has looked at) is in agreement with previous work.
Once again you assume that because 3am temps are correlated with min temps the same trends should appear. Bad logic I'm afraid.
and frosts? as I said, based on min temp only. Bad analysis. Bad data.
You don't have strict times for a start - daylight saving? Are you sure.
Your sample size is limited and unrepresentative IMO.
And I'm not playing guessing games with 100 incremental posts to work out "guess what's next".
You have the regression stats I don't.
Oh well I suppose I'll have to do an analysis myself.
I wonder if Luke can patiently expain to us proles how his flurry of assertions about "spatial trends" and "regression stats" invalidates Jonathan's refutation of the myth that Australia's current drought is the result of man-made global warming. Yeah, rainfall may have increased since 1950 but that's just taking national averages, man! It doesn't mean a thing because there are regional variations.......gasp!!!!!
Or is Luke just trying to blind us with regression coefficients?
Keyser soze - I'm not sure of your point. I'll do my best with what I think you're saying.
It's not possible to really know whether AGW has caused this drought. It's also silly to assume absolutely not influence either.
I suspect looking at a range of evidence there's a bit of both and some complex interactions.
And suspend your disbelief for a moment - if AGW did exist and was having an influence would natural variability suddenly disappear?? THINK HARD HERE BEFORE CONTINUING.
The argument against - have had bad droughts before such as the Federation drought.
(but a deep analysis will show this is much worse in parts e.g. Murray River inflows).
Coral cores show 20 year droughts (but the Burdekin outflow is not south-east Australia)
Long climate models runs can show multi-year droughts runs. (but you guys don’t believe models so…)
On the other hand:
We have had more El Ninos since 1976 and the Southern Oscillation has changed significantly. We have had very few big wet coast-crossing tropical cyclones in Queensland. Argument against – Pacific Decadal influences and paleo-record
Indian Ocean has warmed. Tasman Sea has really warmed.
Southern Annular Mode around Antarctica has changed significantly. Can be drawn back to greenhouse/stratospheric ozone interaction. http://www.sciencemag.org/cgi/content/abstract/296/5569/895
The evaporative demand in this drought sequence is much worse than the Federation (Nicholls) – temperatures are up.
So the modelling can relate a fair bit of influence back onto this drought sequence.
My opinion – I think there’s an AGW “influence” on balance.
Can it be proved – come back in 30 years.
Does this help – well unlike us real people in the real world need to make BIG decisions. – NOW !! To sell the farm or stay, invest or retreat, to move elsewhere like the Ord River area. Bankers need to decide whether to loan. Federal Treasury are very nervous about billions and billions in drought aid going out the door. Hasn’t stopped since 1991.
http://www.abc.net.au/news/stories/2007/10/26/2071385.htm
So when you spread all the facts, maps, graphs, science papers out on the kitchen table it’s a worrying story. Even if AGW has no influence we need to know how often this sort of sequence can happen. Simply ruinous to the nation potentially.
What would expect to see if AGW was having an influence – warming oceaning, changing circulation patterns. Would you have trouble initially seeing a climate change signal emerging from a background of climate variability. Yep !
As a senior climatologist said to me the other day – you’d think the denialists would at least be a bit more curious and not so simply dismissive. You need to have insight and understand as well as observe. Simply looking at graphs and statistics won’t give you a complete story – you need to look at the meteorology and mechanisms as well. Otherwise you have a totally impoverished science view with no understanding of processes at work.
See slide 5 here http://www.greenhouse2007.com/downloads/keynotes/071002_Mummery.pdf
Then see Cai’s presentation in general (page 14 for the pundits !!)
http://www.greenhouse2007.com/downloads/keynotes/071004_Cai.pdf
And do you feel lucky with these numbers?
http://www.mdbc.gov.au/__data/page/1366/RMSystem_Drought_Update10_October07.pdf
Luke, you say deniers are dismissive but I find it's the other way around. Anyone not following the fashion and declaring global warming is "settled" is dismissed as a crank. I've learnt to be sceptical about doomsaying in general because I've seen a hell of a lot of it and NONE of it has come true. So when I hear that doom is nigh I get a bit stubborn - especially when the doomsayers are trying to take control of large parts of our lives.
You say we don't accept modelling but also say that there's a lot of stuff we don't understand. Well, I'm sorry, but if we don't understand exactly what's going on then computers with models based on positive feedback mechanisms aren't likely to come close to being right. In fact, much of the debate....actually, there's only debate on one side.......much of the schism is simply a matter of whether you opt for negative or positive feedback as the most likely mechanism affecting the weather.
Simply looking at graphs and statistics won’t give you a complete story
Isn't that how they identified global warming to begin with? Now the graphs and statistics aren't agreeing with "the story" anymore we suddenly need to look at the meteorology and mechanisms. Doesn't fill me with confidence as neither are well understood.
And yes Dave you can slag off BoM's forecasts but that's not the point - what's your advice to a farmer who asks whether this is exceptional, is there any mechanistic evidence of some AGW involvement, and whether teh future will simply be a sub-set of the past.
My answer would be "how long is a piece of string"
Don't know is NOT helpful.
So you'd rather make up something that doesn't eventuate?
how do the CSIRO claim that we will get less rainfall when the science suggests that global warming will increase rainfall?
There are a couple of points I wish I could point out.
In Melbourne's catchment areas rainfall has decreased by around 30 percent (almost two standard deviations) since 1997, even during La Nina years. There is already clear evidence that global warming has shifted the jet streams well south of southern Victoria, removing its winter rain. Evidence from crater lakes further west is that this dry spell is completely unprecedented in the Holocene and cannot be part of climate cycles. Yet, Brumby is still calling for more roads when what is needed is a plan to restore pre-industrial carbon dioxide levels via road demolition and investment in rail and bike paths.
In the Eucla and Goldfields of Western Australia, rainfall has increased by forty to fifty percent since 1967. Moreover, models suggest Asian aerosols should not increase rainfall in those regions at all. Ian Smith, for one, is willing to admit the likely culpability of AGW for these changes, showing that increased greenhouse gases have stopped the cooling of inland Australia that allows the southern depressions to advance into the continent and encourages upper-level flows into the Eucla and Goldfields in a way never seen before.
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