An understandable response, Sir Vivor, but the UK Met data was used because it was such a significant change over just two decades. The Australian data sets show much milder changes over a longer period but the same sort of changes take place. Shift the UK data to suit the southern hemisphere and you will have a useful guide to what is taking place here as well.

The other important thing to note is that the "global warming causes extreme bushfires" argument appears to be directly at variance with the majority theory on CO2 feedbacks. If GW is being driven by CO2 emissions etc then it certainly will show up as warmer nights rather than hotter days because the CO2 allows the short wavelength solar heat to pass through during the day but traps the long-wave radiation at night.

If this were the other way round, and GW was in the form of higher daytime temperatures, then that would mean that Global Warming was being caused by an increase in solar radiation, not by greenhouse gas.

So the people who are arguing that global warming is caused by CO2 cannot then turn around and claim that it is exhibiting the attributes of a warming caused by increased solar forcing.

You cannot have it both ways. But clearly, elements of the CO2 Flux Clan don't seem to bother about such fundamental inconsistencies.

Perseus re:
" ... UK Met data was used because it was such a significant change over just two decades. The Australian data sets show much milder changes over a longer period but the same sort of changes take place. Shift the UK data to suit the southern hemisphere and you will have a useful guide to what is taking place here as well.

1. UK Met data was used by you in your argument. My guess is that you are an amateur, like myself. I doubt an expert would so boldly assume that UK data is good for predicting to local Victorian climate trends.

2. "The same sort of changes take place". Do they? I'm skeptical of your evidence and your interpretation. What sort? How much the same? All very vague, but somehow meant to imply certainty?

3. Taz' comments about SST and storm cells are interesting and relevant to the question of whether greenhouse warming will increase the risk of bushfires. Likewise Admiral von Schneider's remarks on ENSO.

There is no clear picture at the present about how ENSO will be affected by CO2 increases - the models give divided results, according to a 2006 study. The wikipedia article,
http://en.wikipedia.org/wiki/El_Nino#ENSO_and_global_warming
which offers an introduction, states:

"ENSO and global warming"
"A few years ago, attribution of recent changes (if any) in ENSO or predictions of future changes were very weak.[10] More recent results[11] tend to suggest that the projected tropical warming may follow a somewhat El Niño-like spatial pattern, without necessarily altering the variability about this pattern, while the ENSO cycle may be minimally shortened[12]."

[12] is at:
http://www.ocgy.ubc.ca/~yzq/books/paper5_IPCC_revised/Merryfield2006.pdf
It is a very dense read - the conclusion is worth the struggle. The Wikipedia article seems to me to be a fair summary. The upshot, IMHO, is that on the average, Australia will get warmer, bush fuel will get dryer, maximum and minimum summer temperatures will increase and bushfire risk will also increase.

Perhaps we can hear from an expert on the subject, or perhaps you have a more pertinent link than your UK climate data?

What a convenient sidestep for you Sir Vivor. Is the current warming being driven by increased solar activity or increased greenhouse gas? If it is from increased CO2 then it will be manifest as higher night time and winter minimums, not higher summer maximums. And if the summer maximums are essentially the same then the GW bushfires "scarenario" goes out the window.

If you accept that global temperatures have increased by only 0.7C over the past century then you must also accept that a change of 0.53C from the 1980's to the 1990's, as in the UK Met data, is very significant. The changes in global mean temperature over the same decade to decade average was only 0.16C, from a mean 14.051C over 1980-1989 to a mean 14.210C over 1990-1999. So to suggest that the 3.3 times more extreme change for the UK cannot inform us as to the nature and extent of local changes is pure sophistry. It beggars belief that a change that is 3.3 times more extreme than the global change would comprise abnormally mild and unrepresentative elements of that change.

Blind Freddy would conclude that a more modest change in temperature, like we have had in Australia, is likely to comprise of even more modest elements of change, not more extreme ones. That is, the rise is even more likely to have come from higher winter and overnight minimums. This is especially the case when the recently revised North American data (NOAA) shows that the recent highs have not exceeded those of the 1930's.

I hesitate to interrupt an intriguing debate between Persues and Sir Vivor but ....
From 1944 to 1982 there were 'cool' burns undertaken by graziers, timber etc interests as well as deliberate burns by what was the Lands Department. One of the Three Commissioners of the old Victorian Forestry Commission was Mr Athol Hodgson who has told me personally that in those days there was an annual total around 350,000 ha of cool burns.
The vast majority of those burns were autumn burns because it was often too wet in winter and spring burning could be very damaging to some flora and fauna. Burning was usually upwards from the riparian zone because lightning always strikes the tops of hills, never the valleys.
In Western Australia they burn in autumn and quite a lot of burning in spring, but they protect sites that could be damaged by any fire. With mosaic burning around sensitive areas they protect those habitats that are essential for some species to survive. This reduces the risk of a hyper or feral fire wiping it out that habitat completely.
IF GLOBAL WARMING is going to dry out our vegetation, isn't it just feasible that we will be able to cool burn in winter?
While your discussion is intriguing and most enlightening (and I really am enjoying it), we are still left with the question of what to do with millions of hectares of public land in Victoria that needs cool burning OR ANY OTHER PRESCRIPTION to reduce fuel levels.
At the rate we are going there will be very little native flora and fauna left to protect.
Are we, I wonder, interested in the fate of the natural flora and fauna or are we just having an educated debate?

The problem with all the would be scientists is the “must wait” for the event to be over before reaching any conclusions.

My problem in minding practical measurements for the math buffs to analyse was how to tell them what situation the peaks and troughs were really leading too. Good engineers need to work to the worst case scenarios ie those times when the road disappears as the bridge collapses or the length of time a gas leak can go undetected before some thing ignites it. An unreported fire a week was about the average in one of our largest petro chem. Complexes. Elsewhere lightening put a lot of sludge pumps out of action at the same nominal frequency. Muggins learned to extract important instruments with a hammer and chisel to speed up recovery with much of it still raining down. Science isn’t particularly good in such circumstances.

The global warming time frame can be quite short given the possibility of positive feedback in the drivers both natural and unnatural. Using our imagination is all that is needed to get a handle on the size of the chaos from just a few minor bumps in the old order of things. By that I mean only those conditions that we would normally expect to weather in a lifetime.

Climate change is measured in many ways. Look around at the ground and see what it grows today compared to what it used too. Count the number of “perfect days,” ie. cloudless skies and no wind! Seasons are early again going by blossom and migrating birds. Inshore fishing will be another tale.

Gaia for what she is worth has her job cut out ramping up negative feedback allover.

Pheonix94: Cool burns up any gulley in my region today, the ACT, the Monaro, the Snowy etc would have to be all out by say 11 AM which was the time the first big gust smashed my old cheval mirror at the markets. All surface moisture after the odd showers over winter was blown away weeks ago.

There is one other way to explain why global warming will have a minimal effect on bushfire intensity, that is raw probability.

The global mean temperature number is made up of a large number of annual means from individual stations all over the world (but with a heavy bias towards settled land based stations) Each of these annual mean temperature numbers is made up of 12 monthly mean daily maxima and 12 monthly mean nightly minima. That is 24 records that make an annual mean.

So in a theoretical scenario where every one of those 24 records exhibits an equal rise in temperature consistent with the global trend, only 3, the summer daytime maximums, are known to exacerbate bushfire intensity. The other 21 inputs to the annual mean (87.5%) do so at times that do not exacerbate bushfire intensity.

In all, 18 of the inputs (75%) take place right outside the bushfire danger periods while another 3 (12.5%), the summer nighttime minimums, merely reduce the normal nightly dampening of daytime intensity.

So even in a theoretical sense, with an evenly weighted input to the annual mean figure, MOST GLOBAL WARMING DOES NOT EXACERBATE BUSHFIRE INTENSITY.

And in the real world we know that these inputs are not evenly weighted. The source of the recorded increases in mean temperature are strongly weighted towards the records that have no relevance to bushfire intensity.

Nightly minimums contribute more to global warming than daily maximums and the contribution of both are heavily weighted towards winter, autumn and spring.

Global warming induced bushfires are such a marginal event that any mention of them can only regarded as a deliberate attempt to obscure the real causes, that is, incompetent forest management and insufficient fuel reduction burning.