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Bushfires and extreme heat in south-east Australia

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Guest commentary by David Karoly, Professor of Meteorology at the University of Melbourne in Australia

On Saturday 7 February 2009, Australia experienced its worst natural disaster in more than 100 years, when catastrophic bushfires killed more than 200 people and destroyed more than 1800 homes in Victoria, Australia. These fires occurred on a day of unprecedented high temperatures in south-east Australia, part of a heat wave that started 10 days earlier, and a record dry spell.

This has been written from Melbourne, Australia, exactly one week after the fires, just enough time to pause and reflect on this tragedy and the extraordinary weather that led to it. First, I want to express my sincere sympathy to all who have lost family members or friends and all who have suffered through this disaster.

There has been very high global media coverage of this natural disaster and, of course, speculation on the possible role of climate change in these fires. So, did climate change cause these fires? The simple answer is “No!” Climate change did not start the fires. Unfortunately, it appears that one or more of the fires may have been lit by arsonists, others may have started by accident and some may have been started by fallen power lines, lightning or other natural causes.

Maybe there is a different way to phrase that question: In what way, if any, is climate change likely to have affected these bush fires?

To answer that question, we need to look at the history of fires and fire weather over the last hundred years or so. Bushfires are a regular occurrence in south-east Australia, with previous disastrous fires on Ash Wednesday, 16 February 1983, and Black Friday, 13 January 1939, both of which led to significant loss of life and property. Fortunately, a recent report “Bushfire Weather in Southeast Australia: Recent Trends and Projected Climate Change Impacts”(ref. 1) in 2007 provides a comprehensive assessment on this topic. In addition, a Special Climate Statement(ref 2) from the Australian Bureau of Meteorology describes the extraordinary heat wave and drought conditions at the time of the fires.

Following the Black Friday fires, the MacArthur Forest Fire Danger Index (FFDI) was developed in the 1960s as an empirical indicator of weather conditions associated with high and extreme fire danger and the difficulty of fire suppression. The FFDI is the product of terms related to exponentials of maximum temperature, relative humidity, wind speed, and dryness of fuel (measured using a drought factor). Each of these terms is related to environmental factors affecting the severity of bushfire conditions. The formula for FFDI is given in the report on Bushfire Weather in Southeast Australia. The FFDI scale is used for the rating of fire danger and the declaration of total fire ban days in Victoria.

Fire Danger Rating           FFDI range
High                          12 to 25
Very High                     25 to 50
Extreme                         >50

The FFDI scale was developed so that the disastrous Black Friday fires in 1939 had an FFDI of 100.

To understand the environmental conditions associated with the catastrophic bushfires on 7 February 2009, we need to consider each of the factors and the possible role of climate change in them.

Maximum temperature: This is the easiest factor to consider. Melbourne and much of Victoria had record high maximum temperatures on 7 February (2). Melbourne set a new record maximum of 46.4°C, 0.8°C hotter than the previous all-time record on Black Friday 1939 and 3°C higher than the previous February record set on 8 February 1983 (the day of a dramatic dust storm in Melbourne), based on more than 100 years of observations. But maybe the urban heat island in Melbourne has influenced these new records. That may be true for Melbourne, but many other stations in Victoria set new all-time record maximum temperatures on 7 February, including the high-quality rural site of Laverton, near Melbourne, with a new record maximum temperature of 47.5°C, 2.5°C higher than its previous record in 1983. The extreme heat wave on 7 February came after another record-setting heat wave 10 days earlier, with Melbourne experiencing three days in a row with maximum temperatures higher than 43°C during 28-30 January, unprecedented in 154 years of Melbourne observations. A remarkable image of the surface temperature anomalies associated with this heat wave is available from the NASA Earth Observatory.

Increases of mean temperature and mean maximum temperature in Australia have been attributed to anthropogenic climate change, as reported in the IPCC Fourth Assessment, with a best estimate of the anthropogenic contribution to mean maximum temperature increases of about 0.6°C from 1950 to 1999 (Karoly and Braganza, 2005). A recent analysis of observed and modelled extremes in Australia finds a trend to warming of temperature extremes and a significant increase in the duration of heat waves from 1957 to 1999 (Alexander and Arblaster, 2009). Hence, anthropogenic climate change is likely an important contributing factor in the unprecedented maximum temperatures on 7 February 2009.

Relative humidity: Record low values of relative humidity were set in Melbourne and other sites in Victoria on 7 February, with values as low as 5% in the late afternoon. While very long-term high quality records of humidity are not available for Australia, the very low humidity is likely associated with the unprecedented low rainfall since the start of the year in Melbourne and the protracted heat wave. No specific studies have attributed reduced relative humidity in Australia to anthropogenic climate change, but it is consistent with increased temperatures and reduced rainfall, expected due to climate change in southern Australia.

Wind speed: Extreme fire danger events in south-east Australia are associated with very strong northerly winds bringing hot dry air from central Australia. The weather pattern and northerly winds on 7 February were similar to those on Ash Wednesday and Black Friday, and the very high winds do not appear to be exceptional nor related to climate change.

Drought factor: As mentioned above, Melbourne and much of Victoria had received record low rainfall for the start of the year. Melbourne had 35 days with no measurable rain up to 7 February, the second longest period ever with no rain, and the period up to 8 February, with a total of only 2.2 mm was the driest start to the year for Melbourne in more than 150 years (2). This was preceded by 12 years of very much below average rainfall over much of south-east Australia, with record low 12-year rainfall over southern Victoria (2). This contributed to extremely low fuel moisture (3-5%) on 7 February 2009. While south-east Australia is expected to have reduced rainfall and more droughts due to anthropogenic climate change, it is difficult to quantify the relative contributions of natural variability and climate change to the low rainfall at the start of 2009.

Although formal attribution studies quantifying the influence of climate change on the increased likelihood of extreme fire danger in south-east Australia have not yet been undertaken, it is very likely that there has been such an influence. Long-term increases in maximum temperature have been attributed to anthropogenic climate change. In addition, reduced rainfall and low relative humidity are expected in
southern Australia due to anthropogenic climate change. The FFDI for a number of sites in Victoria on 7 February reached unprecedented levels, ranging from 120 to 190, much higher than the fire weather conditions on Black Friday or Ash Wednesday, and well above the “catastrophic” fire danger rating (1).

Of course, the impacts of anthropogenic climate change on bushfires in southeast Australia or elsewhere in the world are not new or unexpected. In 2007, the IPCC Fourth Assessment Report WGII chapter “Australia and New Zealand” concluded

An increase in fire danger in Australia is likely to be associated with a reduced interval between fires, increased fire intensity, a decrease in fire extinguishments and faster fire spread. In south-east Australia, the frequency of very high and extreme fire danger days is likely to rise 4-25% by 2020 and 15-70% by 2050.

Similarly, observed and expected increases in forest fire activity have been linked to climate change in the western US, in Canada and in Spain (Westerling et al, 2006; Gillett et al, 2004; Pausas, 2004). While it is difficult to separate the influences of climate variability, climate change, and changes in fire management strategies on the observed increases in fire activity, it is clear that climate change is increasing the likelihood of environmental conditions associated with extreme fire danger in south-east Australia and a number of other parts of the world.

References and further reading:

(1) Bushfire Weather in Southeast Australia: Recent Trends and Projected Climate Change Impacts, C. Lucas et al, Consultancy Report prepared for the Climate Institute of Australia by the Bushfire CRC and CSIRO, 2007.

(2) Special Climate Statement from the Australian Bureau of Meteorology “The exceptional January-February 2009 heatwave in south-eastern Australia”

Karoly, D. J., and K. Braganza, 2005: Attribution of recent temperature changes in the Australian region. J. Climate, 18, 457-464.

Alexander, L.V., and J. M. Arblaster, 2009: Assessing trends in observed and modelled climate extremes over Australia in relation to future projections. Int. J Climatol., available online.

Hennessy, K., et al., 2007: Australia and New Zealand. Climate Change 2007: Impacts, Adaptation and Vulnerability. Contribution of Working Group II to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change, M.L. Parry, et al., Eds., Cambridge University Press, Cambridge, UK, 507-540.

Westerling, A. L., et al., 2006: Warming and Earlier Spring Increase Western U.S. Forest Wildfire Activity. Science, 313, 940.

Gillett, N. P., et al., 2004: Detecting the effect of climate change on Canadian forest fires. Geophys. Res. Lett., 31, L18211, doi:10.1029/2004GL020876.

Pausas, J. G., 2004: Changes In Fire And Climate In The Eastern Iberian Peninsula (Mediterranean Basin). Climatic Change, 63, 337–350.

399 Responses to “Bushfires and extreme heat in south-east Australia”

  1. 1
    David Horton says:

    Good summary David. It is clear that the denialists are running scared on the fires, determined not to let people see that here is another of the kind of direct impacts on people and society that climate change will bring. A small point – you say that the strong winds are not obviously linked to climate change, but are they not indirectly linked through the high temperatures on land creating a bigger temperature differential between land and sea?

  2. 2
    taust says:

    A very considered response.

  3. 3
    Johnno says:

    This seems to lay to rest media comments that it was a one in a hundred year event. I’m somewhat troubled by the level of mawkish introspection it has generated such as this weekend’s National Day of Mourning. That emotional intensity should perhaps be redirected at restoring Australia’s Emissions Trading Scheme to a cut of 25% by 2020, not the feeble 5% cut. Hopefully adaptation measures will lessen the severity of the next round of firestorm conditions. On top of water supply woes surely the government will now take bigger climate mitigation steps as well. If not then we have learned nothing.

  4. 4
    Ark says:

    Very convincing! Strong point is that the analysis is based on a 40-year old danger scale. I’m tempted to say “hard to deny” but that sounds a bit like “bring ‘m on”.

  5. 5
    Jim Galasyn says:

    Thank you for this summary. I’ve been calling the Victoria fires the first climate-change disaster of the 21st century. Now I have a quick, thorough summary to link to.

  6. 6
    Former Skeptic says:

    IMO a good summary of the causes underlying a terrible event. I have my doubts, however, about applying UHI to explain maximum temperatures as it is generally a nocturnal phenomenon affecting minimum temperatures instead.

  7. 7
    PHE says:

    One important contributary factor to the tragedy you have not mentioned is: ‘building homes in eucalyptus forests’. As is well known, the trees emit flammable oils, also contained in their leaf litter. Whatever the cause, it is inevitable that eucalyptus forests will burn from time-to-time. I don’t know about Victoria, but certainly in northern Australia, bush fires are a routine annual site. Many start naturally, and if they don’t the authorities start them deliberately (obviously in a controlled manner). The reasoning is that the longer a forest goes without fire, the worse it will be – and it will happen some time. The same is true for southern California. Building homes in such forests, and hoping nature won’t take its course is analgous to building homes on floodplains – a common practice in the UK in recent decades, and hence why with every big flood we see TV film of flooded new homes. This observation has nothing to do with whether or not climate change is a factor, but helps to explain why this was such a tragedy in human terms.

  8. 8
    duBois says:

    There’s a tendency to sequester the Urban Heat Island Effect as if the heat that urbanization adds to the mix somehow doesn’t count. Can someone give us a rough sense of scale here. UHI raises global temps 10%? 1%? .1%? .01%? as much as GHGs. Or even less?

  9. 9
    Joe Horvath says:

    I am reluctant to attribute any single event to climate change. This is consistent with the IPCC regional projections and our understanding of what AGW is going to bring to this part of the world, however I think that PHE is right – building homes in eucalypt forests is asking for trouble. Ridge lines are great for a view, but not so good when it comes to bushfires, particularly when embers were starting fires 5-10km ahead of actual fire lines. The stay and defend policy in extreme bushfire conditions has to be questioned, as is the failure to implement effective hazard reduction programs over winter/spring.

    I just think we need to be careful ascribing any single event to climate change, particularly given that we tend to jump on deniers who point to any exceptionally cold events (as have occured in Europe and the US this winter) as evidence against AGW.

  10. 10
    Jim Galasyn says:

    PHE, let’s not forget the immense toll on wildlife: Animal death toll from Australia bushfires may be in the millions.

    Much of the formerly forested habitat will never recover and will be replaced by savannah, so many animal populations will have no path to recovery.

  11. 11

    I would so love this to be published in the Sydney Morning Herald as a riposte to Miranda Devine’s recent piece blaming the fires on “greenies”.

  12. 12
    Luke says:

    The 12 year drought sequence leading up to fires is seen to be a contributing factor. A recent review by Nicholls in Climate Dynamics (Jan 2009) “Local and remote causes of the southern Australian autumn-winter rainfall decline, 1958–2007” attributes much of the rainfall decline over southern Australia to changes in the Southern Annular Mode (which have both both greenhouse and stratospheric ozone depletion related drivers). However other recent research has also pointed to changes in the behaviour of the Indian Ocean Dipole (Ummenhofer) and Walker circulation (Smith & Power, Vecchi)

  13. 13
    Former Skeptic says:

    #8 duBois:

    Try reading the IPCC AR4 SPM as p.5 has your answer.

    “Urban heat island effects are real but local, and have a negligible influence (less than 0.006°C per decade over land and zero over the

    By contrast, and in the same page of the SPM, the linear warming trend over the last 50 years from 2006 is 0.13°C (between 0.10°C to 0.16°C) per decade.

  14. 14
    Brian Cockrell says:

    Folks, fuel moisture can be tinderbox dry but unless you have the appropriate fuels conditions, there is no fire danger. Just like in the western US, the issue of wildland/urban interface must be examined. If you want to attribute the catastrophe to AGW (while refusing to acknowledge any of the northern hemisphere’s corresponding cold weather) go ahead. But perhaps one should be looking at the simpler issue of fuels reduction and people living where perhaps they shouldn’t. Smaller, more frequent fires prevent catastrophes like this.

  15. 15
    Joe Hunkins says:

    David although this data point and the trends study you cite seem very consistent with AGW:

    … anthropogenic contribution to mean maximum temperature increases of about 0.6°C from 1950 to 1999…

    Your follow up statement confused me:

    Hence, anthropogenic climate change is likely an important contributing factor in the unprecedented maximum temperatures on 7 February 2009.

    Wouldn’t it be best categorized as a trivial or unimportant contributing factor? Without AGW wouldn’t we probably still see all these record temps and dryness in Australia – they’d just be a fraction of a degree less?

  16. 16
    Andrew Watkins says:

    I’m having a mental blank here, but i am pretty sure i have read a paper that suggested that the UHI is not linear with temperature, and that at temp extremes it has little influence.
    In Melbourne on that day, with 80kmh winds, I also suspect this “flushing” of the air would also have reduced any UHI effects. The fact that Laverton (~30km SW from Melbourne), also on the edge of Port Phillip and in open grassplains recorded 47.9degC suggests little influence of UHI.

  17. 17
    Nathan says:

    It’s interesting to contrast the heat and fires in VIctoria and South Australia with the flood events in Queensland that happened at the same time. I think CSIRO research had suggested this condition would bemore frequent (bush fires and heat waves in the south and flooding in the north) – it seems Australia can’t win with AGW.

  18. 18
    David B. Benson says:

    Joe Hunkins (15) — I suggest reading

  19. 19
    dhogaza says:

    If you want to attribute the catastrophe to AGW (while refusing to acknowledge any of the northern hemisphere’s corresponding cold weather) go ahead.

    Read more closely.

    1. The piece doesn’t attribute the catastrophe to AGW but rather attempts to outline the possible contribution AGW has made to the conditions that helped the fire grow so intense so quickly.

    2. The northern hemisphere’s cold weather isn’t “corresponding”, because the piece is outlining *trends* which have been attributed to AGW by the most recent IPCC report. What is being seen in Australia is not simply a weather event.

    3. Speaking of the northern hemisphere’s cold weather, I live in the northern hemisphere, and we’re not having a cold winter where I live. Get your non-facts right, at least.

  20. 20
    Hank Roberts says:

    Joeduck (Hunkins) — you’re mixed up. You seem to be confusing the change in the average with the change in the extreme. That’s illustrated here:

    “Schematic illustrating the disproportionate effect on extreme and record temperatures when the mean temperature increases, for a normal temperature distribution.”

  21. 21
    Greg Simpson says:

    Wouldn’t it be best categorized as a trivial or unimportant contributing factor?

    We’re told that the FFDI was 120 to 190 in some locations. Now if someone could just calculate what it would have been at a temperature of 0.6 (or maybe 0.7) less then we would perhaps have a better idea if it was trivial or important.

  22. 22
    Timothy Chase says:


    In order to perpetuate the myth that scientists were expecting an ice age back in the 1970s, George F. Will engaged in the sort of quote-mining today that would shame a staunch young earth creationist — and Nate Silver of FiveThirtyEight called him on it…

    Will Omitted Key Context in Ice Age Quote
    Monday, February 16, 2009
    Nate Silver

    Neat to see a blog that isn’t devoted to climatology calling people on this nonsense.

  23. 23
    Al Breingan says:

    Re #11 Miranda Devine’s b*****t
    The only way you will get any change is to email her and SMH and complain (as I have done) plus suggest this link.

    We need to get out more, and push as hard as is reasonable.

    Unfortunately we have a short attention span to deal with, so, as nasty as it feels we should use the current shock and grief to make our point while we may have some effect.

  24. 24
    Dan Hughes says:

    re: #23

    There’s some real science on Real Climate:

    Unfortunately we have a short attention span to deal with, so, as nasty as it feels we should use the current shock and grief to make our point while we may have some effect.

  25. 25
    Andrew says:

    Re #14: “any of the northern hemisphere’s corresponding cold weather”

    According to the National Climate Data Center, so far this winter, Northern Hemisphere land surfaces have been above the 1961 to 1990 average:

    December 0.69 C above
    January 1.05 C above.

    Northern Hemisphere Ocean temperatures have also been above the 61-90 average:

    December 0.37 C above
    January 0.33 C above.

    The Southern Hemisphere land has been above the 61-90 average:

    December 0.61 C above
    January 0.46 C above

    The Southern Hemisphere ocean temperature have also been above the 61-90 average:

    December 0.45 C above
    January 0.45 C above.

  26. 26
    Ray Ladbury says:

    Greg Simpson–you are confusing the global change with the local change. A change of 0.7 degrees globally could mean 3 degrees at higher latitudes. Of course if you looked into the science at all, you would have known that.

  27. 27
  28. 28
    herbert stencil says:

    It seems that on 7 February, some areas of Victoria experienced conditions that were extremely intense on all the factors identified by Professor Karoly. Last night on Four Corners there was an excellent program on the fires

    In his discussion above, Professor Karoly remarks that >50 on the Bush Fire Danger Index (where 100 represents the conditions experienced on Black Friday in 1939) represents “extreme” fire danger. A commentator working with the Index remarked on the Four Corners program that the index had exceeded 200 in some areas!

    A very experienced bush fire brigade fireman remarked that conditions were far more intense than they had ever experienced previously due to a confluence of events. The program includes footage of the fires in full flight. And the pictures are truly terrifying.

    What is clear is that temperatures in and around the fire must have been very high indeed – of the order of several hundred degrees C I would guess, perhaps more. There is footage of houses simply exploding into flame when the fire came. It is easy to see that anyone caught close to such intense fire could not have survived.

    It seems evident that the leave early or stay policy was based on experience of much less intense fires where there is time to stay in the house and let the fire pass, then go out and put the spot fires out. Based on this experience it is evident that the conditions when such a fire is raging are so intense that it is folly to stay, unless one has an underground bunker, with separate air supply, to retreat to. One of the issues mentioned frequently is that the fire consumed all of the oxygen in the air, making it impossible to breath.

    On that same day I was in the country in NSW, on a day where the air temperature where we were was 38 Deg C. We tend to think of that number as a measure of how hot it is. However, on that day I was using a laser temperature device to measure the temperature of the ground. Readings ranged from 55 deg C to 65 deg C. A tyre in the direct sunlight recorded 75 deg C.

    We know that high air temperatures are associated with low humidity. It is easy to see that if the air temperature is in the mid 40s, that the temperature of the detritus on the ground in direct sunlight could be around 70 deg C, which makes it evident that any moisture present would soon evaporate. Obviously these conditions are conducive to rapid ignition, and the fuel loads were such that intense fires developed, especially on the upslopes rising to the south, where the fires had that strong wind behind them.

    Another point made was the incredible rate at which the fires advanced across the landscape. The winds were blowing burning embers from the fire ahead of the fire, and lighting spot fires a kilometer or two ahead of the main fire front. Add to that that when the fires merged, there was a fire front extending over 100km, and you can see what the fire crews were trying to deal with.

    As to answers, I think that the main issue is a town planning issue. Clearly the construction of vulnerable houses in close proximity to eucalypt (or pine) forest is highly dangerous. I think it is evident that one conclusion will be that no new house can be built within, say, 100m of the edge of the eucalypt forest. It would also help (in the long run) if householders were required to eliminate flammable species within 100m of houses, and instead plant deciduous trees that provide some barrier to fire – oaks, elms, ashes, linden, maples etc.

  29. 29
    Lawrence Coleman says:

    I’ve been following the fires very closely and the factors leading up to the disaster. Victoria and South Australia had in affect more that 10 straight fact almost two who whole weeks (13days) of temps in the high 30Cs to mid 40Cs. By far the longest continuous heatwave in our recorded history. Parts of Victoria on that Saturday were up to 48C. As mentioned above the Forest fire danger index had never gone above 70..Ash Wednesday. The weather conditions and danger index for the recent fires were between index 150 – 200. A couple of fires may have been lit by arsonists but with those tinder dry conditions and extreme heat anything could have set the fires off. Several fires that killed 100 people or more were started by a downed power line due to the extremely high northerly winds. Even lawns were catching alight and exploding so the argument that this was made worse through green party involvement is fallacious. The ember attack radius was many hundreds of meters in front of the fire-front. Even houses with no trees around them went up. What gave rise to the disaster was a combination of unprecedented low humidity, a record long drought, the longest heatwave in our recorded history, the highest temps ever recorded for Melbourne and Adelaide. And the speed of the dry/hot northerly winds.
    What should have been done in hindsight was the clear the vegetation on the sides of roads to at least one tree length. To allow cars to pass even if trees were downed. The speed of the fires was also unprecedented so warnings had little effect. Hope this sheds more light on the subject.

  30. 30
    Jim Galasyn says:

    60 Minutes: The Age Of Mega-Fires.

    “You know, there are a lot of people who don’t believe in climate change,” Pelley remarks.

    “You won’t find them on the fire line in the American West anymore,” Tom Boatner says. “‘Cause we’ve had climate change beat into us over the last ten or fifteen years. We know what we’re seeing, and we’re dealing with a period of climate, in terms of temperature and humidity and drought that’s different than anything people have seen in our lifetimes.”

  31. 31
    GlenFergus says:

    #7, #9:

    Blaming “building homes in eucalyptus forests” is highly misleading. Downtown Marysville is not in any sense in a eucalypt forest, though there is such forest less than a kilometre away, as there is in many Australian small towns. Your recommendation, perhaps, ought to be, “Best not live anywhere in SE Australia in a century of rapid climate change”?

  32. 32
    Craig Allen says:

    Dr Karoly,

    If you have the data for the FFDI index values since Black Friday in Victoria, would you be able to plot it for us please.

    By the way, that ABC television debate last year in which you caned Bob Carter and the La Rouchian audience stooges was a hoot. I was watching with a bunch of friends cheering you on like we were at the football. You should do more TV. We concluded that there should be a charming geek of the year award.

    [Response: FFDI data for a number of sites is SE Australia is available since 1970 in reference 1, which you can download. I don’t have the data to calculate FFDI for 1939 but it was done by MacArthur and is available from the Bureau of Meteorology in Australia. Not sure whether I should do more TV, but you can find some recent stuff on ABC Lateline in Oz. Also, not sure whether it is Nerd of the Year or Geek of the Year. – David Karoly]

  33. 33
    Bruce says:

    I would like to see some forestry expert give quantitative input on the fuel buildup. This was alluded to but not quantified in #14, #28, and #29. Fuel buildup doesn’t seem to be covered by the FFDI. I’ve seen commentary that the fire was so bad because “environmentalists” had worked too hard to prevent fires, so this is an aspect that needs to be dealt with.

  34. 34
    Ricki (Australia) says:

    Thanks for the great article.

    I agree with most of the statements in 28, a good addition to the debate.

    1: following such a protracted drought, major bushfires in Vic were to be expected, it was just a matter of time (all Ozzies would understand this).

    2: the intensity of the fires when they came was unprecedented (up to 200 index is just staggering) and we will have to modify the way we live now that we know it can get that bad. I live near Sydney and we are considering building a bunker as a shelter (large diameter pipe in the ground).

    3: It is almost impossible to find a house anywhere in Oz that is more than 100m from eucalypts. Mostly they exist in all cities and suburbs. In fact Canberra (where they have a lot of deciduous trees by the way) was hit a couple of years ago — mostly it was ember attack from big fires some kms away and lots of houses were lost.

    4: In my opinion, climate change has contributed to the extended drought across SE Oz over the last 12 years and so has to bear some of the blame for what happened. Personally, I am doubtful if Australia will ever return to the wetter times of the 50s and 60s.

    5: I agree that we cannot say AGW CAUSED the fires (clearly not) but it is patently clear that we will get more bushfires and more intensity of fire in the future as global temperature continues to rise.

  35. 35
    Brian T says:

    In Melbourne on Saturday, the City centre was one of the “cooler” places. Where I live in a leafy SE suburb, it was 0.5C hotter, as it was in most other suburbs. There was no UHI effect. Even in town, the weather was ominous, frightening, even.
    As far as the actual weather that caused the fires, it’s rubbish to talk about 0.6C cooler or hotter. The problem is that we are having more very extreme (very hot) days, as predicted, not just that every day is 0.6C warmer. Also, our annual rainfall (over the last last 10-12 years) is 2/3 of the long term average.
    We’re living with climate change but nobody is doing anything about it! We have some of the least efficient electricity generation anywhere and nobody wants wind farms – “spoils the view”.

  36. 36
    Craig Allen says:


    As an environmentalist in Victoria, I take umbrage at the scapegoating of people who care and advocate for wise environmental stewardship. In addition to the terrible human suffering, this and previous extreme fire events have been a disaster for our forest ecosystems. The lack of burning is due in great part to inadequate resourcing of the Natural Resources and Environment department, Parks Victoria etc. They have been doing as much as conditions and their resources allow. And I note that they have copped a great deal of criticism for fuel reduction burns that in the past have escaped containment lines.

    Too frequent fire regimes are ecologically damaging, as are fires that are too hot. They reduce ecological diversity, eliminate fauna populations and can push the vegetation mix toward more flammable, faster growing species.

    For the benefit of both the environment and people, we need more burn-offs and these need to be conducted with more concern for ecological impact. This will require a lot more resources (both people and equipment) than is currently put into the effort.

    Another difficulty for conducting fuel reduction burns is the construction of homes and assets in the bush, and the increased establishment of plantations. This increases the risk that prescribed burn-offs will occasionally get away, damage property and possible cause casualties. A tragedy caused by a burn-off gone wrong is far more politically damaging than a tragedy cause by a wildfire. So the balance of risks is being weighted toward wildfire (high impact but able to be blamed on weather and criminals) and away from burn-offs which will occasionally go wrong (and for which blame can be laid at the feet of individuals and organisations).

    These fires are extinction events. The vegetation clearances in order to reduce fire risk which will inevitably will come next will increase the fragmentation of our already fragmented woodlands and forests and will push further species beyond the brink. We have lost a great deal. We will lose a great deal more before this is over. If only the resources had been adequately devoted to managing our environment in preparation for this …

  37. 37

    Nice article.

    One thing I found completely bizarre was the widespread attempt at pinning the whole thing on environmentalists and “green” politicians. The Greens as a party are not in power anywhere that I know of on the mainland, and at least one story I found about Greens policies in New South Wales on some other a blog was an outright lie. Probably all of this was a preemptive strike to get in before anyone attempted to link the whole thing to global warming. The Australian, that trade journal for loggers and coal miners, was particularly strong on attributing causes to environmentalists and greenies, including a vicious slur on the Wilderness Society. I personally know of no one who attempted to make a big deal of the climate change link in part because of the uncertainties raised here, but also because it would have been spectacularly indecent to make political capital while thousands of people were coping with losing everything, and the death toll was heading towards 200.

    A few other factors… poorly managed preventive burning increases the flammability of the system. First, fire-adapted plants burn hot and fast to wipe out competition, then grow back strongly, making the next fire worse. A fire management regime that fails to take this into account is more dangerous than doing nothing. To compound the problem, African grasses brought in to improve grazing (plus some escapes from things like packing materials) are not only highly fire-adapted but have no natural predators. This means they grow out of control once they take over after a fire. In addition, much leaf litter decomposition in Australian forests is by larvae of small moths and beetles that lack the mobility to escape a fire. A very large fire and frequent fires in the same spot means these insects don’t do their job, and the leaf litter adds to the fuel load. Micro-mosaic burning is one way to mitigate these problems: you don’t burn a patch of more than 3ha (around 7.5 acres). These patches break the fire front, but aren’t big enough to sterilize the area of less fire-adapted vegetation and relatively immobile insects.

    More on fire management strategy as applied to Queensland, but of general interest I hope, at my campaign blog.

    Captcha: counter midget (I like).

  38. 38
    David Horton says:

    Craig Allen
    “For the benefit of both the environment and people, we need more burn-offs”. No, we don’t. This simplistic view is being promoted by the Gang of Fire, whose ideology involves complete management and exploitation of all forests by humans, and “prescribed burning” is an important part of this. prescribed burning, at the rate they call for (one was demanding TEN times (!) the current rate last week) would cause massive extinctions, loss of biodiversity, extensive damage to the well-being of forests, would not prevent fires, and indeed may actually (by changing species composition) increase the risk of fires. If you want to use it because you think it will form an effective fire break around towns then go for it, but beyond that you are damaging the environment you are purporting to save. Incidentally before you tell me the popular mythology, yet again – Aborigines didn’t do anything like prescribed burning, didn’t manage the environment with fire, and consequently didn’t cause the extinction of small animal species, or change the composition of habitats. Some references are here – and

  39. 39

    Is Victoria the same area of Australia where wheat is or was grown? I read somewhere else, but I don’t remember where right now, about the wheat farmers having trouble and rivers running dry in Australia. Maybe that was the other southern Australian province. With the rivers dry, there would be no way to irrigate that I know of. I was hoping that the article would talk about the farm production in Australia because lack of food is what will impact everybody soon. General references to desertification:
    Steve Chu, the new Secretary of Energy, made some remarks about the impending end of farming due to desertification in California.

    I don’t believe farmers can just move north in the northern hemisphere because the soil will be different even if [a big if] the temperature and rainfall will be right for farming. The Australians can’t move south because there is nothing but ocean to the south. In the northern hemisphere, I doubt that melted tundra would be anything like rich Iowa soil. Canada has a huge area of forest, but is it really going to be cut down to make farms? How long will that last before that area also becomes desert?

    RealClimate, could you do an article on what is happening to the food supply?

  40. 40

    I’m glad you wrote this piece. Ever since the fires my opinion has been that they COULD have been a result of increased global warming but also MAY be simply a once in 200 year event.

    One horrible and major fire is not enough to prove anything. An increase in bushfires over a relatively short period of time (in this case, 10-20 years) would be far more indicative of claimte change affecting the Australian environment.

  41. 41
    dhogaza says:

    To compound the problem, African grasses brought in to improve grazing (plus some escapes from things like packing materials) are not only highly fire-adapted but have no natural predators. This means they grow out of control once they take over after a fire.

    Cheatgrass (from the eastern European steppes). US. Sigh.

    Though it wasn’t brought in to improve grazing (rather, to “cheat” seed and grain shipments). But it has altered the fire ecology of much of the Western US immensely. More frequent, earlier, hotter burns than anything on the prairie co-evolved with.

  42. 42
    MarkB says:

    Off topic…any thoughts on the recent comments by Chris Field? How likely are the various feedbacks mentioned on this articles? Is progress being made in understanding if and when these feedbacks will occur and the magnitude of them?

  43. 43
    Thomas says:

    37: I don’t find efforts to blame it on environmentalists at all surprising. That is just what we see here in the USA whenever there is a bad fire. Often logging interests who were denied timber rights are the culprit.

    If climate change is making dryness and heatwaves more common, wouldn’t we expect that given time to equilibrate, that the mix of vegetation would become less flamable. If so, perhaps longterm the fire danger may not change by much. If forests are being replaced by grasslands, that could be thought of as part of that process.

    I do think we have an attribution problem. Because we know it is impossible to attribute any single event to CC, we always end up answering no! This resembles the problem of blaming a patients cancer on environmental toxins. At best we can only probablistically answer the question. Unfortunately, this tends to let the guilty of the hook. In the case of AGW, it gives the deniers an out. Is it possible we shouldn’t say no, we can’t prove it, but the probablity that this event was caused by AGW is X%? Or is that considered to be a PR no-no?

  44. 44
    Joe Hunkins says:

    Thx for links Hank and dhogza – the BraveNewClimate article helps explain the rationale for an AGW link here in addition to the obvious most important likely “cause” of arson.

  45. 45
    Harold Pierce Jr says:

    Go over to WUWT and read the sad story of a home owner, who removed 247 trees out of thousands on his property to create a fire break around his house, ended costing him $100,000 fighting city hall for violating local bylaws against cutting down trees. His house was the only one left standing within a several miles or so radius. He puts the blame squarely on the enviros who were successful in convicing local gov officials not to conduct controlled burns to remove fuel litter and to enact bylaws prohibiting removal of any trees on a home owners property.

  46. 46
    John A. Davison says:

    It is hard to believe that there are still those who adamantly refuse to believe that man is the primary cause of these drastic climate changes.

  47. 47
    anna says:

    it is difficult to convey just how disturbing it is to have a persistent smoke haze hanging over the city that you live in. it is made all the worse by the brown grass and exposed dirt on the nature strips and in the parks, the falling brown leaves on the trees, almost two months before autumn starts, the blackened and shriveled leaves on other plants. i should note that i live a few kilometres out from the melbourne CBD, nowhere near the fires and the devastation they’ve caused, but it is still so viscerally apparent that something is wrong.

    i’ve known about global warming/climate change since i was eight years old (1988). i was frankly quite worried by it but had faith that ‘the adults’ would make sure nothing bad happened. what has become increasingly apparent over the years is that ‘the adults’ are in the majority short-sighted ditherers who are willing to take the biggest risk possible with the one and only habitable planet we have.

    i find it hard to listen to kevin rudd talk about the bushfires in light of his radically irresponsible 5% emission reduction target, or to listen to john brumby (premier of victoria) talk about prevention after his government allowed the most carbon intensive power plant in the developed world to continue operating until 2031, when it was supposed to be decommissioned in 2009. i very much doubt the sincerity of their emotion and commitment.

    david, i know you are the chief climate adviser to the victorian government, but it seems that they’re not listening to you.

    vale to the dead, 200 as of today.

  48. 48
    Paul says:

    A point i would make is that many ‘amateur’ denialists in the UK and other places in the ‘Northern Hemisphere’ have used the cold weather (snow) as an excuse to come out and say we have a cooling phase.

    This is just as crazy as blaming fires in Australia on global warming.

    They basically exploit peoples obsession with local weather and self interest. However the heatwaves in Australia (not the fires) have helped to highlight the seasons in the different parts of the world and that global warming is literally a global climate issue.

  49. 49
    Sekerob says:

    Is the UHI moniker the proper description of the Urban Island effects on temperature. Should they not be named UTI instead? The effect works both ways depending on the surrounding land features I’d think.

  50. 50

    Edward, your point that “In the northern hemisphere, I doubt that melted tundra would be anything like rich Iowa soil,” is correct. WRT “Canada has a huge area of forest, but is it really going to be cut down to make farms?” the short answer is no–Canadian shield terrain is extremely rocky, with little arable soil. Trying to farm there is so patently a plan to go broke fast that no-one will try. What’s growing there now is what is adapted to do so, and is slowly producing good soil–in a few tens of millenia it may be time to think about farming there.

    OneSalient, read the papers given as references–they *are* such attribution studies. I was interested in the Canadian study, so will cite it:

    “Here we show first that human emissions of greenhouse
    gases and sulfate aerosol have had a detectable
    warming effect during the fire season in the fire-prone
    regions of Canada, and second, applying a statistical model
    to simulated temperature changes, we demonstrate that
    human-induced climate change has had a significant effect
    on the area burned by forest fires in Canada.”