Guest essay by Pasi Autio 2.2.2020
The Australian bushfire season of 2019-2020 is now the climate topic of the year – the severe bushfire season has caused more than 2000 houses to burn in the state of New South Wales (NSW) alone. At least 34 people have died and likely over 1 billion mammals, birds and reptiles has been lost (1).
According to wikipedia pages for the 2019-2020 bushfire season (2) 18.9 million hectares of land has been burned as of 14h of January. This sounds severe, but how large is the amount of burned land when comparing to the earlier seasons?
Annual burned area in Australia
There are sources to place this bushfire season in the context like the study by Giglio at al 2013 (3). The paper describes a fourth generation Global Fire Emissions Database (GFED4). This data set combines satellite records like the 500m MODIS burned area maps with active fire data from the Tropical Rainfall Measuring Mission (TRMM) Visible and Infrared Scanner (VIRS) and the Along-Track Scanning Radiometer (ATSR) family of sensors. The paper also provides burned area data for Australia and New Zealand (combined) for the years 1997-2011.
Luckily Louis Giglio and his team have continued to work and have created excellent source of all burned area and fire-based emissions datasets.MODIS Collection 6 (C6) MCD64A1 burned area dataset (4) provides satellite-based burned area data for all continents – and also for Australia.
The data is available at globalfiredata.org with a great analysis tool available in the same address. Currently the dataset provides burned area data for the years 1997-2016. It’s possible to select a continent or country and choose several options about the source data from emissions to burned area (among others).
Let’s start with burned area data for Australia:
Figure: Annual burned area in millions of hectares
Figure provides the total burned area for each year between 1997 and 2016 in millions of hectares. Area burned every year was between 18.2 million hectares (2010) and 94.6 million hectares (2001). On average, the area burned during this time period was 52.9 million hectares. Since there is 769 million hectares of land in Australia, the area burned between 1997 and 2016 was 2.4 – 12.3 % of total land area – every year.
These figures seem very high but satellite mapping shows which areas were burnt in which year. Let take year 2001 as an example.
Figure: Burned area in Australia for the year 2001
The color of each grid cell presents the percentage of area burned within this grid cell. As we can see the majority of fires are happening within the Australian northern and western territories. But overall, the fires can happen everywhere with the exception of desert in the middle. The reason for lack of fires in the desert is of course obvious: area’s like the Simpson desert have plenty of heat, but little to burn. But if there is sufficient fuel load to burn, the fire seems to be likely at some point.
Thus the area burned so far during the bushfire season 2019-2020 in easy to place in the context: the burned area during this season as quoted by several sources is ~20% of average area burned in Australia annually. It is likely that the quoted area is too low, since the fires in many remote areas are not reported and can be properly identified only with means of satellite observations. The real burned area during this season will eventually be available through satellite burned area datasets.
Most of the burned land areas are shrublands, woodlands and open forests. Forests fires happen mostly within eucalyptus forests (Australia’s northern and eastern shore).
The burned area data provides the details of area being burned in total whether it is forest, non-forest and whether the fire was planned (prescriptive burns) or non-planned. But how about the forests specifically?
Forest fires in Australia
There is another source, which provides a lot of details for forest fires specifically. Australia government’s department of Agriculture provides the “Australia’s State of the Forests Report” for every five year period. The latest one has been published in 2018 (5) and covers years 2011-2016.
This report provides lots of details about forest fires in Australia starting with annual forest fires for seasons 2011-2012 to 2015-2016.
Figure: Annual planned and unplanned area of forest fires in Australia – millions of hectares
Unplanned forest fires where between 8.9 million hectares (season 2013-2014) and 21.2 million hectares (2012-2013). In addition the area burned due the planned (prescriptive) burns was between 6.2 million hectares (season 2013-2014) and 8.2 million hectares (season 2011-2012). Also we can see that this data correlates well with the satellite burned area dataset.
Earlier versions of these reports provides similar figures; for example the year 2008 version of this report says that the estimated area of forest burnt in the period from 2001 to 2006 was 24.7 million hectares; an estimated 20.0 million hectares was burnt in unplanned fires and 4.7 million hectares was burnt in planned fires. In average 15.7% of the Australian forest land burned every year. According to the latest report, the total area of forest in Australia burnt one or more times during the period 2011–12 to 2015–16 was 55 million hectares (41% of Australia’s total forest area) (5). Some forests had at least one fire per year during five different years between 2011 and 2016. Thus, forest was in fire every year.
That is a lot of forest fires in one country. You would imagine that after all these fires there are no forests left in Australia. But there is and according to the “State of forests” report, the area of forest has even increased slightly between 1990 and 2016.
Most of the forested ecosystems in Australia are ecologically adapted to fire and even require it for regeneration. Eucalyptus trees – for example – do not just resist fire, they actively encourage it. Eucalyptus leaves don’t decompose and are highly flammable. Some species for these trees hold their seeds inside small capsules until the fire happens. Fire triggers massive drop of seeds to the ground cleaned by the forest fire (6). Due to the flammable materials generated by Eucalyptus trees, the forest fire in Eucalyptus forest is inevitable sooner or later. Sooner it happens, more controlled the fire is and less harm it will generate to the trees and animals. Avoiding fires too long is clearly not a good idea, but since uncontrolled fires are no good either, there are lots of planned (prescriptive burns) in Australia. Prescriptive burns are the only way of managing the volume of burnable biomass in Australian forests, since removing biomass mechanically is in most cases too labor intensive alternative.
In summary, the Australian bushfire season 2019-2020 overall – despite of all the harm it has caused to lives – both for humans and animals – has not been exceptional on country level. It has not been one of the worst seasons in any metric e.g. not based on area of burned land, burned forests or lost lives.
But there is something special happening in New South Wales in particular.
Fires in New South Wales
Almost all the publicity regarding the 2019-2020 bushfire season in Australia has been related to the fires in New South Wales. And indeed, based on MODIS fire count data from globalfiredata.org there is something extraordinary going in in south-east Australia – especially in New South Wales, where the number of fires detected is about four times higher than in previous records.
Figure: Eastern Australia fire counts (7)
Why the fires are so intense especially in New South Wales?
Positive Indian Ocean Dipole event
Incidentally there is an exceptional natural event going on. An exceptionally positive Indian Ocean Dipole (8) is currently ongoing (9) and has caused severe weather not only in Australia, but in Africa too (10). The event among the strongest in 60 years (12).
Why is this relevant to the extreme fires in south-east Australia? According to the study Cai et al 2009 (11) there is a systematic linkage between positive Indian Dipole events and severe fires in southeast Australia. Almost half of most severe fires have occurred during pIOD.
Some of the studies have tried to link pIOD to the Climate Change, but so far the climate model’s ability to predict the pIOD has been less than optimal (13).
Lack of sufficient prescribed burning
According to studies, the hazardous level of fuel loads can occur within 2 to 4 years from the low intensity prescribed burning in southeast Australia (14). But the prescribed burning practices are not popular among locals. The smoke from the hazard reduction burns is a nuisance and health issue itself (15).
New South Wales has about 20 million hectares of forests and the current level of prescribed burning is ~ 200000 hectares annually. This level of prescribed burning will do little to reduce the risks of catastrophic bushfires.
But one thing is sure: the debate about the right level of prescribed burning will continue (16).
Summary
- All-in-all the bushfire season in Australia is not abnormal
- Consider Australia to be a continent of fire
- Most ecosystems in Australia are ecologically adapted to the fire and will even require it
- The only way to manage the fire hazards in Australia is to manage the fuel loads
- Natural Indian Ocean Dipole events (and ENSO events) have and will have the effect on droughts in Australia
- Hazardous volume of fuel loads together with abnormally positive Indian Ocean dipole and the associated drought is the prime reason for extreme bushfire season in southeast Australia and especially in New South Wales during this season
Further reading
Australia’s state of forests report 1998 provides a lot of background information about the forests and forest fires in Australia in the past.
REFERENCES
- https://www.theguardian.com/australia-news/2020/jan/07/record-breaking-49m-hectares-of-land-burned-in-nsw-this-bushfire-season
- https://en.wikipedia.org/wiki/2019%E2%80%9320_Australian_bushfire_season
- Giglio, L., J. T. Randerson, and G. R. van der Werf (2013), Analysis of daily, monthly, and annual burned area using the fourth-generation global fire emissions database (GFED4),J. Geophys. Res. Biogeosci.,118, 317–328, doi:10.1002/jgrg.20042.
- Giglio, L., Boschetti, L., Roy, D.P., Humber, M.L., Justice, C.O., 2018. The collection 6 MODIS burned area mapping algorithm and product. Remote Sens. Environ. 217,72–85. https://doi.org/10.1016/j.rse.2018.08.005.
- Australia’s State of the Forests Report 2018; https://www.agriculture.gov.au/abares/forestsaustralia/sofr
- https://wildfiretoday.com/2014/03/03/eucalyptus-and-fire/
- 2019-2020 Australian bushfire season; image credit globalfiredata.org; image and all other images used with https://creativecommons.org/licenses/by-nc-nd/4.0/
- http://www.bom.gov.au/climate/iod/
- https://www.abc.net.au/news/2019-05-16/positive-indian-ocean-dipole-bad-news-for-drought-crippled-areas/11120566
- https://www.bbc.com/news/science-environment-50602971
- Cai, W., Cowan, T., & Raupach, M. (2009). Positive Indian Ocean dipole events precondition southeast Australia bushfires. Geophysical Research Letters, 36, L19710. https://doi.org/10.1029/2009GL039902
- https://www.severe-weather.eu/news/unusually-strong-indian-ocean-dipole-australia-europe-fa/
- Cai, W., and T. Cowan, 2013: Why is the amplitude of the Indian Ocean dipole overly large in CMIP3 and CMIP5 climate models? Geophys. Res. Lett., 40, 1200–1205, https://doi.org/10.1002/grl.5020
- Morrison et al 1996, Conservation conflicts over burning bush in south-eastern Australiahttps://doi.org/10.1016/0006-3207(95)00098-4
- https://www.abc.net.au/news/2020-01-08/nsw-fires-rfs-commissioner-weights-in-on-hazard-reduction-debate/11850862
- https://www.abc.net.au/news/2019-12-20/hazard-reduction-burns-bushfires/11817336
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Breaking News.
In the Federal Parliament the PM has just announced there will be a Royal Commission into this summer’s bushfires to be headed by former Air Chief Marshall Mark Binskin.
As well as serving as Chief of the Royal Australian Air Force (2008-2011), he was Chief of the Defence Force from 2014 to his retirement in July 2018.
I think his appointment will be well received.
The Terms of Référence of the Royal Commission will not be settled until all State Premiers have their input.
There have been calls for climate change impacts to be included in such Terms.
We can only await developments.
Just wondering, where does this billion dead animals claim come from?
The article cites The Guardian which could mean anything.
I played around with the numbers based on the 18.9m ha and, assuming my maths is correct, got a density of about 53 animals per ha, or, to flip the units, about 189m2 for every animal.
The extension to this line of thought is what defines an animal in this context?
This ‘billion’ gets thrown around a lot, but I have seen next to no explanation as to what it really means.
Surely the animal death number has to be a trillion by now. In Australia animals are nailed to the ground or tree branches as appropriate (its a tourism thing) so unfortunately the cannot flee even slow moving bushfires.
Its amazing we have any animals at all really in old bushfire areas, I wonder where they come from?
Nick
I’m sorry you have a different view.
My view is that incidents (whatever issue) reported in the media is only a subset of the total type of that incident.
Additionally, the media is likely to focus more on the more newsworthy incidents.
Additionally, I’m sorry you didn’t read the rest of my comments re the amount of burn area in 1974 highlighted by the government source which imo is better than contemporary media
Sorry, haven’t read all the comments, but one thing I’d point out is that the bushfire season isn’t even close to being over. In Western Victoria we had good rainfall over winter, resulting in a lot of growth and wet soil. This has dried out now. Western Victoria has had some some real doozies of fires in the past, including 1983 Ash Wednesday fires, 16th Feb.
So the comparisons in this article are a bit sus. You can’t compare half a season with previous whole seasons.
Sorry Nick
You make no sense.
All fires must be considered in any scientific assessment.
If small spot fires are created from another fire so bit it you can’t ignore it.
Interestingly, the royal commission investigated a very small fire that caused minimal damage and no loss of life.
But many people including myself (and of course the royal commission) understand that the upper Ferntree Gully fire was a extremely significant event. This fire was brought under control with seconds to spare before it engulfed the Dandenong ranges.
I tried to figure out what are the real outcomes of this story. I am sorry but I could not find any reliable figures about the season 2019-2020 fires statistics. One reason is that this season is not over and there are no reliable statistics available.
There were misleading numbers about the burned area: sometimes the figures were in comparison to the forest area and sometimes to the total land area.
There is a great mismatch in these figures:
1. On average 15.7% of the Australian forest land burned every year.
2. Thus the area burned so far during the bushfire season 2019-2020 in easy to place in the context: the burned area during this season as quoted by several sources is ~20% of average area burned in Australia annually.
The conclusion of this story is that the season 2019-20 has been only 20 % about the average season. Sorry, but I do not believe it. Just common sense.
There are some figures about the burned forest areas but I could not find any numbers for this season.
My final conclusion is this: This story is premature because there is no reliable statics of the season 2019-20.
Unfortunately I submitted the early version of the text to WUWT. The final one contains updated figures and text. For example:
The original was:
“Thus the area burned so far during the bushfire season 2019-2020 in easy to place in the context: the burned area during this season as quoted by several sources is ~20% of average area burned in Australia annually. It is likely that the quoted area is too low, since the fires in many remote areas are not reported and can be properly identified only with means of satellite observations. The real burned area during this season will eventually be available through satellite burned area datasets.”
This should read:
“Thus the area burned so far during the bushfire season 2019-2020 can be placed into a context. The burned area as quoted by several sources (~ 18.9 million hectares) is ~36% of average area burned annually in Australia and exceeds the minimum burned area year in the satellite dataset (year 2010). Thus, it is likely that the quoted area is too low, since the fires in many remote areas are not reported. The real burned area during this season will eventually be available through satellite burned area datasets.”
The final version of the text is available at:
https://faktantarkistus.blog/2020/01/12/australian-bushfire-season-2019-2020-severity-reasons-and-conclusions/
Charles, if you could update the story from the link above, I would be more than happy. Thanks! And sorry about the inconvenience.
Updated text also mentions credits to Jo Nova, who provided valuable feedback and comments from Australian perspective.
Antero
Good comment.
It is not fully clear to me. But the area is clearly not unprecedented.
Yes The state of NSW seems to broken its previous record of 4.5 million hectares to be now over 5 million. My state Victoria has only had 1.5 million hectares.
But the Northern Territory has ONLY had 6 million hectares burnt.
The total so far is estimated at 20 million hectares for the whole country.
As dr Roy Spencer highlighted 1974 had 117 million hectares burnt.
While the actual numbers will take time to be tallied 20 million is clearly less than 117 million
Unfortunately old version of the essay from the start of January was sent out. The text should read:
“Thus the area burned so far during the bushfire season 2019-2020 can be placed into a context. The burned area as quoted by several sources (~ 18.9 million hectares) is ~36% of average area burned annually in Australia and exceeds the minimum burned area year in the satellite dataset (year 2010). Thus, it is likely that the quoted area is too low, since the fires in many remote areas are not reported. The real burned area during this season will eventually be available through satellite burned area datasets.”
I also ran a monthly cumulative report of Australia’s burned area for years 1997-2016 from globalfiredata.org. According to this data the fires between January and March in Australia have been really minor compared to all other months. Thus, assuming 18.9 Million hectares from early January is correct, there will be little additional cumulative fires until end of the fire season.
But – as said in the essay – the number is probably too low and not fully comparable to satellite datasets.
When comparing these numbers we have to remember that Giglio’s dataset is for calendar years, not for fire seasons.
I am seriously concerned.
As a child, One of my families properties in Healesville was burnt in 1981
I then experienced the 1983 Ash Wednesday bushfires in Victoria especially Cockatoo.
I observed how people came complacent over the following years until the 2009 Black Saturday bushfires. ( many friends lost their homes).
But my real concern is the peri urban area of Melbourne’s outer east. In excess of 100,000 people live amongst the trees and the three municipalities which cover these areas are some of the biggest opponents of fuel reduction.
There is to be a 6 month investigation in to this “fire season”. I bet you now there will be a report, there will be recommendations and they will all be ignored. Just like the 50 or more such investigations since the 1930’s. Nothing will be done and climate change will be blamed. If that is the case I suggest all fire fighters simply go home, especially, brave, international ones because there is nothing we can do to stop climate change.
Patrick
I am also pessimistic.
Nevertheless I hope there will be a commission.
I would then make a submission.
As the previous Royal Commission was so recent it will be easy to link the recommendations that have not been addressed to the actual government positions responsible.
For example recommendation 62
– did VicRoads assess the road into Mallacoota?
– did VicRoads plans to do works on the road?
– did they actually do the planned works?
My guess is no to the third question. There will actually be a person who is responsible for this.
After looking at the east Gippsland shire fire management plan it is clear the only road to access the tourist town of Mallacoota is the Genoa Mallacoota Road which should be cleared fence to fence.
Guess what not done ( based on street view).
There are still towns accessed by single roads. VicRoads should be held directly accountable for not clearing roads they have fully documented that need to be cleared.
I grew up in Darwin (Norther Territory) throughout primary school and early high school well before Cyclone Tracy blew it away and fire was a constant companion in the 6 month dry season. Darwin is surrounded by typical northern savannah woodland you can see here-
https://denr.nt.gov.au/__data/assets/pdf_file/0017/261062/vegetation-types-in-nt-factsheet.pdf
As you can imagine grasses and understory grow well in the 6 month wet season but come the dry those woodlands are burning regularly everywhere if not by lightning strike and the odd schoolkid or discarded bottle then by the high aboriginal population. They’re accompanied by the many hawks and kites wheeling overhead feasting on the fauna escaping the slow fire fronts.
But here’s the rub. They’re simply not a threat to property and human life as the fires don’t crown but continually burn the understory every dry season. Not hard to see that everywhere with the blackened trunks of the eucalypts in those woodlands. There is one difference with the SE eucalypt forests we’ve seen burn now. Savannah means flat but if you have steep valleys and gullies you’d best make sure the understory fuel load doesn’t build up to allow fire progressing up slopes to ignite the crown with all its eucalyptus oil or you’re in big trouble being anywhere near it. Mind you there’s lots of that undertaken now in the SE and it’s probably a good idea to maintain it like those savannah woodlands going forward although that’s a big task.
I’m impressed at how flammable sand is, in the center and North West of Australia.
Looking at the mean annual burn area. the burn rate is highest where the rainfall is also the highest.
Source Giglio et al 2013
Australia average annual rainfall:
http://www.bom.gov.au/jsp/ncc/climate_averages/rainfall/index.jsp
And the reason for the 2019-20 bushfires being mainly in east, was firstly the positive SAM conditions in winter giving NSW etc a proper soaking, followed by negative SAM in spring-summer giving dry conditions for the east, and exacerbated by the positive IOD index.
Understanding the Southern Annular Mode (SAM)
“SAM conditions in winter giving NSW etc a proper soaking”
NSW did not get a proper soaking in winter 2019 (or 2018 or 2019). It was in the grip of drought.
NSW winter rainfall
Thanks for the correction, autumn 2019 appears to be the last moderately wet period.
The overriding emphasis on agw as tge underlying cause and that the fires underscore the need for climate action get in the way of rational management
https://tambonthongchai.com/2020/02/02/tbgyozfire/
We had two very wet seasons about 6-7 years ago, then average to low rainfall. Lots of undergrowth and vegetation growth. Then the last two years were by far the driest two years in a row on record. Massively more dry than any previous pair of years. And then we had the dipole delaying the monsoon, and lots of very hot windy conditions. And less in the way of hazard reduction burns around properties. And more and more properties are being built ‘in the bush’ with large trees nearby.
Put an abundance of fuel near properties on 40+ days with 100kph winds and you get firestorms of rather massive dimensions.
I’m in my 60’s and have seen lots of bushfire seasons. There is no doubt at all that this was by far the worst, in scale and severity. No-one should attempt to under-estimate the magnitude of it. If you haven’t seen a video of how aggressive these fires are, seek them out. No amount of ‘fuel reduction’ would make any difference when a super aggressive fire happens. Fuel reduction burns, done frequently, are safer and easier to manage than if done intermittently, and can, if done around properties, make them easier to defend. But in really severe fire weather it’s tough to survive in the bush.
The monsoonal weather has finally arrived, very late, and we have rain. So it’s over, basically.
There’s no climate signal in it. It was the result of an unusual combination of events.
Chris.
With respect , estimated fire intensities on Black Saturday were twice anything observed this season….
It should be cause for consideration that it has taken us months to reach this extent, when some of the landmark seasons of the past reached their peaks in two or three days.
It has been a tough season, without doubt. But to claim it is unprecedented seems to require cherry-picking. We can always find exceptions if we do that hard enough.
Welcome to the land of drought and flooding rains-
https://www.msn.com/en-au/news/australia/a-months-worth-of-rain-in-a-week-wild-weather-to-drench-country/ar-BBZEwji
We’ll all be rooned said Hanrahan!
I don’t get how most climate research temperature forecast models include the positive feedback of increasing greenhouse effect due to increasing water vapour from more evaporation as temperatures rise, yet droughts and bushfires (i.e. less water vapour) are also considered a symptom of AGW. This seems to be a contradiction.
That’s old hat global warmening silly whereas there’s nothing climate change cannot do. You have to keep up or go to the back of the class with the rest of us still on climate disruption.
landclearing exacerbates drought and bushfires. record landclearing in oz over last 10 years.
indeed this is a problem, unlike CO2 emissions. landclearing and water mining are a big problem that is not being faced by either side of the discussion, cos it ends up pointing out the obvious: capitalism and long term survival are incompatible.
According to Australia’s government data, the forrested area has actually increased during last 20 years.
I guess this figure would include a lot of plantation eucalypts…but we have had record landclearing rates so in any case it is hard to see how forest regrowth – ie trees that take half a century or more to reach a maturity – could keep apace of the record rates of landclearing. a mature tree condenses more water on its leaves than it gets from rain – it is the maturity of forest that is important…mature trees provide multiple benefits in terms of biodiversity , water availability, wind protection, cooling effects from shade and transpiration, the seeding and increase of clouds through volatile compounds and eckmann spirals. a study in western australia found that landclearing was the primary cause of rainfall decline:
https://www.researchgate.net/publication/263071328_The_effect_of_land_clearing_on_rainfall_and_fresh_water_resources_in_Western_Australia_A_multi-functional_sustainability_analysis
https://www.abc.net.au/news/2013-11-21/evidence-land-clearing-leads-to-rainfall-reduction-found/5107392
i think it wise to stop the eucalyptus monocultures – they are just too flammable. reforesting with non-eucalyptus species – high value rainforest timbers for example, hoop pine, silky oak….mixed species planting, selectively harvested. the western australian researchers suggested reforesting with large native trees as primary long term strategy. in the short term i think hemp could also be treated as a forestry crop.
Your sensible comments regarding eucalypt monocultures echo those of biologist Jeremy Griffith in this recent article in The Spectator https://www.spectator.com.au/2020/01/the-science-of-bushfires-is-settled-part-2/
I’ve looked through several of the references but I can’t find where the bar chart: “Figure: Annual burned area in millions of hectares” for Australia is located.
Can anyone direct me to where Pasi Autio found it?
Thanks in advance.
You can find it from globafiredata.org. Select analysis tool. Select graph symbol from the left. Select what you want for your graph.
Very interesting thread. I thought it worth referencing this recent article by biologist Jeremy Griffith in which he addresses directly the ‘elephant in the room’ being the inherent fire danger of Eucalypts. Take a read https://www.spectator.com.au/2020/01/the-science-of-bushfires-is-settled-part-2/
Annual burned area in Australia
There are sources to place this bushfire season in the context like the study by Giglio at al 2013.
“Giglio” bears a curse.
https://www.google.com/search?client=ms-android-huawei&sxsrf=ACYBGNQRVLDJTf4hxVFqUOnGHs4WE8JoTA%3A1581788911063&ei=7y5IXsW4A7vQmwXpi6TIBw&q=captain+schettino+giglio&oq=captain+schettin+giglio&gs_l=mobile-gws-wiz-serp.