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Australian Bushfires Much Worse In 1974/5

January 9, 2020

By Paul Homewood


An important and, as usual,  forensic contribution from Roy Spencer:


Summary Points

1) Global wildfire activity has decreased in recent decades, making any localized increase (or decrease) in wildfire activity difficult to attribute to ‘global climate change’.

2) Like California, Australia is prone to bushfires every year during the dry season. Ample fuel and dry weather exists for devastating fires each year, even without excessive heat or drought, as illustrated by the record number of hectares burned (over 100 million) during 1974-75 when above-average precipitation and below-average temperatures existed.

3) Australian average temperatures in 2019 were well above what global warming theory can explain, illustrating the importance of natural year-to-year variability in weather patterns (e.g. drought and excessively high temperatures).

4) Australia precipitation was at a record low in 2019, but climate models predict no long-term trend in Australia precipitation, while the observed trend has been upward, not downward. This again highlights the importance of natural climate variability to fire weather conditions, as opposed to human-induced climate change.

5) While reductions in prescribed burning have probably contributed to the irregular increase in the number of years with large bush fires, a five-fold increase in population in the last 100 years has greatly increased potential ignition sources, both accidental and purposeful.

Historical Background

Australia has a long history of bush fires, with the Aborigines doing prescribed burns centuries (if not millennia) before European settlement. A good summary of the history of bushfires and their management was written by the CSIRO Division of Forestry twenty-five years ago, entitled Bushfires – An Integral Part of Australia’s Environment.

The current claim by many that human-caused climate change has made Australian bushfires worse is difficult to support, for a number of reasons. Bushfires (like wildfires elsewhere in the world) are a natural occurrence wherever there is strong seasonality in precipitation, with vegetation growing during the wet season and then becoming fuel for fire during the dry season.

All other factors being equal, wildfires (once ignited) will be made worse by higher temperatures, lower humidity, and stronger winds. But with the exception of dry lightning, the natural sources of fire ignition are pretty limited. High temperature and low humidity alone do not cause dead vegetation to spontaneously ignite.

As the human population increases, the potential ignition sources have increased rapidly. The population of Australia has increased five-fold in the last 100 years (from 5 million to 25 million). Discarded cigarettes and matches, vehicle catalytic converters, sparks from electrical equipment and transmission lines, campfires, prescribed burns going out of control, and arson are some of the more obvious source of human-caused ignition, and these can all be expected to increase with population.

Trends in Bushfire Activity

The following plot shows the major Australia bushfires over the same period of time (100 years) as the five-fold increase in the population of Australia. The data come from Wikipedia’s Bushfires in Australia.

Fig. 1. Yearly fire season (June through May) hectares burned by major bushfires in Australia since the 1919-20 season (2019-20 season total is as of January 7, 2020).

As can be seen, by far the largest area burned occurred during 1974-75, at over 100 million hectares (close to 15% of the total area of Australia). Curiously, though, according to Australia Bureau of Meteorology (BOM) data, the 1974-75 bushfires occurred during a year with above-average precipitation and below-average temperature. This is opposite to the narrative that major bushfires are a feature of just excessively hot and dry years.

Every dry season in Australia experiences excessive heat and low humidity.


 Full story here.

It has been widely reported that the recent fires in Australia are somehow “record”. Spencer’s graph shows this to be an outright lie.

As he notes, the fires of 1974/5 burnt some 100m hectares, compared to provisionally about 10m hectares this time. The fires in 2003 were also much worse.

And although it is attractive to link hot/dry weather to wildfires, as Spencer points out, 1974/5 was both wetter and cooler than average.

[BTW- the apparent uptick in fires since pre-war can very easily be explained. Back then most of the continent was relatively uninhabited, and fires were allowed to burn themselves out, without anybody bothering to measure them.]

This fire season has seen widespread fires across Australia, but records show that the fires in 1974/5 were just as widely spread.

For instance, Queensland alone saw 7.3m ha burn that summer, while in NSW 4.5m ha was lost.

Elsewhere 16m and 29m ha was lost to fire in South and Western Australia respectively:






News media readily jumps on climate change as the main cause of Australia’s bushfires, because people assume that hot, dry weather leads to fires. The facts show that things are much more complicated.

Certainly the massive increase in population must also play a major part. With any wildfire, a source of ignition is needed. In nature, lightning can be a cause, but this is extremely unlikely in such dry weather conditions.

But we do know that humans are responsible for probably the vast majority of fires in one way or another, whether deliberate arson, or unintentionally via vehicles, power lines, campfires, discarded matches and cigarettes, etc.

As Roy Spencer concludes:

So, to automatically blame the Australian bushfires on human-caused climate change is mostly alarmist nonsense, with virtually no basis in fact.

  1. January 9, 2020 10:25 pm

    Reblogged this on Climate Collections.

    • Joe Public permalink
      January 9, 2020 11:18 pm

      Paul correctly claimed “Green ideology, not climate change, makes bushfires worse”

      I see that that Climate Feedback article states the (different) claims by others that: “the bushfires [in Australia] were caused by arsonists and a series of lightning strikes, not ‘climate change'” as ‘Misleading’

      It’s ironic that their ‘Expert’ Stefan Doerr, Professor, Swansea University states:

      “The combination of such widespread temperature maxima not recorded before combined with very dry live and dead vegetation following a long and severe drought has allowed the ignitions (be it arson, lightning, or accidental) to conflagrate to fires covering an unprecedented geographic range in recorded history.”

      He’s obviously oblivious to the 101,800,000ha burnt in the 1974-75 season.

    • A C Osborn permalink
      January 10, 2020 9:38 am

      That article is completely fact free and worthless.

    • January 10, 2020 10:20 am

      Will do!

  2. Joe Public permalink
    January 9, 2020 10:55 pm

    WikiP has a page devoted to the tragedy.–20_Australian_bushfire_season

    “2019–20 Australian bushfire season”

    The 2019–20 bushfire season is of notable intensity compared to previous seasons as it has burned an estimated 10.7 million hectares (26 million acres; 107,000 square kilometres; 41,000 square miles), destroyed over 5,900 buildings (including over 2,204 homes) and killed 28 people as of 8 January 2020.

  3. Mack permalink
    January 9, 2020 11:24 pm

    The 2019-20 bushfire season has, indeed, been notable thus far. But not in the least bit unprecedented or, indeed, unusual. It’s primarily been noteable for the morons who claim that this year’s fires are an example of runaway man nade global warming writ large, as opposed to the usual cycle of drought, high temps, even higher fuel loads, crap land management and human ignition devices.

  4. January 10, 2020 12:03 am

    Reblogged this on ajmarciniak.

  5. Adrian, East Anglia permalink
    January 10, 2020 12:37 am

    Once again it is becomes clear that hysterical claims of a “record” event turn out to be both wildly inaccurate and factually unfounded. Alongside the existence of detailed records, what I find most striking is that apparently worse fires have occurred well within living memory. Even if the media are unable to conduct the most basic of checks, surely they would be talking to local people. On the other hand, maybe not!!

  6. Broadlands permalink
    January 10, 2020 12:59 am

    “But we do know that humans are responsible for probably the vast majority of fires in one way or another, whether deliberate arson, or unintentionally via vehicles, power lines, campfires, discarded matches and cigarettes, etc.”

    It might be worth adding that in 1974-75 the amount of CO2 in the atmosphere at Mauna Loa was only 330 ppm while the global population was at least three billion fewer than now.

    So today, is it “global warming” from our added CO2, or just a lot more people… Both or neither? Natural seasonal variability seems more likely to be the proximate cause.

  7. Peter Crump permalink
    January 10, 2020 7:27 am

    Realistic approach.

  8. January 10, 2020 9:10 am

    Reblogged this on Tallbloke's Talkshop and commented:
    Note to climate doomers: weather can vary without assistance from humans.

  9. Gerry, England permalink
    January 10, 2020 1:52 pm

    Jo Nova has a piece about what happened in 1939. Two very interesting last sentences:

    ‘There is some reassurance there knowing that government was just as inept, corrupt and incompetent then. Though we have less excuse…’

  10. Arthur Krugler permalink
    January 10, 2020 7:54 pm

    Temperature – “So today, is it “global warming” from our added CO2, or just a lot more people… Both or neither? Natural seasonal variability seems more likely to be the proximate cause.”
    Actually neither, the answer is beneath the surface and the trees and brush.
    Australia has an enormous amount of uranium underground; more than any other country.
    Australia has 24 % of the total known global deposits; Next is Kazakstan with 12%.
    Why is that important? Because sunspots tigger the uranium to start the fission reactions and generate a lot of heat. Those countries that have uranium deposits are countries where temperature has increased – Those without have not shown any increase in temperature.

    I have written an article and emailed it to over 250 people. No it is not CO2 or hydrocarbons or coal or population. It is too long to attach here.

  11. Joe R permalink
    January 12, 2020 11:32 pm

    Newsweek confirms the 70s fire here

  12. Gary permalink
    January 19, 2020 12:27 pm

    Yep funny how people assume what they are being fed as correct and ignore real facts
    If u look at it there are sea shells in rocks in the middle of Australia apparently it used to be an ocean ? So the world has been getting drier for over a million years !!!!
    And I don’t remember the the flintsones even burning fossil fuels

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