November 29, 2006 | Graham

Droughts – the 40,000 year story

I’ve been following the story of the extinction of Australia’s megafauna for some time. It originally seemed reasonable to blame man as the extinction occurred at about the same time as we arrived in Australia – about BC 40,000. This fitted the pattern of other extinctions in other parts of the world where the arrival of the highest order predator in the history of the world led to various beasts dying out.
The most recent research, reported by the Herald Sun in this article suggests that it was climate change that did it, not the mighty hunter. This research has an AGW application. If you check out the East Antarctica temperature chart I published in an earlier post here you’ll see that 40,000 years ago it was very much colder than it is now (40,000 years ago coincides with the second trough from the right).
Somewhere around this time, without any help from manmade CO2 emissions, there were significant temperature fluctuations of around 2.5 to 3.5 degrees. We probably don’t know how much these contributed to the change in rainfall, but what it does demonstrate is that climate change is a constant, even in the absence of man. And it underscores the fact that this is a world where climate can and does change.
In the face of this our response to increasing CO2 levels is to wring our hands and talk about taming CO2 as a way of “combatting climate change”, when the correct response ought to be to ensure that, unlike the mega-fauna, we are in a position to adapt to it. We also invent excuses for our inaction, such as – “This is the worst drought in 100/1,000 years”. You can’t absolutely fight climate change, but as evolution shows, you can learn to live with it. But that sometimes means taking tough decisions.

Posted by Graham at 12:34 pm | Comments (11) |
Filed under: Australian Politics


  1. Well yes, the climate can change, and lo and behold we have known for a long time that is the case, and that carbon dioxide seems to be one the main factors, along with others like intensity of sunlight, volcanic eruptions etc.
    However, 40 000 years ago there was also not a global industrial culture of 6 billion humans that has already exploited the readily available natural resources before any change in the climate.
    The integrity and natural resilience of our life support systems (that’s the biodiversity of plants and animals, rain, clean air and water) have already been significantly degraded.
    What might’ve proven extremely hard going 40 000 yrs ago, will likely be even more destructive now.
    The current baseline levels of water in the environment are no doubt already below what they were prior to any mega-drought 40 000 yrs ago.
    So where does that leave us?
    The complex ecosystems that developed over millions and millions of year collectively buffer and protect many of their constituent members (including us) from too many vagaries of climate.
    We have cut swathes through these in a few hundred years.
    More to the point, when things do get tough, it is mostly likely the creatures with the highest needs/demands on natural resources that will go first… and that’s us currently.
    Humble creatures, insects, bacteria etc are the most likely to gain from rapid warming.
    Luckily, all humans still have the enzyme in their digestive system for breaking down insect exo-skeletons, a testament to the fact that human survival has involved utilising resources such as insects in the past.
    In this weird age of irony, it is only fitting that so many Australians for instance have rattled off the fact that we’re the driest continent on earth like a badge of honour, and laugh at how we’re the biggest users of water in the world as well.
    Funny or stupid? Both?

    Comment by anybody — December 1, 2006 @ 3:36 pm

  2. Anybody, you said “The current baseline levels of water in the environment are no doubt already below what they were prior to any mega-drought 40 000 yrs ago.” In fact, the reverse is likely to be true. It appears to have been colder 40,000 years ago with sea levels lower than they are now. By “baseline” I assume you mean “available”.

    Comment by Graham Young — December 3, 2006 @ 12:40 pm

  3. It is specualtive whether actual ‘available’ surface and subsurface water supplies were higher or lower then.
    Based on
    Studies suggesting that Australia has been getting progressively drier over the last 2 million years.
    Large contiguous areas of temperate, sub-tropical and tropical old growth rainforest having been removed over the last two hundred years. That undoubtably acted as refugia during times of water stress and they didn’t just appear in the last 40 000 years.
    The widely noted reduction in large water sources such as the now not so great artesian basin, after thousands of bores were placed around the place. This water is I believe deposited over millions of years and would not have been squandered during a drought 40 000 yrs ago.
    Large wetland areas that were drained for use as agricultural lands.
    I would definitely say that if you consider the water available for the maintenance of the Australian environment (our life support system) it would be lower now than 40 000 years ago.
    If you were to include every drop of water we extract from the environment to maintain our modern industrial society then it might be more as an actual volume.
    Whilst it would be interesting to have some figures to argue over, it would also be worth considering not only how much, but whether any particular use is adding or detracting from our environment in the long run.
    Either way, I definitely think that most larger intact ecosystems were in the past important for buffering against background climate variation, and available water.

    Comment by anybody — December 3, 2006 @ 5:04 pm

  4. Anybody, I think you’re making this up. What are the studies that you refer to that purport to measure water 2 million years ago?
    And how did the Great Artesian Basin get into your analysis? It’s not water that would have been available to the mega-fauna 40,000 years ago.
    Which wetlands that have been drained are you referring to?
    You strike me as someone who’s made up their mind and who is not susceptible to science. But I’m happy to be proved wrong on this.

    Comment by Graham Young — December 4, 2006 @ 11:21 pm

  5. Happy to be proved wrong?
    Seems strange that you’d be feel “happy” to be shown that ignorance such as your has contributed to destruction of the environment for future generations, effectively, for ever.
    Still our sorry fat arses will be long gone then so who cares.
    Australia is the most infertile continent on the planet. The reasons are spelt out in Mary E White’s book “After the Greening – the browning of Australia” and her latest, “Listen – our land is crying”.
    Intelligent capable people have considered these topics you apparently can’t believe are true.
    Once you’ve gone and done some of the most basic research on the climate/ecological history of Australia, you might even have something useful to contribute.
    Your country is burning and dying and really if you think it’s all about pompous argument… for anyone with eyes and a brain, there is ample evidence that modern Australia has collectively made a mess of this place, and continues to.
    See the latest State of the Environment Report (6 Dec 2006).

    Comment by somebody — December 10, 2006 @ 7:42 am

  6. Seeing as there appears to be some ignorance about good sources of information about water and ‘drought’ in Australia around here.
    I’ve offered the following information.
    In future, ignorance will be no good as an excuse.
    As I said, after you’ve done some basic research, you may be able to come back with something useful to say.
    From a bio of Mary E White
    “An account of how Australia became the driest vegetated continent, After the Greening, The Browning of Australia was published by Kangaroo press in 1994 and won the Eureka Prize. Listen … Our Land is Crying, on the Australian environment, its problems and solutions, followed in September 1997. Its companion volume Running Down – Water in a Changing Land — was launched on the 23rd of October 2000 by Dr Graham Harris, Chief of CSIRO Land and Water. It covers palaeodrainages; ancient river systems; what our rivers were like at the time of European settlement, and how they are today, groundwater and all aspects of Australia’s most precious resource. Listen and Running Down explain how the geological history of the continent pre-determined many of the problems that European-style land and water use have caused.
    The Greening of Gondwana, After the Greening, Listen and Running Down form a four part saga, a background to understanding why much of our current land and water use is unsustainable.”
    “The Queensland University of Technology granted her the degree of Doctor of the University on the 20th September 1999. She received the Riversleigh medal ‘for excellence in promoting understanding of Australian prehistory’ in December 1999.”

    Comment by nobody — December 10, 2006 @ 7:52 am

  7. Anybody/Nobody/Somebody, one of the distinguishing factors about the biota of the Internet is that there is always some opinionated anonymous person who can use Google to produce out-of-context quotes to “prove” their case.
    I’m not arguing about whether Australia has got drier over the last 2 million years but about the last 40,000, and whether mankind has had anything much to do with any dryness.
    40,000 years ago we were in a glacial era, and there is less free water in glacial eras. It’s a function of physics – lower temperatures mean less evaporation and therefore less precipitation.
    For what it’s worth, the 2006 State of the Environment Report, which you cite says “Australia’s climate has always been extremely variable. In the last 200 years we have not seen the full range of extremes.” I.e. it can get drier and wetter, hotter and colder, than it is at the moment.
    They also have a very interesting graph for temperature changes over Australia since 1910 – they appear to be less on average than the 0.6 degree increase generally touted as the increase in world temperature. You can access the summary documents for the report from

    Comment by Graham Young — December 10, 2006 @ 1:41 pm

  8. You said this was about ANTARTICA.
    It’s mainly about AUSTRALIA

    Comment by kotiy — December 11, 2006 @ 1:57 am

  9. First: make biodiesel from CO2
    Second: feed biodiesel into water making machine
    Third: Stop using artificial fertilizers
    Fourth: Plant salt tolerating groundcover
    Fifth: Roll up your sleeves and stop bs’ing about 40.000yrs ago.Our DNA will change with the times.(See the aboriginals) We only live shorter.
    Sixth: Start organic farming.

    Comment by Will H — December 11, 2006 @ 1:49 pm

  10. Will H, the biodiesel idea looks interesting, except I can’t help wondering whether it wouldn’t be more profitable to just set-up ponds to grow the algae. The devices they are using sound complex and expensive.

    Comment by Graham Young — December 11, 2006 @ 10:44 pm

  11. Will H, the biodiesel idea looks interesting, except I can’t help wondering whether it wouldn’t be more profitable to just set-up ponds to grow the algae. The devices they are using sound complex and expensive.

    Comment by Graham Young — December 11, 2006 @ 10:45 pm

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