It can be hard to come to grips with exactly what a changing climate in Australia, and the World, is going to mean for our children and grandchildren. Oh we get detailed maps and graphs from CSIRO and the BOM. People head north to see if we can swap agriculture in the south for agriculture in the north (we can’t). Record-breaking hot days and droughts and bushfires and bleaching coral and species movements all give us tastes of what is coming, what rough beasts are lurching towards us. Four horsemen of the apocalypse and all that.

So it is a pity that there weren’t changes in the past that could give us a better picture of what we are in for. Um, just a minute. Oh yes, sorry, where was I?

Past climate changes in Australia give us a frightening glimpse of what rising temperatures are going to mean. The fluctuations in the Pleistocene period alone lead to the extinction of many species, with the last of what are called megafauna (rough beasts all) disappearing forever with the last climate shift some 30-50000 years ago. We know that when lakes dry up, and sand dunes blow, and the arid interior extends out towards coastal regions, many species were unable to adapt. It’s going to happen again, but worse because the change this time is coming so rapidly (not something that the past has prepared us for).

You may have heard something about this before. The megafauna of Australia have been known since the early nineteenth century (as early as Thomas Mitchell’s expedition in fact), and today every schoolchild at least knows the name Diprotodon (which is not to say that they, and taxi drivers in my experience, don’t confuse Diprotodons and Dinosaurs, another group pushed to extinction by climate change, not humans, although creationists may disagree). But you may have thought that their extinction was caused by humans, and to see why we need to back pedal a bit.

In the nineteenth century debate was pretty even between those who thought humans done it, and those who thought it was the swings and arrows of outrageous climate shifts. There was, even in such an apparently esoteric debate, an ideological component. From the time Darwin first published on evolution in 1859, Australian extinctions were seen as something of a test case. For the anti-evolutionists, humans must have killed, over-killed in fact, the megafauna, because to accept that climate change was the culprit would have been to support Darwin’s mechanism of natural selection.

In the twentieth century debate continued, but, with acceptance of the truth of evolution almost universal apart from a few misguided people with a religious ideology to protect, the battle was fought over different philosophical grounds. Now some well-meaning academics set out to show that Aborigines were not “intelligent parasites” as one academic had termed them, but had played an active role in modifying and moulding the Australian environment. The twin prongs of this activity were, supposedly, the use of fire, and the hunting which was said to have caused the extinction of the megafauna. On the other hand a number of opponents have argued that fire didn’t play a role in modifying the Australian environment, and that the overkill suggestion made no sense at all in the real world.

There are a range of vested interests with bets on the outcome of this debate. Some are on the side of the angels, arguing for the proposition that Aboriginal people do have a right to the country because they did modify the environment massively. Others are less angelic, arguing that if Aborigines (no better than the rest of us then) modified the environment massively so could or should we. Others want to argue against any notion of Aborigines as conservationists, acting in the interest of the society, because they want to promote the idea that greed is good, and that the natural state of humanity is all for one and all for one. Good government is no government, and we should only conserve things, by private ownership or commercial development, that are of value to humans, put on earth to hold dominion over the birds of the air and the beasts of the field. Furthermore if climate change caused such massive extinctions then we really should get our act together on greenhouse gases pretty quickly or there will be tears before bedtime and that is not a message that big business and its allies wants promoted.

This debate sputtered along over the last 50 years or so. Gradually the general public came to believe that humans did it (and had used fire extensively) because this was a view that apparently matched the ideology of the media proprietors, and, in addition, it made for a good story. Dramatic. Vivid. Action-packed. Humans red in tooth and spear. Flames leaping in the night. The trend had nothing to do with evidence, in fact what evidence there was all pointed in the opposite direction. But there were a few sites which provided straws in the wind. Sites that suggested that the last of the megafauna had survived long after human arrival, and a lack of sites that suggested any massacres of megafauna of the kind that the overkill theory relied on.

If you were that way inclined, were a climate change causation denier, then you could find fault with every site put forward, just as modern climate change deniers reject every piece of evidence without seeing an overall picture. The best site, discussed recently on Catalyst, is Cuddies Springs, excavated by Judith Field. It is a site that demonstrates conclusively a long association between humans and megafauna, and a survival of megafauna long after the arrival of humans on the Australian continent. Game set and match.

Oh the ideology continues to inform argument, just as in the case of Global Warming. But we are now able to turn our attention to the reality that climate change has in the past, and will in the future, cause many extinctions of animal species in Australia (and elsewhere), and those extinctions mean radical changes in the ecosystems that sustain all life on this harsh continent.

When I began working on the prehistory of Australia over 35 years ago it was because it was a fascinating research topic full of unanswered questions and challenging analytical problems. It was the subject of many academic papers and impassioned debates in lecture rooms and conference venues. I was perhaps, a little embarrassed to be paid for doing what was so much fun but which was of such esoteric interest that I don’t remember meeting anyone in the non-academic world that knew, or cared, about the difference between Diprotodons and Dinosaurs. Turns out that a knowledge of Australia’s past is a vital component as we battle for Australia’s future.