Ray, were it that normal in the past, no vegetation-dependent wildlife would have survived because left unchecked by man, the fires would have spread everywhere there was vegetation to burn. Maybe some ants, snakes, lizards and other hole-entering creatures could have survived, but even then, you can cook by placing a chicken in a hole and lighting a fire above it. Your nationally symbolic creatures would have sizzled in their holes, barbecued on branches and charred in the meadows.
Sure, settlers probably brought their own dogs now and again, but that would have been much later in history. Camels yes, but I'm sure they didn't think to ship in spare kangaroos and koalas from somewhere, let along eucalyptus trees.
Rob,
The most current records we have, show that drought and bush fires are a normal feature of the Australian climate. The Aboriginals used fire for many thousands of years to control the environment. The fires were used as a tool that encouraged the growth and extent of grasslands to enhance the hunting of kangaroos, and so on, reduce levels of fuel on the forest floor, and keep vegetation from becoming dense and hard to walk through.
Recent Antarctic ice cores reveal that there have been far worse mega droughts in the past, in Australia, than anything experienced since the British colonized the country. The famous Eucalyptus tree which sheds its bark seasonally, instead of its leaves as most trees do, contributes to the frequent bush fires because it provides so much fuel, including oils, that easily burn. However, the trees have adapted to survive bush fires better than most other trees. They regrow from the ashes. From Wikipedia:
"Eucalyptus oil is highly flammable; ignited trees have been known to explode. Bushfires can travel easily through the oil-rich air of the tree crowns. Eucalypts obtain long-term fire survivability from their ability to regenerate from epicormic buds situated deep within their thick bark, or from lignotubers, or by producing serotinous fruits."The previous drought in Australia, known as the Millennium drought, from 2001 to 2009, was described as the worst on record. When the drought broke in 2010-11, the rainfall was so significant, and the natural inland lakes, such as lake Eyre, were so dry, that the amount of accumulated water prevented from flowing back to sea, stopped global sea level rise for 18 months. Global sea levels even fell slightly, initially.
An 8-year drought sounds awful, but how awful would a 39-year drought be? The ice-core records show this occurred in Australia during the Medieval Warm Period.
https://www.researchgate.net/publication/291167238_A_new_direction_for_Antarctic_ice_cores_reconstructing_Pacific_decadal_variability_and_Australian_drought_history_from_the_Law_Dome_ice_core"Eight ‘mega-droughts’ (dry periods >5 years duration) were identified over the last millennium. Six mega-droughts occurred between AD 1000-1320 including one 39 y drought (AD 1174–1212). Water resources and infrastructure planning in Australia has been based on very limited statistical certainty around drought risk due to the short ( 100 year) instrumental record and lack of rainfall proxies. This study shows that, similar to SW North America, Australia also experienced mega-droughts during the medieval period. Knowledge of the occurrence, duration and frequency of such mega-droughts will greatly improve drought risk assessment in Australia."http://www.antarctica.gov.au/news/2014/antarctic-ice-cores-tell-1000-year-australian-drought-story“The study shows that the Millennium Drought was far from an exceptional event for eastern Australia during the past thousand years.”
“Droughts lasting longer than five years are in fact a normal part of long-term climate variability, and should therefore be factored into catchment management.”
The Interdecadal Pacific Oscillation (IPO) describes a roughly 25-year cycle in the sea surface temperature, wind and other factors in the Pacific Ocean.
The IPO’s positive phase is closely linked with longer and more severe droughts in the United States and Australia. The risk of droughts occurring in Australia is higher during the IPO’s positive phase.Hope I've managed to elucidate this issue for you.
