Saturday, January 23, 2010

Humans killing off Australia's animals and changing climate for 50,000 years

It is the accepted wisdom that primitive peoples lived in harmony with nature and that only modern man over-exploits the environment. This is bunkum, of course: ancient humans exploited natural resources without any regard for the environmental consequences whatsoever. Primitive peoples might well have had a close spiritual link to nature but they definitely did not make conscious decisions to conserve natural resources by limiting their harvests - if they needed food and game was available, they killed and ate it without considering the number of animals remaining. To think it otherwise is extremely naive.

It is therefore no surprise that researchers are amassing evidence that Australia's once abundant megafauna was killed off by humans. It's also no surprise that any evidence contradicting the notion of the noble savage is controversial - primitive peoples are just like us when it comes to exploitation, only less efficient. Those with an interest in preserving the myth of primitive cultures communing and living in harmony with nature will refuse to accept that the main concern was survival, not conservation.

But there is an alternative explanation for the disappearance of megafauna:

Disruption to the ecology of the Australian landscape caused by the burning practices of the continent’s first inhabitants probably led to the extinction of megafauna 50,000 years ago, according to new research.

The megafauna across Australia became extinct shortly after human arrival on the continent but at a time when climate records show there was no significant or consistent change across the continent. This suggests that humans played a role in the extinction but a specific human cause has never been pinpointed.

However, a research team including Dr John Magee and Dr Michael Gagan from ANU have suggested that an abrupt ecological change in food sources at 50,000 years ago was caused by burning practices of the continent’s first inhabitants.


In October 2004 and January 2005, the same joint research team published papers in the research journal Geology, suggesting that the same burning-induced ecosystem change 50,000 years ago triggered the failure of the annual Australian monsoon over the interior by altering the flora enough to decrease the exchange of water vapour between the biosphere and atmosphere.

Lake Eyre, formerly a deep-water lake in Australia's interior that was filled by regular monsoon rains about 60,000 years ago, is now a huge salt flat only occasionally covered by ephemeral floods, as in 1974.

If anything, modern humans take much better care of the environment than did our ancestors.



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