Saturday 2 August 2008

Refuting a still-believed myth once and for all

The few who have any idea about the radical climate changes occurring in Australia now, even if they realise global warming is looming as a terrible catastrophe, still seem stuck with a number of myths.

A longtime friend and associate of my mothers who is well aware of the declines in rainfall over southwestern Australia – and who is an expert in marine science – still said recently to me that the present increase in central-western Australian rainfall is a result of the region’s vegetation recovering from the damage done by gold mining in the 1890s. Although it is true that in the goldfields proper there were no rain gauges before gold was found – the gauge at at Coolgardie dates back to 1893 – the adjacent Eucla district where rainfall has increased equally greatly since the 1960s has gauges at Eucla dating back to 1876 and Eyre (further west on the coast) dating back to 1885.

Both the Eucla and the
less-complete Eyre rainfall data sets demonstrate that the clearing of vegetation, even if one does imagine it had major effects on so fragile an ecology, did not lower the region’s rainfall at all. The tables show no difference between the pre-clearing (black) and post-clearing (red) rainfall totals.

In fact, the driest years in the Eucla since 1885 were during the 1950s, the very decade most noted for abundant rainfall in currently-drying areas of southeastern Australia. At Eucla the driest year on records was 1957, with rainfall around four-fifths of the lowest recorded up to 1925. (The drought caused the worst dust-storms ever to hit Perth during November 1957). The former records broken at Eyre in 2000 and Eucla in 2006 were set precisely when the impact of land clearing should have been greatest and rainfall lowest.

Its time popular myths of land clearing driving declines in rainfall over arid Australia are demolished forever. The record rainfalls over the interior in the 1970s and arid WA since 1997 are entirely anthropogenic in causation and are in themselves enough reason to call for a radical wake-up to fight the car and coal companies.

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