Thursday, 21 May 2009

Global warming or hardiness?

In this article I discovered today, there is a description of cane toads moving into the (formerly) arid western part of Queensland. The author, a Sydney University professor called Rick Shine, says that toads are constantly spreading into the desert and that he is surprised by this.

However, the question is whether it is man-made global warming that is allowing the toads to spread rather then their own gradual movement. Shine does not say whether their spread is via river flow of their eggs or by them moving, but the fact that the spread has been noticed for the first time amidst record rainfall in the Lake Eyre catchment does sound a grave warning anthropogenic global warming is involved in a manner as deadly as the recent fires in Victoria.

Although the flood on the Georgina is only the fourth highest on record, I am by no means sure that even one of the three higher floods occurred before 1967 when man-made global warming was not an influence. I know the rainfall data well enough to realise that only in 1949/1950 and perhaps 1894/1895 is there likely to have been a flood as high as that this year. Moreover, rainfall data further downstream seem to suggest extremely dry years that were common before 1967 no longer occur. Such dry years would have been in the past an effective control on toads' spreading since nowhere in their native range must they adapt to this level of dryness.

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