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Quite interesting as relatives used to live on Eyre Pensinsula and they would point out 'that's Goyder's Line next to that stump'. The concept of it moving was never envisaged. As farming got harder at least some locals got jobs at Roxby Downs without feeling isolated like city slickers.
For smartarses the technical term I believe is 200 millimetre isohyet. However now I think we need a 3D concept, not just rainfall contours but another dimension for rainfall variability. It may be that some annual contours (isohyets) are constant but the seasonal standard deviation is changing ie long dry spells punctuated by irregular storms. Net of evaporation the contours would change however.
The other factor governing where the line is for farming is wheat yield - the article talks about some genetically engineered varieties which do better in low rainfall environments - but this is more of a aid to retreating slowly than a fix to the problem...
On rereading the article I see they reckon more like 250mm; those Eyreheads (residents of Eyre Peninsula) told me wrong.
I think rainfall variability is a ticking time bomb. For example the 'sustainable harvest' of logs for Gunn's new pulp mill may be far less than claimed. Ditto river red gums along the Murray-Darling. We might think a tree or an annual cereal crop can take a dry spell but then they go and die on us. Alternative hardy plants may survive but they don't waste effort on high yields of oil (fatty oil, not essential oil) and plump seeds. This year could be an eye opener.
Yes - I suspect big changes are coming down the pipeline as it runs out of water.
(Well - I'm assuming southern Australia really is drying out - here on the east coast it is *really* wet)
Bill Heffernan noted in the article that agriculture is going to have to follow the water - and that means heading north (one of his occasional moments of sanity).
Maybe the great Ord River project and other similar ventures will be revived...