Gav,
as chance would have it there is a nice article in The Oz today about the Goyder Line.

Apparently the "beneficial warming" may have moved Goyders Line south, with the result that hundreds of more wheat farms are potentially unviable.

Goyders Line in South Australia marks the limit of "reliable rains" for wheat production. Goyder determed this ~150 years ago. Also some interesting history about opportunistic land grabs and pooh poohing of Goyders 'scientific' advice... needles to say, it ended in tears.

Maybe of interest for PeakEnergy.

Thanks SP - I hadn't noticed that one - very interesting (especially for those still pushing the grain ethanol wagon)...