I don't know if this is an appropriate subject for these forums; if it isn't I'm sure someone will let me know. It's just that I have become convinced that soil erosion -- not global climate change -- is the issue of the century. My tentative observations are the following: 1. The rate of soil erosion on arable land substantially exceeds the rate of soil formation. 2. There isn't much potentially arable land left that isn't highly erobable. 3. World poulation is now three times what it was when I was a boy and is still increasing. Much of the increase is urban, which takes away more arable land. 4. This set of factors -- if true -- is unsustainable, which -- being about food -- is deadly serious stuff. And I fear that technology won't help. The green rebvolution was about new crop varieties that depend on lots of irrigation and artificial fertilizer -- not sustainable. And GMOs have not been about yield, which is a very hard nut to crack, but with reducing farmers' pesticide and herbicide costs. Regards, Peter.