At 09:09 PM 12/27/2011, you wrote: >I am unclear what >triggerd the climate changes in north Africa, causing the Sahara Dessert >Where I believe 2000 years ago there were grain fields? I have read that pastoralism (overgrazing) is one major factor in desertification. We in the developed world can do little to resist this. I've sent several requests to an organization called the Heifer Project to take me off their mailing list, because there is no way I'm paying them to give out goats or cattle. (Chickens, OK.) Another thing to think about, especially around the Christmas gift season, is what the production of cashmere is doing in Mongolia: it comes from goats, and they are being raised on marginal arid lands. However appealing it is and however inexpensive it has become, let's boycott it. Overgrazing has led to the destruction or impending demise of many plant species, to wholesale changes in ecological communities, and to the periodic suffering of pastoral societies through famine and territorial warfare. It is highly unlikely that the human species as a whole will become vegan, so reducing and eventually reversing its expansion through education and the empowerment of women is perhaps its best hope. Jane McGary Portland, Oregon, USA