Could bio fuels contribute to Global Warming?

A study in England has questioned the use a sustainability of bio fuels. By taking farm land out of production of food grains, has caused an increase in food prices globally. It appears that in our effort to reduce need for oil and reduce greenhouse gases we have created many new problems. They are also other reports that say the shift in crop production is not the cause for the food price increases. That the land and crops are not being redirected. This is a global problem. We should encourage all countries leadership to get this one right. This will effect our grandchildren severely. The article at the listed web site has some interesting questions. Read it and let me know what you think.