Is Biodiesel Bad?

I read a recent article on the New Scientist Environment Blog entitled ‘One more nail in the biodiesel’s coffin’ and it depressed the hell out of me. I thought that perhaps biodiesel/biofuel would be in some part an answer to our oil dependency and pollution problems. Unfortunately a new study published by ‘Chemistry & Industry’ suggests that ‘diesel fuel made from rapeseed (canola) oil may produce even more greenhouse gas emissions than conventional diesel made from crude oil’. Apparently the problem is in growing the rapeseed oil because agricultural fields emit a lot of nitrous oxide gas which is 200-300 times as potent a greenhouse gas as carbon dioxide. It turns out that we would probably be better off using conventional fuel and planting lots of trees instead of growing rapeseed oil and burning biofuel. Is there any fuel that we can burn that doesn’t have a disastrous affect on the environment?