Mongabay: Not long ago biofuels were seen as one of the major tools to combat climate change, but a large number of studies in recent years have shown that many first generation biofuels may have little climate benefitand some are actually harmfuland are also linked to rising food prices. Now, a new study in Nature Climate Change warns that biofuels using fast-growing trees (polar, willow, and eucalytpus) could also exacerbate ground-level ozone pollution. "Concerns about climate change and energy security...