In case your view of biofuels had not yet shifted to something more nuanced than they being a universally great alternative to petroleum products, a new study from Switzerland's Federal Laboratories for Materials Science and Technology (Empa) summed up in the graphic below, should definitely change your mind.
As you can see, although many biofuels do result in lower greenhouse gas emissions than either gasoline or diesel fuel as mixed in Switzerland (palm oil in Malaysia being a notable exception, as many studies have documented), and they all result in significantly lower ozone depletion, on every other factor looked at in the study biofuels are at best no better than petroleum and in many cases having greater than 167% worse environmental impact on multiple serious criteria such as creation of ocean dead zones, water pollution, land use change, and resource depletion.
Summing up the findings, via Science Daily:
Biofuels from deforested areas usually emit more greenhouse gases than fossil fuels. This also applies to indirect land usage changes if existing agricultural land is used for the first time for biofuel production and, as a consequence, forested areas have to be cleared in order to maintain the existing foodstuff or animal feed production.
On the other hand, positive effects can be achieved if energy plant cultivation increases the carbon content of the soil, for example via the cultivation of oil palms on unused grazing land in Columbia or via jatropha plantations in India and eastern Africa, making deserted land arable again. "Despite this, you can't speak in general terms of Jatropha as being a 'wonder plant', as its ecobalance is very much dependent on the agricultural practices at the site in question and the land's previous use," says Zah. Each (new) biofuel must therefore be examined separately and in detail.