A recent article by a group of German researchers in Global Change Biology-Bioenergy(http://onlinelibrary.wiley.com/doi/10.1111/j.1757-1707.2010.01088.x/pdf)
looks at the future of biofuel crop expansion with respect to environmental concerns as well as agricultural constraints.
One of their main points is that, not surprisingly, devoting more of our ever-precious land for new (albeit promising) uses is not straightforward. There are already major land constraints globally (see figure above) where it is recognized that we should not devote further land for new uses. These reasons are colored in the figure above: the land is already protected, it is part of a sensitive wetland, it includes designated wilderness or has been identified as has having high biodiversity, carbon losses on conversion of the land would not be regained within a period of 10 years (LUC emissions), or these areas are already agricultural lands deemed necessary for food production.
While the authors estimate that bioenergy crops can account for a substantial amount (15-25%) of world energy demand by 2050, there are potential caveats, such as putting pressure on delicate ecosystems and fragmenting land. All of these issues are likely to have negative effects on biodiversity and threatened and endangered species.
My take-home message from reading this article:
It is imperative to be thinking long-term and focusing on renewable energy technology, yet we should definitely keep in mind the long-term and short-term sustainability of how biofuels affect our precious land.
