Background
In the opening sentence of their abstract, the authors state that first-generation biofuels are an existing, scalable form of renewable energy of the type that is "urgently required to mitigate climate change," which is an important thing to remember about their mindset in light of the findings and implications of their work.

What was done
Bryan et al., as they describe it, "assessed the potential benefits, costs, and trade-offs associated with biofuels agriculture to inform bioenergy policy." More specifically, they indicate they "assessed different climate change and carbon subsidy scenarios in an 11.9 million hectare region in southern Australia," where they "modeled the spatial distribution of agricultural production, full life-cycle net greenhouse gas (GHG) emissions and net energy, and economic profitability for both food agriculture (wheat, legumes, sheep rotation) and biofuels agriculture (wheat, canola rotation for ethanol/biodiesel production)."

What was learned
The three Australian researchers report finding that "biofuels agriculture was more profitable over an extensive area of the most productive arable land," producing "large quantities of biofuels" that "substantially increased economic profit." But they add that the end result was "only a modest net GHG abatement" that had "a negligible effect on net energy production." In addition, they indicate that the economic profit was largely due to "farm subsidies for GHG mitigation," and that whatever benefits were accrued came "at the cost of substantially reduced food and fiber production."

What it means
When all is said and done, it is clear that it is only on the most productive arable land that biofuel agriculture turns a profit; and that profit comes not from normal economic considerations, but from farm subsidies paid by the government or the population at large. And the usurpation of the most productive arable land for biofuel production means there is an additional cost of reduced food and fiber production, which results in higher prices for these essential commodities, which prices are also paid by the population at large. And to add insult to injury, there is a negligible effect of biofuels on net energy production. Consequently, "if biofuels are to be embraced," as Bryan et al. comment in concluding their assessment of the issue, "additional policy design features and institutions are required to support farm subsidies." And for this fact to be admitted by scientists who feel that first-generation biofuels are urgently required says a lot about their brutal honesty in publishing their not-so-glowing findings about biofuel costs and effectiveness.