Biofuels: More Bang -- or Is it Baggage? -- for the Buck

In an article recently published in Ecological Applications, Bouwman et al. (2010) assessed the global consequences of implementing first- and second-generation bioenergy production in the coming five decades, focusing on the nitrogen cycle and utilizing "a climate mitigation scenario from the Organization for Economic Cooperation and Development's (OECD's) Environmental Outlook, in which a carbon tax is introduced to stimulate production of biofuels from energy crops." In doing so, they calculated that "the area of energy crops will increase from 8 Mha in the year 2000 to 270 Mha (14% of total cropland), producing 5.6 Pg dry matter per year (12% of energy use) in 2050." They also found that "this production requires an additional annual 19 Tg of N fertilizer in 2050 (15% of total), and this causes a global emission of 0.7 Tg of N₂O-N (8% of agricultural emissions), 0.2 Tg NO-N (6%), and 2.2 Tg of NH₃--N (5%)." In addition, they say that "2.6 Tg of NO₃--N will leach from fields under energy crops."

What might be some of the less-than-favorable impacts of these several consequences of carbon-tax-supported biofuel production?

For starters, the three Dutch researchers note that the greenhouse gas emissions that are supposed to be reduced by using biofuels instead of fossil fuels "are offset by 20% in 2030 and 15% in 2050 if N₂O emission from the cultivation of energy crops is accounted for." Yet even this blowback is but a fraction -- 30-60% for maize and sugar cane, according to Bouwman et al. -- "of total emissions from the cultivation, processing, and transportation of biofuels." In addition, they write that "on a regional scale, increased N leaching, groundwater pollution, eutrophication of aquatic and terrestrial ecosystems, N₂O and NH₃ emissions from energy crop production, and NO_X emissions from combustion of biofuels may cause relevant loss of human and ecosystem health." And with respect to the availability of land for the growing of biofuels, Bouwman et al. write that "the OECD-GC scenario shows a rapid expansion of agricultural land, mainly in Africa and the former Soviet Union," and they say that "this expansion will lead to a further loss of biodiversity."

Finally, on top of everything else, there is the question of economics: Is the use of biofuels really an economical approach to dealing with the perceived but unproven problem of CO₂-induced global warming? ... and why? The answer is provided by the three employees of the Netherlands Environmental Assessment Agency in the final paragraph of their paper, where they write that "bioenergy is economically feasible," but only "because of the climate change policies" that they say are "implemented through carbon taxes."