Biofuels are commonly touted as a dual solution to the problems of dependence on foreign energy sources and climate change, but their impacts are not confined to these two areas. Energy production and use is one of the most intensive human enterprises, with numerous economic and societal benefits, as well as societal and environmental drawbacks. Any policy that seeks to significantly alter the form and method of energy exploitation raises the specter of unintended or misjudged consequences. The goal of greenhouse gas (GHG) savings was challenged after indirect land use change, resulting from displaced food and feed production, was included in the estimation of emissions.

...The capability of decision-makers to evaluate the total impacts of biofuels, including their environmental and economic trade-offs, and the accuracy of those evaluations depend on the availability of robust data and analyses. Here, we ask: does the published, peer-reviewed literature present a full portrait of biofuels and their potential impacts and trade-offs? Confidence in incipient policies governing biofuels that aspire to be environmentally, economically, and socially conscious, would be enhanced by an affirmative finding.

To answer the above question, we analyzed 1622 biofuels-related articles published between 2000 and 2009 across a range of social, environmental, and technical topics. We also examined geographic trends. Finally, we examined the frequency of interdisciplinary research as an index of our understanding of the complex interactions and feedbacks possible under global biofuel production scenarios. Such an approach has previously been used to visualize connections between concepts in the scientific literature and to identify logical gaps in study. We did not attempt to review the specific findings of the literature. Rather, our primary goal was to ascertain the structure of biofuels research efforts in the past decade in order to stimulate discussion of its utility to a range of stakeholders.

—Ridley et al.

They found a wide range of research activity. The number of peer-reviewed articles addressing the economic aspects of biofuels was approximately half that of either environment and human well-being or production-distribution technology and infrastructure articles. The most common topics in the literature were fuel production technologies, greenhouse gas (GHG) emissions, and feedstock production/agronomics, each with more than 300 articles.

The least studied topics, excluding geographical categories, were human health, trade, and biodiversity, which retrieved 129 articles combined. Human health and trade, in particular, were represented by a very limited number of articles (15 and 34, respectively).

Likewise, their analysis by region found substantial heterogeneity in total research effort and in topical emphasis. The network analysis also revealed strong asymmetry in the connectedness of different research topics in the biofuels literature.

Among 23 topics examined, GHG emissions was the most well-connected, sharing at least 50 articles with 11 other topics. Land use/land cover, feedstock production/agronomics, fuel production technology, and costs of production were also well-connected to other topics, including topics outside of their respective thematic areas. The topics with the fewest numbers of articles were also the most isolated.

Human health, trade, biodiversity, and feedstock logistics tended to be loosely associated or unassociated with articles in other disciplines. Noticeably scarce were studies on how economic policy, market factors, and trade might influence how biodiversity is impacted by biofuels. Although the lack of connections appeared to be a function of the small number of articles in the case of human health and trade, it was not exclusively so for biodiversity. Averaging the proportion of articles connected to each topic, biodiversity articles addressed another topic only 15% of the time versus, for example, 27% of the time for GHG articles.

—Ridley et al.

The lack of studies addressing human health, trade, and biodiversity has a number of implications, the authors noted, adding that large-scale production and use of biofuels is likely to modify several of the stressors that already threaten regional biodiversity, including land use change, climate change, air pollution, and biological invasions.

The underrepresentation of developing areas in the literature also raises questions about impacts of the industry in places where large-scale development of biofuels could either be extremely beneficial or lead to widespread environmental degradation, depending upon how development proceded.

Increasingly, organizations and governments are relying on systems approaches to understand the consequences of particular policy decisions. These are often interdisciplinary analyses to try and capture the complexities and feedbacks associated with increasing biofuel production, across the stages of the production chain, for multiple environmental and economic impact domains and from local to global scales. Common approaches include life cycle analyses (LCAs), and general and partial equilibrium models (e.g., Global Trade Analysis Project [GTAP] and others).

Although promising, these approaches are often hampered by the large amounts of input data required, as well as fundamental uncertainties in model processes such as market elasticities and local land management practices. We found that some topics such as GHG emissions and land use/land cover are commonly discussed in an interdisciplinary fashion. Whether this is in a substantive enough way to inform modeling efforts and/or policy decisions remains unanswered. On the other hand, many topics appeared relatively isolated, clouding the prospects for an integrated analysis on the impacts of biofuel production across multiple nations.

—Ridley et al.

Resources

• Caroline E. Ridley, Christopher M. Clark, Stephen D. LeDuc, Britta G. Bierwagen, Brenda B. Lin, Adrea Mehl, and David A. Tobias (2012) Biofuels: Network Analysis of the Literature Reveals Key Environmental and Economic Unknowns. Environmental Science & Technology doi: 10.1021/es2023253