The potential for biofuels to play a sustainable role in meeting society’s energy needs in a climatically-neutral manner remains an open question even among ecologists, but little is known about public understanding of the scientific issues related to that feasibility. In order to comprehend debates about the topic, members of the public need to have some level of familiarity with global carbon cycling, especially the distinctions between carbon mineralization events as disparate as soil respiration, plant respiration and combustion of hydrocarbons. In addition, knowledge of the differences between a variety of agricultural practices and potential biofuel crop species, as well as their accompanying effects on land, water and biota in agricultural landscapes is necessary. Our study was designed to categorize and quantify patterns of reasoning in students (K-12) and adults (e.g. – teachers and college students) using a combination of clinical interviews and written assessments. Students and teachers were from representative rural/suburban school districts in areas potentially affected by biofuel cropping, and college students reflecting a range of majors and class levels were surveyed. Assessment instruments included diagnostic objective items, interpretation of standard diagrams used to represent the carbon cycle, and comprehension of educational materials (i.e.-pamphlets) on biofuels and their processing.

Results/Conclusions

Our results across a range of student ages show consistent difficulties in understanding many of these topics. In terms of biotic involvement in carbon cycling, for instance, over 95% of college students acknowledge that plants absorb CO₂ from the atmosphere during photosynthesis, but less than 5% identify plants and soil as respiring CO₂ as readily as animals. Assessments of college science students show a majority have difficulty describing connections between the biochemistry of feedstock processing and the structure of plants at the organismal level, as well as at the global scale of the carbon cycle. Half of students did not attribute soil respiration to the activity of microbes of soil organic carbon, and thus are in a poor position to understand the role of various agricultural practices (i.e.- tilling) in controlling carbon mineralization. In contrast, high percentages of secondary science teachers were able to clearly elucidate the technical hurdles to biofuel commercialization and the differences between grain-based and cellulosic ethanol. Together, these results suggest that although students are presented with and familiar with many relevant processes, they have difficulty understanding them when the setting is outside of the original learning context or when multiple scales need to be considered.