"Land saved from cultivation offsets carbon emissions" Nature 465, 853 (2010)
This Nature News item reviews a paper published by Burney et al in PNAS entitled "Greenhouse gas mitigation by agricultural intensification." The article shows that agriculture today is more land-efficient than in 1960. Yet it has been interpreted to say that modern intensive industrial agriculture is better than organic. The authors should write a statement clarifying their work but they may not. The reason? The study, as written, is trivial, and only with the added implication is it interesting. But the implication is not true.
In addition to commiting the unforgivable sin of reasoning based on historical counterfactuals, the article presents a myopic and simplistic either-or argument rather than a systematic analysis of factors contributing to agricultural land use. The fact that 50% of all food produced is wasted strikes me as one area where adding efficiency could reduce the overall footprint of agriculture. Certainly the choice of which land to pave over (usually the most fertile agricultural land) and which land to convert to agriculture (eg primeval Amazonian rainforest) has been especially perverse and unnecessary. Furthermore, our society's choice of food is also not a given "quality of life" as the article assumes; rather, it is a socially constructed and contigent demand on land use. If Americans consumed more primary production (plants) and less secondary production (animals) we could vastly decrease our agricultural footprint.
Other issues could be raised, but these points show some of the many analytical failings of this article. Despite, or perhaps because of its unsupported thesis, it has also been extensively commented upon; the authoritative review of responses in here.