An anonymous reader writes Every year levels of carbon dioxide drop in the summer as plants "inhale," and climb again as they exhale after the growing season in the Northern Hemisphere. However, the last 50 years has seen the size of this swing has increase by as much as 50%, for reasons that aren't fully understood. A team of researchers may have the answer. They have shown that agricultural production, corn in particular, may generate up to 25% of the increase in this seasonal carbon cycle. "This study shows the power of modeling and data mining in addressing potential sources contributing to seasonal changes in carbon dioxide" program director for the National Science Foundation's Macro Systems Biology Program, who supported the research, Liz Blood says. "It points to the role of basic research in finding answers to complex problems."