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A new study, published this week in Proceedings of the National Academy of Sciences, finds that agriculture has historically released almost as much carbon into the atmosphere as deforestation. The study says that land use changes associated with agriculture have caused the loss of 133 billion tons of carbon from soil worldwide over the last 12,000 years; at least half of those losses have occurred in the last few centuries. “Historically, I think we’ve underestimated the amount of emissions from soils due to land use change,” said lead study author Jonathan Sanderman, an associate scientist with the United States-based Woods Hole Research Center. The most intense losses per unit of land, the authors said, were caused by the planting of crops, although, because more land worldwide is devoted to grazing, the two activities are responsible for roughly equal amounts of global soil carbon losses. The researchers say it is virtually impossible to replace all 133 billion tons of lost carbon. “If we allow natural vegetation to take over the world, we may eventually get close to that,” Sanderman said. “But obviously we need to feed 7 billion people, going up to 10 billion by the middle of the century, so the reality is we are not going to be abandoning agricultural land and restoring it to its native state in any large way.” But, the authors suggest, their findings could be used to pinpoint parts of the world where losses have been highest in an effort to improve soil carbon storage. Land, added Sanderman, could also be managed in a more sustainable way, such as by using more efficient crop rotation strategies and modifying how land is plowed and tilled. “There’s a lot of studies showing that if you adopt recommended best management practices, you could slowly regain some fraction of that lost carbon,” Sanderman said.NEXT ARTICLE
A genetically modified organism (GMO) is an organism whose genetic material has been altered using genetic engineering techniques. Organisms that have been genetically modified include micro-organisms such as bacteria and yeast, insects, plants, fish, an...