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One-third of our greenhouse gas emissions come from agriculture

One-third of our greenhouse gas emissions come from agriculture

Farmers advised to abandon vulnerable crops in face of climate change.

The global food system, from fertilizer manufacture to food storage and packaging, is responsible for up to one-third of all human-caused greenhouse-gas emissions, according to the latest figures from the Consultative Group on International Agricultural Research (CGIAR), a partnership of 15 research centres around the world.

In two reports published today1, 2, the CGIAR says that reducing agriculture’s carbon footprint is central to limiting climate change. And to help to ensure food security, farmers across the globe will probably have to switch to cultivating more climate-hardy crops and farming practices.

“The food-related emissions and the impacts of climate change on agriculture and the food system will profoundly alter the way we grow and produce food,” says Sonja Vermeulen, a plant scientist at the University of Copenhagen in Denmark and a co-author of one of the studies, which estimates the emissions footprint of food1.

Vermeulen and her colleagues examined for the first time the carbon emissions for all stages of the global food system. Previous work has only looked at the contribution of agricultural production to greenhouse-gas emissions, including the release of nitrous oxide from soils from farming techniques such as tilling.

Using estimates from 2005, 2007 and 2008, the researchers found that agricultural production provides the lion’s share of greenhouse-gas emissions from the food system, releasing up to 12,000 megatonnes of carbon dioxide equivalent a year — up to 86% of all food-related anthropogenic greenhouse-gas emissions. Next is fertilizer manufacture, which releases up to 575 megatonnes, followed by refrigeration, which emits 490 megatonnes. The researchers found that the whole food system released 9,800–16,900 megatonnes of carbon dioxide equivalent into the atmosphere in 2008, including indirect emissions from deforestation and land-use changes.