A new study from researchers at the University of Sheffield has analysed the environmental impact of a loaf of bread.
With an estimated 12 million loaves sold in the U.K. daily, bread is an integral part of many Britons' diets.
The study, published in the journal Nature Plants, sought to analyse the whole process of a loaf's production, from growing and harvesting the wheat to milling the grain; producing the flour; baking the bread; and making the final product.
The study showed that the use of ammonium nitrate fertilizer in wheat cultivation contributed 43 percent of greenhouse gas emissions. This, the university said on Monday, dwarfed "all other processes in the supply chain."
"We found in every loaf there is embodied global warming resulting from the fertilizer applied to farmers' fields to increase their wheat harvest," Liam Goucher, the N8 Agrifood Research Fellow who carried out the study, said in a news release.
"This arises from the large amount of energy needed to make the fertilizer and from nitrous oxide gas released when it is degraded in the soil."
It is not just the production of a loaf of bread that has an impact.
In 2013, the Food and Agriculture Organization of the United Nations (FAO) said that total emissions from global livestock represented 14.5 percent of "all anthropogenic" greenhouse gas emissions. Cattle alone represented roughly 65 percent of emissions from the livestock sector, the FAO stated.
Back in Sheffield, the scale of the challenge relating to the production of staples was being taking seriously.
"Our findings bring into focus a key part of the food security challenge – resolving the major conflicts embedded in the agri-food system, whose primary purpose is to make money not to provide sustainable global food security," Peter Horton, chief research advisor to the Grantham Centre for Sustainable Futures at the University of Sheffield, said.
"High agricultural productivity – necessary for profit for farmers, agri-businesses and food retailers, whilst also keeping prices low for consumers – currently requires high levels of application of relatively cheap fertilisers," Horton, who was a corresponding author of the paper, added.
Horton went on to state that with more than 100 million tonnes of fertilizer being used every year to support agricultural production, a massive problem existed, with the environmental impact not costed within the system.
Solutions to possibly lessen the impact included better agronomic practices.
"These harness the best of organic farming combined with new technologies to better monitor the nutritional status of soils and plants and to recycle waste and with the promise of new wheat varieties able to utilize soil nitrogen more efficiently," Duncan Cameron, a co-author of the paper, said.