Spain’s Universidad de Almería study points out that every individual releases the corresponding amount of roughly two tons of carbon dioxide in a year. This number aggregates the carbon dioxide generated from the time of food production to the time when the same is excreted by the human body.

The aggregated number accounts for over 20% of the total yearly emissions. This study confirms that human fecal matter also contributes to water pollution, chiefly with phosphorus and nitrogen.

The team led by Iván Muñoz has projected for the first time the environmental impact of the Spanish diet and more so the role of human fecal matter in the life cycle of food.

"Food in Spain produces emissions of around two tons of carbon dioxide per person and per year (more than 20% of total emissions per person and per year) and consumes 20 gigajoules of primary energy," Iván Muñoz researcher at the UAL said.

The study, seeks to analyze the link between consumption and production of food to global warming and the eutrophication (excess of nutrients) and acidification of environment. The base line for this assessment was the 2005 reference of what a person in Spain ate in-881 kilograms.