Confirming for the first time that human excrements contribute to water pollution, primarily with nitrogen and phosphorus, a study by the Universidad de Almería (UAL) says that every person emits the equivalent of approximately two tonnes of carbon dioxide a year from the time food is produced to when the human body excretes it, representing more than 20 per cent of total yearly emissions.

A team of researchers from UAL has estimated the environmental impact of the Spanish diet and role that human excrements play in the life cycle of food.

“Food in Spain produces emissions of around two tonnes of carbon dioxide per person and per year (more than 20 per cent of total emissions per person and per year) and consumes 20 gigajoules of primary energy,” main author of the study and researcher at the UAL Iván Muñoz said.

The study, which was published recently in The International Journal of Life Cycle Assessment, analyses the relationship of the food production and consumption chain with global warming and the acidification and eutrophication (excess of nutrients) of the environment, taking what a person in Spain ate in 2005 (881 kilograms) as a reference.

Calculations included agricultural and animal production, industrial food processing, sale and distribution, preparation and cooking at home, solid waste treatment, as well as human excretion, according to a press release from the Spanish Foundation for Science and Technology.

As regards emissions, human excreta have a net null effect on global warming, as they are offset by carbon fixation in photosynthesis.

As a consequence of this, they do not contribute to increasing the concentration of Carbon dioxide in the atmosphere.

Source: The Hindu, November 04, 2010.