Your bad eating habits don't just harm you; they also hurt the planet. That's what a study from the Universidad de Almería (UAL) claims. According to researchers, individual food consumption is responsible for emitting approximately two tons of carbon dioxide each year from the time food is produced to when it is excreted. That's over 20% of the average person's yearly CO2 emissions in Spain, where the study was conducted.
The news shouldn't be all that surprising—animal production (including emissions from cow burps and farts), transportation, food packaging, and preparation are all familiar causes of greenhouse gas emissions. But human excrement? The study takes into account the CO2 produced by the human metabolism, as well as the emissions generated by toilet paper and toilet water.
Human excrement is responsible for more than just emissions. Iván Muñoz, the head author of the study, explained to ScienceDaily, "Human excretion contributes significantly to water polluting through providing organic matter and nutrients, such as nitrogen and phosphorus, which fosters the growth of algae, a decrease in the level of oxygen dissolved in the water, bad smells and other problems associated to eutrophication."
Returning wastewater back to the environment isn't a bad thing in theory, but many rivers have low water levels, making it difficult to soak up excrement, pesticides, fertilizers, and other pollutants.
There isn't much we can do about reducing the amount of excrement produced by our bodies, but we can cut down on carbon emissions—the UAL study shows that diets low in meat and dairy products have a lower overall environmental impact. We're still waiting to hear back from PETA, but we imagine that the carbon emissions argument is a powerful way to get consumers to change their dietary choices.