Carnegie Mellon University researchers found greenhouse gas emissions from lettuce production is over three times worse compared to bacon production. Two whole iceberg lettuces contain the same calorie intake as two slices of bacon. Low-calorie foods with faster expiration dates result in higher gas emission footprints from several aspects of the food supply chain.
A comparative analysis of gas emissions resulting from 1,000-calorie food production found lettuce can be worse for the environment compared to bacon. The research team analyzed the effects of the food supply chain in the battle against global warming, particularly food production, sales, transportation, storage and service.
In comparison, cabbage produces only one fifth of the pork's gas emissions per calorie. Broccoli's emission footprint per calorie doesn't even reach half of pork's emissions. However, meat favorites such as lamb and beef are worse offenders compared to pork and chicken. When it comes to meat versus vegetable, beef's emission footprint is far worse than lettuce.
The study found a 38 percent increase in energy use, 10 percent increase in water use and 6 percent increase in greenhouse gas emission from the consumption a mix of healthier food choices such as seafood, dairy, fruits and vegetables.
"Lots of common vegetables require more resources per calorie than you would think. Eggplant, celery and cucumbers look particularly bad when compared to pork or chicken," said Paul Fischbeck, social and decisions sciences and engineering and public policy professor.
One of the researchers, civil and environmental engineering PhD student Michelle Tom, stressed the complicated relationship between the environment and the population's diet. Tom added that public health officials need to be aware of the environmental tradeoffs dietary guidelines produce. Findings showed that the environment suffers from what is essentially good for the body.
Chatham House senior research fellow Antony Froggatt commended the study findings. Froggatt, who raised the inclusion of meat tax to aid in the battle against global warming, said the findings confirmed productions of egg, poultry and meat food groups are high contributors to greenhouse gas emissions compared to productions of grains, sugars and vegetables.
Lessening the consumption of eggs, meat and poultry food groups is seen as an opportunity to lessen greenhouse gas emissions. Livestock production make up 15 percent of worldwide greenhouse gas emissions. The proportion is equivalent to the direct emissions from trains, cars, ships and planes combined.
The findings were published in the journal Environment Systems and Decisions on Nov. 24. The research was funded by the Colcom Foundation and the university's Steinbrenner Institute for Environmental Education and Research.
