Scientists at Bristol University have proposed an alternative method of evaluating livestock emissions that more accurately reflects the nutritional benefits of beef.
They claim that incorporating a measure known as Recommended Dietary Intakes (RDIs) into the emissions metric would see beef compare more favourably with other meats.
The difference is huge, with beef production accounting for lower emissions than free-range chicken under the recalculation.
The measure was explained by environmental consultant Sarah Jones in an article on Promar International’s website.
“The current focus on cattle production over-simplifies what is a very complicated subject,” said Ms Jones.
Much of the argument around livestock farming focuses on the global warming potential (GWP) of meat and dairy thanks to greenhouse gas production by animals, she explained.
For each 100g of meat produced, beef cattle create almost 2kg of carbon dioxide equivalent (CO2e) – the standard unit for measuring carbon footprints.
When compared with intensively reared chicken, which produces less than 0.5kg CO2e per 100g of meat, cattle appear to be much less environmentally friendly.
But this simplistic measure fails to grasp the nutritional output being achieved within each kg of meat compared with the CO2e, Ms Jones said.
New work on emissions
She highlighted the work carried out by Bristol University sustainable agriculture expert professor Michael Lee which was presented at the Sustainable Food Trust’s recent conference.
Professor Lee developed the new approach to measuring GHGs in beef production by incorporating RDIs.
At the conference Prof Lee explained that people didn’t eat to consume kilos of a product, they ate to consume the nutrients they needed.
The RDI system recognises this fact and accounts for beef’s high nutritional value per kg and its concentration of vital vitamins and minerals such as omega-3 fats and vitamin E.
This then allows a better comparison to foods which have much lower nutrient levels per kg, yet on the surface, have a lower carbon footprint, Ms Jones said.
Scientists using this metric have revealed that emissions from beef cattle reared on concentrates are actually less than 0.05kg CO2e per 1% of RDI.
That is just a fraction of the 2kg CO2e per 100g calculated in the standard GWP measurement, said Ms Jones.
Factoring in the nutritional value showed that emissions from those same cows were 2.25-times lower than free-range chicken.