The US' current plans to combat change include, among other things, a pledge to cut greenhouse gas (GHG) emissions by 17 percent by 2020 relative to 2005 levels. Whichever way you slice it, that sort of reduction would involve some radical shifts in behavior. A new study has put forth one such suggestion, substituting the entire US population's beef with beans, a dietary change they say would achieve between 50 and 75 percent of this reduction target.

Let's get one thing straight, the entire US population is not going to suddenly stop eating beef. You'd struggle to convince the third-generation Texas barbecue pit master to shut up shop, and you're not going to tell a Yankees fan that they can't have a hot dog at the ball game (those things have got beef in them, right?)

What this study does do, however, is explore the role dietary substitutions could play in helping the US achieve these goals as part of a wide-ranging mitigation strategy. It could mean increasing consumption of faux meat, or upping the concentration of plant-based products in predominantly beef products (think burgers). The figures offered up by the research are simply an extreme example to demonstrate the possibilities.

"Given the novelty, we would expect that the study will be useful in demonstrating just how much of an impact changes in food production can make and increase the utility of such options in climate-change policy," says Loma Linda University's (LLU) Helen Harwat, who led the research.

The researchers started with the fact that beef is the most greenhouse-gas-intensive food item, pointing out that the production of legumes like beans emits one-fortieth the amount of GHGs as beef. Legumes are also a high source of protein. 100 g of beef offers 332 kcals and 14.4g of protein, while 100 g of beans will net you 341 kcals and 21.6 g of protein, according to the researchers.

"Legumes are therefore a natural option for substantially reducing GHG emissions while improving nutrition," the researchers write. "We calculate the net emission change by taking the averted beef emissions and subtracting the emissions associated with producing the legume replacement."

The researchers calculate that if the entire US were to swap out beef for beans, it would cut C02 emissions by 334 million metric tons (mmt) per year. The 2020 pledge requires net emissions to stay below 5,344 mmt a year, compared to the current net emissions of 5,791 mmt annually.

"The nation could achieve more than half of its GHG reduction goals without imposing any new standards on automobiles or manufacturing," says LLU's Joan Sabate, one of the study's co-authors. Food for thought.

The research paper can be accessed online here.