Your steak may be costing more than you realize, according to a paper in PNAS which estimates that steaks and hamburgers are a significant source of greenhouse gas emissions.

Rising incomes in emerging economies will mean greater demands for meat so it will either become a food solely for rich elites or science improvements will make it less strenuous.

Sustainable cattle ranching policies - brought about by subsidies and taxes - in Brazil could put a big dent in the beef and food industry's greenhouse gas impact, according to the new paper. By subsidizing those who follow mandated use of pastures and taxing those who don't, Brazil could cut its rate of deforestation by half and shave off as much as 25 percent of all global greenhouse gas emissions from deforestation, according to their computer model, which estimated the effects of encouraging "semi-intensive" cattle ranching practices in Brazil. These practices include better management of pasture by rotating where animals graze, planting better grasses more frequently, and amending the soil to unlock more nutrients.

The authors believe that their land management estimates could double productivity of pasture compared to conventional practices, thereby reducing the pressure to cut down more trees. 

"These practices are already used commercially on some ranches in Brazil, but they're not yet cost-competitive because of higher upfront costs, so subsidies can provide a needed boost to make the investment worthwhile," said study lead author Avery Cohn, an assistant professor of environment and resource policy at Tufts University. "We found that it's possible to put policies in place that help good behavior out-compete bad behavior."  

Of course, government mandates and taxes are not actually competition.

Brazil is the largest beef exporter in the world. More than 200 million cattle occupy upward of 494 million acresof land in Brazil, an area almost a quarter the size of the continental United States. Brazil is second, behind the United States, in production of beef. 

Critics blame cattle ranching for 75 to 80 percent of Brazil's deforested areas but that is simplistic. A growing population and people able to afford food has meant lots of other agricultural crops and small farmers living there don't want to live in squalor so rich academics can feel like they have solved global warming. To a smaller extent, mining, logging and housing are also factors.

If 200 million acres of cattle pasture could be used more efficiently, for higher yield cattle ranching or to grow other crops, that could make the difference, they estimate.

"Our study doesn't just ask whether policies affecting beef production will impact deforestation. We're the first to look at Brazil's national policies in an international context by asking what would happen if Brazil did this even if other countries did nothing," said Cohn. "Can the world see benefits from what Brazil does? Our findings indicate that the answer is yes." 

The fuzzier side of cattle ranching estimates

Though estimates vary, beef is a more greenhouse-gas intensive food than plants, because beef eat the plants to become bigger beef, and then the scholars added in their own special sauce of unintended impacts, such as lowering beef prices to the point where people want to consume more, or raising beef prices to the point where beef production is increased elsewhere. 

"We did find that there was some increase in beef consumption with the policies, but one of the big takeaways from this study is that the effect is overshadowed by other gains in reducing deforestation and greenhouse gases," said Cohn.

The authors advocates subsidy and tax policies to help Brazil meet its greenhouse gas reduction targets. 

"There's this notion that fighting climate change requires a stark tradeoff for emerging economies, that they must forego development to meet their emissions target," said Cohn. "This paper suggests that there is a pathway where that compromise may not be needed."