In 2009, celebrity vegan Paul McCartney launched nonprofit group Meat-Free Monday to encourage people to devote a day a week to swearing off meat. The group cites a conservative estimate from the Food and Agriculture Organization of the United Nations that pins 14.5 percent of global greenhouse emissions on livestock production, while other estimates have ranged as high as 51 percent.

On May 9, former US President Barack Obama delivered a keynote address at the Global Innovation Summit in Milan, Italy, where he stressed the importance of changing food habits on a global scale to curb global warming.

Foremost, according to Obama, is reducing food waste. Beyond that, he suggested having “a smaller steak.” We can “make progress in educating the advanced world about the need to reduce,” he added, “the amount of meat that we consume at any given meal.”

According to a 2012 study in Environmental Research Letters, stabilizing greenhouse gases by 2050 requires, among other efforts, “a 50 percent reduction in mean per capita meat consumption in the developed world.”

While meat consumption per capita in the developed world is estimated to increase by little more than 10 percent from 1990 to 2030, for the developing world it is estimated to more than double, according to figures from the FAO.

By Kevin Lee Selzer (klselzer@heraldcorp.com)