If we really want to cut down on global greenhouse emissions, we're going to have to do something about cow farts*.
That's the conclusion of a study published today in the journal Climatic Change. If we have any shot of reaching the Intergovernmental Panel on Climate Change's global-warming mitigation goals, the world is going to have to start eating a lot less meat.
Thirty-seven percent of all human-caused methane emissions come from the worldwide agricultural industry. Compared with CO2, methane is 21 times more effective at trapping heat in the earth's atmosphere, according to the United Nations. While transportation and electricity account for more than half of emissions in the United States, the EPA reports that agriculture comprises 8 percent of all greenhouse-gas emissions. And while relatively small, that's a significant contribution that can't be ignored — especially considering how progress in halting emissions from transportation has so far been minimal.
"In order to have any chance to reach a 2 degree target, fossil-fuel use has to be reduced drastically," Fredrik Hedenus, the study's lead author, wrote in an email. "However, what we show is that may not be sufficient, as the agricultural emissions ... may be too high. Thus we have to take action in both sectors." Transportation and energy are the biggest sources of greenhouse gases, but researchers say a global shift in people's diets is also necessary to contain climate change."We therefore conclude that dietary changes are crucial for meeting the 2 degree C target with high probability."