By Ajit Jha on December 20, 2013 10:05 AM EST

Ruminant animals, like cows, are a more pressing cause of climate change than CO2 emissions, a new study claims. (Photo: Shutterstock)

The focus of climate change target – carbon dioxide emissions – could be lopsided, according to an opinion commentary published in Nature Climate Change. While CO2 emissions are damaging to climate, they are also just a part of the problem; in reality, a more serious cause of climate change are the methane-emitting animals we raise for food. Pound for pound, the two greatest greenhouse culprits are methane and nitrous oxide – both of which trap more heat than CO2 does.

The research team, led by William Ripple from the College of Forestry at Oregon State University, concluded that unless methane and nitrous oxide emissions are curbed along with CO2, we are unlikely to make a real impact on the climate change.

Ripple and his team don’t recommend that CO2 should be ignored or that methane and nitrous oxides alone be targeted, but rather that we need multiple approaches to address the threat of climate change. “We clearly need to reduce the burning of fossil fuels to cut CO2 emissions. But that addresses only part of the problem. We also need to reduce non CO2 greenhouse gases to lessen the likelihood of us crossing this climatic threshold,” Ripple said in a press statement.

Ruminant animals, including cattle, goats, sheep, and buffalo, according to the researchers are primarily responsible for methane emissions. They produce a copious amount of methane in comparison to non-ruminants like pigs and poultry. Ruminants are mammals that have a special, extra stomach that enables them to get more nutrients out of plant-based foods through a process of fermentation prior to digestion.

The ruminant livestock population has grown by 50 percent over the last 50 years. The current current population is estimated at about 3.6 billion, and a full quarter of the planet’s land area goes into their grazing, according to the researchers. We need to reduce the global ruminant livestock populations if we want to curb climate change, the researchers say. Cattle are probably the main targets, since they make up the single largest human related source of protein. The researchers, based on a “farm to fork” analysis, estimated that the cattle produce nearly 19 to 48 times more methane in comparison to protein rich plants such as soy products, beans and grains, on the basis of per pound food produced.

If we can bring down the numbers of cattle, goats, and sheep that we raise – in addition to implementing strategies to reduce direct methane emissions from ruminants – we could make a real dent in climate change, the researchers say. However the implementation of this strategy will likely encounter considerable political resistance, said study coauthor Helmut Haberl of the Institute of Social Ecology in Austria, also in a press release. That’s because people worldwide – especially in the U.S. – are pretty addicted to their red meat, and aren’t likely to comply with any government plans to limit access. And there doesn’t seem to be much international awareness on the issue; it is unfortunate, according to the researchers, that the Kyoto Protocol did not target ruminant emissions.

Other agricultural methods like improved animal genetics to inhibit methane production are still under active research. Simpler “solutions” that could be implemented today, like increasing livestock feeding efficiency or crop yields per acre will not be especially effective, the researchers say. Ultimately, reducing the demand for meat from ruminants does offer the best solution for impactful greenhouse reduction potential. In addition, there are several other benefits of bringing down the number of ruminant livestock as well, such as improved human health, environmental conservation, and food security, according to coauthor Pete Smith of the University of Aberdeen in Scotland.