It’s long been believed that livestock and global warming can be linked to each other. A new study, however, suggests that people might have been too conservative in estimating the amount of methane released by cows and other animals, and its impact on our environment.
As noted by the Washington Post, it is generally accepted that carbon dioxide, the “most important warming agent” in climate change, mainly originates from the burning of fossil fuels, with other factors, such as deforestation, playing a part in these emissions. Methane, on the other hand, comes from more ambiguous sources, which makes the recent rise in atmospheric methane levels especially concerning. Some experts have pointed to fracking as the main reason behind this rise, while others have suggested that agriculture should be blamed for higher atmospheric methane levels.
In a study published Thursday in the journal Carbon Balance and Management, a team of scientists looked at the possible link between livestock and global warming. According to lead author Julie Wolf, a plant physiologist from the U.S. Department of Agriculture, livestock methane emissions were responsible for a significant 11 percent increase in overall methane levels “in a recent year,” as compared to previously estimated figures. Forbes wrote that these earlier figures were used as a basis for the 2006 Intergovernmental Panel on Climate Change.
“[Livestock methane emissions are] not the biggest contributor to the annual methane budget in the atmosphere, but it may be the biggest contributor to increases in the atmospheric budget over recent years,” said Wolf in a statement.
The impact of livestock on global warming had long been underestimated, based on the study’s results, Forbes wrote. Wolf and her colleagues discovered that some of the low estimates had dated back multiple decades, which suggested that the older statistics did not consider variables such as land and animal use. Furthermore, Wolf added that breeding has resulted in larger animals who require more food, and when that is combined with today’s trends in livestock management, both factors can also result in higher methane emissions.
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Considering a few other present-day observations, which included the decreasing reliance on cattle to pull farm equipment, and the likelihood that manure will be stored in open pits rather than used as fertilizer on the fields, Wolf and her team believe that livestock emissions resulted in about 120 million additional grams of methane.
The storage of manure in large pits, in particular, was cited as a key driver in the higher-than-expected livestock methane emission levels, as this process causes bacteria to create twice as much methane than usual. The researchers estimated a 36.7 percent increase in global methane emissions, as compared to the IPCC’s 11-year-old estimate, as a result of the above process. The levels of methane produced when cattle and other animals pass gas was also higher, but not by that much, as levels were estimated to be 8.4 percent greater than the figures on record.
Going forward, Wolf hopes that her team’s research and new estimates will encourage scientists and other decision-makers to come up with more precise figures and more accurate research regarding the link between livestock emissions and global warming.
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