July 19 (UPI) -- Wild pigs emit as much carbon from global soil annually as 1.1 million cars, a new study found.
An international team of researchers said in the study, published Monday in the journal Global Change Biology, that most of the Earth's carbon is stored in soil, which can be uprooted as carbon dioxide.
The researchers used predictive population models to estimate the damage and soil carbon emission release caused by wild pigs, determining they were uprooting around 36,000 to 124,000 square kilometers -- roughly 14,000 to 48,000 square miles -- in areas where they are not native.
"This is an enormous amount of land, and this not only affects soil health and carbon emissions, but it also threatens biodiversity and food security that are crucial for sustainable development," study author Dr. Christopher J. O'Bryan said in a press release on the study.
The soil disturbance from wild pigs results in median emissions of 4.9 million metric tonnes of carbon dioxide each year across the globe, equivalent to 1.1 million cars, or .4% of annual emissions from land use, land-use change and forestry, the study found.
"Wild pigs are just like tractors plowing though fields, turning over soil to find food," said O'Bryan, a researcher at the University of Queensland in Brisbane, Australia.
"Since soil contains nearly three times as much carbon than in the atmosphere, even a small fraction of carbon emitted from soil has the potential to accelerate climate change."
Humans have already worsened soil carbon emissions through land-use change, researchers said in the study, which sought to determine impact from wild pigs as an invasive species.
University of Canterbury doctoral candidate Nicholas Patton, a co-study author, said human beings have been part of the problem and should be part of the solution.
"Invasive species are a human-caused problem, so we need to acknowledge and take responsibility for their environmental and ecological implications," Patton said in the press release.