The Dung Beetle Is a Climate Change Hero

By: By Terrell Johnson

Published: August 28, 2013

DRAGO PRVULOVIC/AFP/Getty Images

If humans one day are able to bring greenhouse gas emissions under control and forestall the worst impacts of global warming, they may have an unlikely hero to thank.
The lowly dung beetle, which feeds on animal feces and is found on every continent save Antarctica, helps reduce the amount of methane released into the atmosphere from farms by doing what it does best -- burrowing into cow patties and other animal droppings.
That makes it a surprisingly effective weapon in the battle against climate change, notes a study released this month in the science journal PLOS ONE, because methane is one of the most potent of the heat-trapping greenhouse gases.
"We believe that these beetles exert much of their impact by simply digging around in the dung," said Atte Penttilä, a masters student at the University of Helsinki and one of the study's co-authors, in a press release.
"Methane is primarily born under anaerobic conditions, and the tunneling by beetles seems to aerate the pats," he added. "This will have a major impact on how carbon escapes from cow pats into the atmosphere."
Agriculture -- and cattle farming for meat and milk in particular -- is one of the biggest sources of man-made greenhouse gas emissions worldwide, accounting for between "35 to 50 percent of extremely potent methane," notes the Atlantic magazine. This makes the dung beetle's ability to scrub the air clean of at least some of these emissions an unexpected gift.
The discovery came after the study's scientists (from Oxford University and the University of Helsinki) collected cow patty samples from fields in northern Europe and placed beetles alongside them in rows of containers, to measure the vapors they released.
After several weeks, their results were conclusive: "The manure without beetles in it produced higher amounts of methane -- on one special day, as much as five times what wafted off the insect-loaded dung," the Atlantic reports.
The results were encouraging but also worrying, explained Tomas Roslin, the head of the research team. "If the beetles can keep those methane emissions down, well then we should obviously thank them -- and make sure to include them in our calculations of overall climatic effects of dairy and beef farming," he said.
However, noted researcher Eleanor Slade, "when you combine the current increase in meat consumption around the world with the steep declines in many dung beetle species, overall emissions from cattle farming can only increase."

 

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A caribou walks in the foreground of a glacier on July 12, 2013, in Kangerlussuaq, Greenland. (Joe Raedle/Getty Images)