Lowering methane emissions in Australia may come from stopping cow burps, the Australian Broadcasting Corporation announced. Scientists are farming a species of puffy, pink seaweed and introducing it to the bovine food regimen. Methane sources are far below and high above us, and it’s a problem.
According to the ABC article, by adding a small amount of the seaweed species asparagopsis to cattle diets, Australian farmers can reduce the methane gas the animals produce by 99 percent. Overall, mass farming and implementation of the seaweed species could reduce the country’s greenhouse gas emissions by a full 10 percent. Methane is a small hydrocarbon molecule (CH4) found all around us, sometimes to our global environment’s detriment.
The Sources of Methane
So where does methane come from? The leading theory revolves around microbes living in the sea. “There is no controversy that some methane deposits result from ‘methanogenic’ microbes that release methane as part of their normal metabolic cycle,” said Dr. Robert M. Hazen, the Clarence J. Robinson Professor of Earth Sciences at George Mason University. “These methanogens thrive in oxygen-poor ocean sediments that are found near many known methane reserves. Some very large and shallow natural gas deposits are thought to have formed by the sustained action of these microorganisms.”
And these microbes aren’t exactly hard to find. “It turns out that just about anywhere you dig or drill into the Earth’s crust, whether on land or at sea, there are microbes living in the subsurface,” Dr. Hazen said. “Microbes have been found in drill cores as deep as three miles and they seem to thrive in deep sediments and in solid rocks, anywhere there is subsurface water, as long as the temperature is below 130 degrees Celsius.”
However, methane-producing microorganisms aren’t the only part of the biological methane equation. “When biomass is deeply buried and subjected to temperature and pressure, methane is often produced as a byproduct,” Dr. Hazen said. “This so-called ‘thermogenic’ methane is very commonly associated with both petroleum and with coal deposits.” It’s from this thermogenic methane that we see fires burning off atop oil derricks, he said. The same goes for gas explosions in coal mines.
From the Sea to the Sky
As this methane builds and reacts to other molecular compounds deep in the ocean—as well as frigid, deep-sea waters—they form ice-like crystals called methane clathrate. According to Dr. Hazen, if the ocean waters or tundras that contain the shallowest deposits of methane clathrate warm even slightly, the crystals can melt and release large amounts of methane into the atmosphere. This methane increases the greenhouse effect, causing more warming, which causes more methane release, in a dangerous cycle.
“Some scientists now point to a possible catastrophic Neoproterozoic release of ocean floor methane as a way to accelerate global warming, perhaps flipping Earth from cold to hot in a matter of decades,” Dr. Hazen said. “Looking back at the Neoproterozoic hothouse Earth episodes, many scientists suggest that a sudden release of methane from shallow clathrates contributed to the warming in exactly this way. In a geological blink of an eye—perhaps much less than a thousand years—the climate lurched.”
Compared to the vast quantities of methane solidifying into methane clathrate crystals and causing greenhouse gas emissions, cow burps may seem like small potatoes. However, the simple act of changing bovine diets could help slow down the global warming that’s causing the clathrate to melt in the first place, which could prove beneficial in the long run.
Dr. Robert M. Hazen contributed to this article. Dr. Hazen is Clarence J. Robinson Professor of Earth Sciences at George Mason University in Fairfax, VA. He earned his bachelor’s and master’s degrees in geology from the Massachusetts Institute of Technology. He earned a Ph.D. in Earth Science from Harvard University.