A scientist guides a long tube into the mouth and down to the stomach of Thing 1, a two-month-old calf that is part of a research project aiming to prevent cows from burping methane, a potent greenhouse gas. Paulo de Meo Filho, a postdoctoral researcher at University of California, Davis, is part of an ambitious experiment aiming to develop a pill to transform cow gut bacteria so it emits less or no methane. While the fossil fuel industry and some natural sources emit methane, cattle farming has become a major climate concern due to the sheer volume of the cows’ emissions. “Almost half of the increase in (global) temperature that we’ve had so far, it’s been because of methane,” said Ermias Kebreab, an animal science professor at UC Davis. Methane, the second largest contributor to climate change after carbon dioxide, breaks down faster than CO2 but is more potent. “Methane lives in the atmosphere for about 12 years” unlike carbon dioxide which persists for centuries, Kebreab said. “If you start reducing methane now, we can actually see the effect on the temperature very quickly.” Filho uses the tube to extract liquid from Thing 1’s rumen — the first stomach compartment containing partially digested food.