A light caramel liquid shines in a line of flasks in a New Zealand laboratory. It could easily be mistaken for the latest batch of kombucha in the kitchen of a fermentation enthusiast. Except this tangy beverage isn't intended for human consumption – it's for cows. This is Kowbucha, an experimental probiotic culture aimed at altering the mixture of bacteria in the guts of dairy cows and so reduce their impact on the climate.
As cows digest their food they release methane, a highly potent greenhouse gas which, although shorter-lived in the atmosphere, has a global warming impact 84 times higher than carbon dioxide (CO2) over a 20-year period. Methane emissions are responsible for almost a quarter of global warming.
In the most recent report by the UN Intergovernmental Panel on Climate Change (IPCC), scientists warned that "strong, rapid and sustained reductions" in methane emissions are needed in addition to slashing CO2 in the next two decades if the world is to have any hope of keeping warming to within the 1.5C limit set as the ambitious goal in the Paris Agreement on climate change.
Scientists say reducing methane emissions could provide a short-term win for the planet and finding ways to make cows more climate-friendly could consequently be one of the more powerful tools we have to tackle the climate crisis.
Red meat is often pinpointed as a major climate culprit, producing emissions roughly equal to those of India. Livestock generates around 32% of all human-caused methane emissions. Most are produced by the more than 1.5 billion cows on the planet, who belch it out as they digest their food.
But dairy doesn't have the greenest record. According to a study by the Environmental Working Group, cheese generates the third-highest emissions in agriculture, after lamb and beef. It's for this reason that some are questioning whether adopting a vegetarian diet on the grounds of environmental sustainability is all it is cracked up to be.
If milk and cheese have greater emissions than pork or poultry, can an environmental vegetarian justify including them in their diet? Answering this question might soon get easier. In the near future, dairy’s climate costs may be reduced significantly thanks to a suite of innovations that include drawing on the power of the enzymes and microbes found in the guts of cows themselves. And products such as Kowbucha could hold the key.