In a speech to the Oxford Farming Conference, Lucas called for a sustainable food system that restores biodiversity, supports farmers’ livelihoods, upholds animal welfare standards, and contributes to a zero-carbon world.

“At the risk of incurring the wrath of the Energy Secretary who said recently that encouraging people to eat less meat would be ‘the worst sort of nanny state ever,’ I’d add that we need serious consideration of measures like a meat tax,” said Lucas, adding that it would be “offset for more sustainable meat producers through increased revenue from targeted agri-environment schemes.”

Livestock production does account for up to 18 percent of worldwide human-induced greenhouse gas emissions, the New York Times reports. The digestive systems of animals like cows and sheep naturally release methane, and fertilizers used to grow the livestock’s feed can produce nitrous oxide, another harmful greenhouse gas.

While she admitted “better manure management and careful selection of seed can both help reduce greenhouse gas emissions,” Lucas added that a meat tax, particularly on beef, would reduce livestock production and support sustainable meat producers.

Her words may carry some weight: a study by Oxford University researchers found that a meat tax could reduce global greenhouse gas emissions by over 100 metric tons of carbon dioxide equivalent, mostly by reducing beef consumption.

The research, published in Nov. 2018, also said the tax could decrease the number of deaths attributable to red and processed meat consumption by 222,000 and save $41 billion in related health costs worldwide. Other studies have shown that taxes on items like soda, alcohol, and tobacco can influence consumers’ decisions, leading them to a healthier lifestyle.

While vegans and vegetarians may be on board with a meat tax, Phil Stocker, chief executive of the National Sheep Association, argued that even a targeted meat tax would hurt the entire industry—including those farming sustainably.

“Any meat tax would be likely to affect all meat production and consumption—and there are many different forms of meat production,” Stocker told The Guardian, arguing that Britain’s sheep farming “works very much in harmony with our environment, our landscapes, and our human ecology.”