Letitia James is perhaps best known as the New York Attorney General who recently won a US$450 million fraud case against former President Donald Trump and a landmark corruption case against the National Rifle Association.

Now James is taking on JBS , the world’s largest beef producer. The company's reputation precedes it: JBS has faced huge fines in the United States and Brazil for bribery and price-fixing schemes; more than a dozen U.S. senators have tried to block it from issuing stock on the New York Stock Exchange, citing its "extensive international corruption record."

This case, though, is about something else: greenwashing. James claims in a summons that JBS is misleading consumers with claims it could create "bacon, chicken wings and steak with net-zero emissions." ("Net-zero" means overall they wouldn't produce more of the heat-trapping gases that are driving climate change.) Such ads, James says, "in effect, provide environmentally conscious consumers with a ‘license’ to eat beef."

The problem, according to James, is that JBS is making these claims even though it knows that it has no feasible way of achieving them.

She may have a point. For one thing, most of the emissions that come from cattle are in the form of methane, which is a very potent greenhouse gas, especially in the short term. When cows and other ruminants digest carbohydrates, they produce this methane through a process in their stomach known as enteric fermentation. Although people have experimented with various ways to reduce the methane cows emit, such as feeding them seaweed, none have so far proven to be very effective.

And then there is the land-use change, which is what the IPCC calls it when a forest is cut down to make way for pasture or other agricultural land. Among the most concerning examples is the destruction of the Amazon rainforest. And as the largest purchaser of cattle from that region, JBS is responsible for much of it.

In fact, in 2021, JBS reported that it was responsible for emitting the equivalent of 71 million tonnes of CO₂. As James memorably notes in her lawsuit, that’s "more than the total emissions from the country of Ireland during the same year."

This will be an interesting lawsuit to watch. According to a 2023 FAO report, livestock production and related land-use change accounted for around 12 percent of all anthropogenic greenhouse gas emissions in 2015. Now this suit will ask a court of law to consider whether there is any technology or farming system that can ever bring those emissions to zero or net-negative.

(You can watch George Monbiot and Allen Savory debate this topic here.)