It’s not just Biden’s farm chief who is treading carefully on livestock emissions: John Kerry, the president’s special climate envoy, rejected the idea that the government will eventually have to tell Americans to eat less meat. “Not necessarily, because there’s a lot of research being done now that will change both the way meat is produced, cattle are herded and fed,” Kerry said in a recent BBC interview. But he also acknowledged that Biden’s aggressive goals for slashing greenhouse gas emissions rely heavily on technology that hasn’t been developed yet. That’s why environmental advocates are pressing for more immediate action. More than two dozen groups petitioned the EPA last month to restrict greenhouse gases from large dairy and hog farms under the Clean Air Act, specifically operations with at least 500 cows or 1,000 hogs.