If we implement wise geoengineering, even eating meat could help tackle the backlog of carbon dioxide in Earth’s atmosphere.
With the right kind of technology, Pollan believes that eating meat can actually be good for the planet. That’s right: Raising livestock, if done properly, can reduce global warming. That’s just one element of a paradigm shift that Pollan and other experts, including Dennis Garrity, the former director general of the World Agroforestry Center in Nairobi, Kenya, and Hans Herren of the Millennium Institute in Washington, D.C., are promoting. They believe that new agricultural methods wouldn’t just reduce the volume of heat-trapping gases emitted by our civilization — they would also, and more importantly, draw down the total amount of those gases that are already in the atmosphere.
"Depending on how you farm, your farm is either sequestering or releasing carbon," says Pollan. Currently, the vast majority of farms, in the United States and around the world, are releasing carbon — mainly through fertilizer and fossil fuel applications but also by plowing before planting. "As soon as you plow, you’re releasing carbon," Pollan says, because exposing soil allows the carbon stored there to escape into the atmosphere.
One method of avoiding carbon release is no-till farming: Instead of plowing, a tractor inserts seeds into the ground with a small drill, leaving the earth basically undisturbed. But in addition to minimizing the release of carbon, a reformed agriculture system could also sequester carbon, extracting it from the atmosphere and storing it — especially in soil but also in plants — so it can’t contribute to global warming.
According to Pollan, photosynthesis is "the best geoengineering method we have."
"When you have a grassland, the plants living there convert the sun’s energy into leaf and root in roughly equal amounts. When the ruminant (e.g., a cow) … grazes that grassland, it trims the height of the grass from, say, 3 feet tall to 3 inches tall. The plant responds to this change by seeking a new equilibrium: it kills off an amount of root mass equal to the amount of leaf and stem lost to grazing. The (discarded) root mass is then set upon by the nematodes, earthworms and other underground organisms, and they turn the carbon in the roots into soil. This is how all of the soil on earth has been created: from the bottom up, not the top down."
The upshot, both for global climate policy and individual dietary choices, is that meat eating carries a big carbon footprint only when the meat comes from industrial agriculture. "If you’re eating grassland meat," Pollan says, "your carbon footprint is light and possibly even negative."