Free-range isn’t free

Grass-fed beef can have an unexpectedly large environmental cost.

There is no shortage of dire climate news. In addition to reforming energy and transportation, the food system has a critical role to play in preventing unsafe global warming, namely by reducing food waste and producing less meat and dairy.

The most climate-exhaustive food on the planet is beef. Americans presently eat more than 60 pounds of beef per year, and that amount has recently gone up. However, many Americans are left hoping to keep their prized burgers as long as they switch to "better" beef. Celebrity chef Dan Barber recently insisted that Americans could continue their high levels of meat consumption so long as they buy from free-range and grass-fed sources. However, as my colleague and I show in a recent scientific article, grass-fed beef can’t scale sustainably.

Grass-fed cattle can have a larger climate impact than their grain-fed counterparts. Cattle have to ferment grasses in the rumen chambers of their stomachs in order to digest them. The byproduct of grass fermentation is methane.

We would need to breed 23 million more cattle to continue feeding everyone 60 pounds of beef per year. Grass-fed cattle take a longer time to fatten and reach a lower slaughter weight than their grain-fed counterparts. Between the these larger herds and their altered diets, a nationwide shift to grass-fed beef would produce 43% more methane.

What’s more, efforts to reduce the cattle’s footprints by getting them to trample some of their carbon back into the ground rely on shaky science and do not seem to work on a large scale.

Feeding more cattle for longer periods of time would require additional land. Specifically, moving all of our beef cattle off of grain feedlots and out to pastures would require 270% more land than they already use. Cattle already occupy more than a third of the land in the US. We simply cannot hope to feed Americans exclusively grass-fed beef if they don’t also take steps to reduce their consumption. Doing so would either require unsustainably dumping fertilizer and irrigation on US agricultural lands to produce even more grass, or annexing Canada and Mexico.

When all farm animals require vast resources to raise, reducing consumption of animal protein is key. There's simply no way around it: producing meat sustainably requires us to eat much less of it.

This article was reproduced from an earlier version on LinkedIn.