Meat Eater's Guide: Which Animal Products Have the Worst and Best Carbon Footprints?

It's not news that meat and dairy are among the largest contributors to the world's growing carbon footprint, but lamb, beef, cheese, pork, and farmed salmon in particular generate the most greenhouse gases—sometimes four times more than other animal products and 13 times more than plant-based proteins. That's according to a new report from the Environmental Working Group, the Meat Eater's Guide, that assesses the environmental and health impact of our food choices.

It contains some interesting information you might not expect in a report like this. For example, even though cheese is #3 on the carbon footprint list, less-dense cheese is slightly better than harder cheese because it takes less milk to produce. And did you know consumers throw out about 40 percent of the fresh and frozen fish they buy?

The U.S. produced 208 pounds of meat per person in 2009—60 percent more than Europe, according to EWG. Producing all that meat means intensive use of pesticides, chemical fertilizers, energy, and feed. It also means the consumption, and then the pollution, of huge amounts of water.

At current rates, production of meat around the world will double (to about 1.2 trillion pounds of meat per year) by 2050. Our planet cannot afford to supply the water, fuel, pesticides and fertilizer that would require. And public health will deteriorate the closer we get to reaching that mark.

The Meat Eater's Guide: Educating People to Change Habits

To produce the Meat Eater's Guide, EWG and CleanMetrics, an environmental analysis and consulting firm, collaborated to calculate the carbon footprint of 20 types of conventionally (not organically) raised meat, fish, dairy and vegetable proteins, counting emissions generated both before and after the food leaves the farm. Every step of each food's life cycle was accounted for, from the pesticides and fertilizers used to grow animal feed to the grazing, processing, transportation, and cooking—as well as the food waste that gets discarded at the end of it all.

Lamb has the highest emissions, followed by beef, followed by cheese. That's in large part because they come from ruminant animals that generate methane, a greenhouse gas 25 times more potent than carbon dioxide, through their digestive process.

Pork and farmed salmon are next on the list. EWG adds:

With the exception of salmon, they also tend to have the worst environmental impacts, because producing them requires the most resources - mainly chemical fertilizer, feed, fuel, pesticides and water - and pound for pound, they generate more polluting manure. On the health front, the scientific evidence is increasingly clear that eating too much of these greenhouse gas-intensive meats boosts exposure to toxins and increases the risk of a wide variety of serious health problems, including heart disease, certain cancers, obesity and, in some studies, diabetes.

The Impact of Feed Production Alone

Livestock animals in the U.S. consume mostly grain, so that's what the type of feed the guide focuses on. Grain production alone consumes 149 million acres of cropland, 167 million pounds of pesticides, and 17 billion pounds of nitrogen fertilizer, the guide says. Fertilizer applied to soil generates nitrous oxide (N20), which has 300 times the warming effect of carbon dioxide.

Factory-farmed animals also generate about 500 million tons of manure a year, a figure that jumped 60 percent between 1990 and 2008 and has polluted 34,000 miles of rivers and 216,000 acres of lakes and reservoirs throughout the country.

Credit: Environmental Working Group

EWG recognizes this is not the first study of its kind, but it says the Meat Eater's Guide stands out from others because:

Unlike most studies that focus just on production emissions, our assessment calculates the full "cradle-to-grave" carbon footprint of each food item based on the greenhouse gas (GHG) emissions generated before and after the food leaves the farm - from the pesticides and fertilizer used to grow animal feed all the way through the grazing, animal raising, processing, transportation, cooking and, finally, disposal of unused food.