Reduce the Impact of Agriculture
Everything we eat comes from plants, whether we eat the plants directly or through an animal intermediary. The basic problem is that animals are inefficient at converting plants into meat, milk, and eggs. Relatively little of what they eat ends up in what you eat because animals use most of their food to keep them alive – to fuel their muscles so they can stand up and walk around, to keep their hearts beating, to keep their brains working.

That cow, pig, or chicken has to eat a lot more protein, carbohydrates, and other nutrients than it yields in meat, eggs, or milk. The result is that it takes several pounds of corn and soy to produce one pound of beef, or one pound of eggs, one pound of milk, etc. This holds true even if we’re measuring calories or protein; it takes several times the calories or protein in livestock feed to produce the calories or protein we get from the meat, eggs, or milk.

If we're wasting livestock feed, we're also wasting what it takes to grow that feed. This includes inputs like fossil fuels (with all the emissions they produce) to run machinery, to pump water for irrigation, for transportation, and to produce the pesticides and fertilizers. Then there’s the land (= cleared rainforest and grasslands) for growing the crops, along with fertilizers (which produce their own greenhouse gas emissions) and pesticides.

Here's a diagram of the flow of inputs through our human ecosystem. The inefficiency of transferring energy from step to step means each step in the food chain requires a relatively big layer of inputs to support it. So each step you add multiplies the inputs you need at the very bottom (water, land, fertilizer, chemicals).

In any pyramid, taking out a level lets you shrink the base. So, when you cut the livestock step out and eat plants directly, it takes a lot less of the plants to support you. 

You also save the inputs that go into the plants. You save fossil fuels, water, land, fertilizers, and pesticides. You also save extra greenhouse gas emissions from fertilizer and burning fossil fuels, and you save water pollution from chemicals and silt washing off fields into waterways.

And if that’s not enough, you save on the resources used in raising the animals – yet more land and water. You also save the animal waste that is its own pollution problem, not to mention more greenhouse gas emissions like methane from enteric fermentation (a fancy way of saying cow burps).  

All this is why the water it takes to produce the beef on one burger could produce peanuts for about 17 peanut butter and jelly sandwiches, and the land that it takes to produce that beef could produce peanuts for 19 PB&Js. It’s also why the livestock sector is responsible for 18 percent of global climate change, and why you can fight global warming by having a PB&J for lunch.

What about seafood?
It takes a lot of fuel to catch fish. We catch about half our seafood, and that fishing produces a lot of carbon dioxide because fishing boats use a lot of fuel. Catching fish also impacts aquatic ecosystems. Fishing hurts populations of target species like blue fin tuna, along with seabirds, sea turtles, and dolphins (not to mention less-charismatic species) caught as 'bycatch,' which can be two thirds of the catch for shrimp fishing. 

The other half of the seafood is farmed, meaning that it causes the same problems as other animal products if those farmed fish and shrimp eat grain and soy. If the farmed fish eat fish meal (which is made from wild- caught fish), then they cause the same problems as the wild-caught seafood: over-fishing and fuel-related greenhouse gas emissions.

Want to learn more? This page was largely inspired by the Sietch Blog's PB&J discussion. We also especially liked About.com’s discussion in their article about the PB&J Campaign.

Please also check out our Resources  page for more information about how the agriculture and the fishing industries affect the environment.