Posts Tagged ‘Life-cycle assessment’

picture-143At 200 pounds each per year, Americans eat more meat per capita than any other people in the world. Unfortunately for the rest of the world, they’re catching up with us – and when they do, we’ll need two-thirds more land than exists on the planet to meet the higher demand.  The world’s huge production of meat, eggs, fish and dairy is causing a head-on collision between demand for these items and the reality of scarce resources like land, water, and fossil fuels. This isn’t a future threat; it’s happening in real time, right now. It takes up to one hundred times more water, eleven times more fossil fuels, and five times more land to produce animal protein than equal amounts of plant protein.[1] Further, animal food production is now the planet’s single biggest cause of climate change.[2] The machinery of industrial farming is bursting at the seams, spilling animal emissions and production by-products across all environmental media—air, water, and land. In this three-part series, I explore several popular ideas proposed to address the challenge of producing animal foods sustainably: local consumption, organic production, and fish farming. An in-depth look at these proposals seeks to answer the question: can animal foods be produced sustainably?

Part One: Loco for Local

Sustainability, some insist, requires that we consume food raised locally. Food’s carbon footprint is measured using a technique called “life cycle assessment” (LCA), which examines the carbon impact of every step or component in a food item’s production and consumption. LCA measures water use, harvesting methods, packaging materials, storage and preparation techniques, and other factors. But spoiling the local food movement’s heavy emphasis on what it calls “food miles” is the fact that transportation averages only 11 percent of total carbon footprint and is thus a mere fraction of most edible items’ LCA.[3] By contrast, the act of cooking food typically accounts for 25 percent of its carbon footprint, while production accounts for another 17 percent of the carbon footprint.[4] In other words, a modest efficiency or inefficiency in either production or cooking can easily outweigh transportation’s entire effect.

Hann_lambThe LCA data lead to some startling conclusions about food miles and the merits of local consumption. For example, one study found that it’s more carbon friendly for the British to buy lamb from New Zealand than to buy locally.[5] Lamb production is much more energy efficient in New Zealand than in the UK, in part because British production relies on fossil fuels while New Zealand production uses 64 percent renewable fuels. Thus, British lamb production requires 45,859 megajoules (MJ) of energy per ton of meat, while New Zealand production takes only 8,588 MJ per ton. Even after adding in the 2,030 MJ of energy needed to ship the New Zealand meat to the UK, New Zealand is still the clear winner at only 10,618 MJ for both transport and production—less than one-quarter of the British production requirement. This difference in energy consumption means New Zealand also wins in CO2 output related to lamb production—just 688 kg/ton compared to the UK’s 2,849 kg/ton.[6]

2months-lactation-breeding-1-1In another example of Kiwi production efficiency, the same study found it’s more carbon friendly for Brits to buy their powdered milk from New Zealand instead of locally. New Zealand dairy cows are generally pastured and eat grass, while British cows are mostly confined and eat forage feed like hay and nutritional supplements known as concentrates. The fuel inputs needed to produce the British cows’ forage feed and concentrates lead to major efficiency differences in milk production between the two countries. Thus, it takes 48,368 MJ of energy to produce a ton of powdered milk in the UK, but only 22,912 MJ in New Zealand. Even adding the 2,030 MJ necessary to transport the Kiwi powdered milk to the UK, the total energy used for both production and transport of the New Zealand product is 24,942 MJ—about half that in the UK. Again, New Zealand’s lower energy use means less CO2 output: just 1,423 kg to produce and deliver a ton of powdered milk to the UK, versus the British emission of 2,921 kg of CO2 to produce the same ton of product.[7]

As these examples show, placing too much emphasis on food’s local origin can easily cause one to overlook LCA components that have a greater effect on the environment. Such results led the New Zealand study’s authors to criticize the practice of equating food miles with carbon footprint—a practice they say “ignores the full energy and carbon emissions from production.”[8] The moral here isn’t that we should completely ignore food miles in measuring food’s ecological impact; we just need to exercise more discretion in how much importance we give those miles. As Texas State University professor James McWilliams observes in his book Just Food:

Sure, it feels righteously green to buy a shiny apple at the local farmers’ market. But the savvy consumer must ask the inconvenient questions. If the environment is dry, how much water had to be used to grow that apple? If it’s winter and the climate is cold, was the apple grown in an energy-hogging hothouse? Is the local fish I’m ordering being hunted to extinction? . . . Distance, in other words, is just a minor factor to consider. In overemphasizing food miles, we have missed important opportunities to think more critically about the fuller complexities of food production.[9]

group-of-fruits-and-vegetablesLocal consumption, then, is not the cure-all to solve the sustainability problems of meat and dairy production. If you eat animal foods, to some extent you might help support small farmers by buying locally. But as we’ve seen, the carbon calculations are complicated, and local buying is often not the most eco-friendly way to consume. (The only truly eco-friendly foods, of course, are plants.) In the next installment, we’ll look at organic production as a potential means to address the problem. Stay tuned!  For more surprising information on this and other issues related to animal food production, check out my just-released book Meatonomics: How the Rigged Economics of Meat and Dairy Make You Consume Too Much – and How to Eat Better, Live Longer, and Spend Smarter (Conari Press, 2013).

[1] David Robinson Simon, Meatonomics: How the Rigged Economics of Meat and Dairy Make You Consume Too Much—and How to Eat Better, Live Longer, and Spend Smarter (San Francisco: Conari Press, 2013).

[2] Robert Goodland and Jeff Anhang, “Livestock and Climate Change: What if the Key Actors in Climate Change Are . . . Cows, Pigs and Chickens?” World Watch (November/December 2009): 10–19.

[3] Christopher L. Weber and H. Scott Matthews, “Food-Miles and the Relative Climate Impacts of Food Choices in the United States,” Environmental Science and Technology 42, no. 10 (2008): 3508–13.

[4] Rich Pirog et al., “Food, Fuel, and Freeways: An Iowa Perspective on How Far Food Travels, Fuel Usage, and Greenhouse Gas Emissions,” Leopold Center for Sustainable Agriculture (2001).

[5] Caroline Saunders and Andrew Barber, “Carbon Footprints, Life Cycle Analysis, Food Miles: Global Trade Trends and Market Issues,” Political Science 60, no. 1 (2008): 73–88.

[6] Ibid.

[7] Ibid.

[8] Ibid., 87.

[9] James McWilliams, Just Food: Where Locavores Get It Wrong and How We Can Eat Responsibly (New York: Back Bay Books, 2009), 214.