Meat Eaters Guide: Methodology - Environmental Working Group

Meat Eaters Guide: Methodology
20
• Overall Efficiency of the Agricultural Operation: Greater yields per input will naturally
result in lower GHGs; more productive agricultural systems tend to produce the fewest GHGs
per unit. This is perhaps one of the most important factors that could change the relative
GHGs of a given operation. However, in some cases efficiency gains can be counteracted by
unintended consequences. For example, feed production efficiency gains could be achieved
by increased fertilizer use, which could in turn lead to increased nitrous oxide emissions. 36
• Nutritional quality and digestibility of feed: High quality diets (based on ingredients such
as corn and soy) will result in lower methane emissions from the cow’s digestive process
compared to lower quality, higher-fiber diets consisting of grass and hay. 37
• Manure Management Practices: Solid manure storage will have lower methane emissions
than open pit or liquid manure systems; ensuring that manure is then spread on fields in an efficient
manner (not overusing manure and assuming no precipitation) will also reduce the N 0 2
emissions from application of manure. 38
• Grazing Practices: Intensive grazing (whereby animals are regularly moved to fresh pasture
to maximize the quality and quantity of forage growth) generates fewer GHGs than the more
common practice of extensive grazing. 39 Other best management practices, such as the use
of soil amendments, could result in steady sequestration of carbon by pastureland and would
reduce the overall emissions of this stage of the process. 40
• Soil Management Practices: Various best practices in soil management, such as cover
cropping and composting, result in lower emissions by building soil organic carbon. At the
same time, reducing fertilizer use for growing feed (especially corn) could result in decreases
in energy use from fertilizer production as well as decreases in nitrous oxide emissions. 41
Since feed production contributes a sizable amount to the overall carbon footprint of meat,
best management practices in fertilizer application could be an important way to reduce GHG
emissions.
• Freezing: Whether a product is frozen or not has an important impact on post-farmgate emissions
but not on a product’s overall emissions. For example, consuming fresh rather than
frozen beef reduces its GHG emissions by less than 3 percent.
• Cooking: The length and type of cooking has an important impact on post-farmgate emissions.
For example, a baked potato has a much higher GHG impact than French fried
potatoes, since French fries are cooked in about 5 minutes while a baked potato takes about
an hour. 42 However, cooking accounts for a relatively small portion of the overall footprint in
the case of animal products (about 4 percent in the case of beef).
• Waste: The percentage of food that is wasted along the supply chain has a dramatic impact
on the carbon footprint of food when all the inputs that went into producing that food are considered.
Whether a food item is composted or sent to the dump also has an impact, but not
nearly as much as the actual amount of food discarded. According to our model, composting
beef rather than tossing it in the garbage reduces the overall carbon footprint by .4 percent
(26.93 CO if beef is composted instead of 27.02 if it is tossed in the landfill).
2
Environmental Working Group Meat Eaters Guide: Methodology 2011