Knowledge for better food systems

Meat Eater's Guide to Climate Change and Health

The US based non profit organisation Environmental Working Group has published its report entitled  Meat Eater’s Guide to Climate Change and Health. The report was undertaken for EWG by the Life Cycle Analysis consultancy CleanMetrics (See outbound link).

The US based non profit organisation Environmental Working Group has published its report entitled  Meat Eater’s Guide to Climate Change and Health. The report was undertaken for EWG by the Life Cycle Analysis consultancy CleanMetrics (See outbound link).

The report calculates the greenhouse gas emissions associated with the production and supply of various meat and dairy foods along their whole life cycle, including agricultural production, processing and distribution, retailing, food consumption in the home, and waste. As regards waste, it calculates the GHG emissions associated with the amount of a given product that is needed to produce 1 kg of consumed product  (for example if people on average waste 20% of a given product, and if 100g of said product is actually consumed then the overall amount for which emissions need to be calculated is 125g, since 100g is 80% of 125g). For comparison, emissions for some plant based protein alternatives are also calculated (eg. lentils).

Key findings are as follows:

Emissions from agricultural production

Lamb, beef and cheese have the highest GHG emissions:  This is due, in part, because they because they generate methane emissions. Kilo for kilo, ruminants also require significantly more energy-intensive feed and generate more manure than pork or chicken

  • Lamb has the greatest impact, generating 39.3 kg of CO2 eq for each kilo eaten – about 50% percent more than beef. While beef and lamb generate comparable amounts of methane and require similar quantities of feed, lamb generates more emissions per kilo in part because it produces less edible meat relative to the sheep’s live weight. Since just one percent of the meat consumed by Americans is lamb, however, it contributes very little to overall U.S. greenhouse gas emissions.
  • Beef has the second-highest emissions, generating 27.1 kg CO2 eq per kg produced. That’s more than twice the emissions of pork, nearly four times that of chicken and more than 13 times that of vegetable proteins such as beans, lentils and tofu. About 30 percent of the meat consumed in America is beef.
  • Cheese generates the third-highest emissions, 13.5 kg CO2e per kg eaten. Less dense cheese (such as cottage) results in fewer greenhouse gases since it takes less milk to produce it.

Relative contribution of primary prodution to overall life cycle impacts

90% of beef’s emissions, 50% of chicken’s, 69% of pork’s, 72% of salmon’s and 68% of tuna’s are generated in the production phase. In the case of beef and dairy, this is due to enteric methane emissions as well as N2O from feed production. Chickens are less GHG intensive to rear bull as the nitrous oxide generated from growing feed. Chickens, in contrast, generate no methane and have far fewer emissions during production. In the case of farmed salmon, the primary emissions in the pro more energy and water intensive to process than any other meat. Emissions for farmed salmon are also high because consumers throw away a lot of what they buy. This means that a lot of additional salmon is produced for every kg that gets eaten.

Sources of greenhouse gases are different for farmed and wild fish. Feed production dominates emissions from salmon farming, while diesel combustion from fishing boats accounts for most of the emissions from wild-caught fish, including salmon and tuna. Overall, canned tuna has lower emissions. This is partially due to the fact that tuna and other wild-caught fish live on food that they consume directly from the ocean, in contrast to farmed fish that are fed energy-intensive feed (such as sardines, menhaden, soybean meal and wheat) that must be grown and/or caught. Also, this analysis considered canned tuna vs. fresh (farmed) salmon, keeping tuna emissions lower because there is less waste and no cooking in the canning process.

In contrast to meat, most of plant proteins’ emissions are generated after crops leave the farm (processing, transport, cooking and waste disposal). Post-farmgate emissions account for 65% of dry beans’ total emissions and 59% of lentils’, primarily because of the energy needed to cook them. Using a pressure cooker that cuts cooking time in half reduces beans’ emissions by 25%. 90% of potato emissions occur after the crop leaves the farm, primarily from cooking.

Food waste

Discarded food accounts at least 20% on average of the emissions associated with producing, processing, transporting and consuming meat and dairy products.

Most of the emissions attributed to waste come from producing food that is ultimately discarded – from fertilizer and pesticide production, growing feed, transportation, etc. Foods with higher waste rates such as farmed salmon (44 percent is thrown away by retailers and consumers) have much higher emissions during production since it takes a lot more salmon to produce the amount that is actually consumed.  Some of the waste-related production emissions are unavoidable, such as moisture and fat loss during cooking. These must be accounted for in the lifecycle analysis, but there is very little consumers can do to minimize these losses.

The amount of food consumers throw away varies considerably. Consumers throw out about 40% of the fresh and frozen fish they buy, but only 12% of the chicken, 16% of the beef, 25% of the pork, and 31% of turkey is discarded at home or in restaurants. On average, retailers throw out about 5% of the meat they sell.

Processing emissions

Processing accounts for just 5% of lamb and beef’s overall carbon footprint, compared to 12% pork’s and 24% of chicken’s.

Impacts of shifting to a vegetarian diet

If everyone in the U.S. chose a vegetarian diet, it would only make a moderate dent in overall carbon emissions, about a 4.5 percent reduction. Other estimates of meat’s overall contribution to US emissions are higher, but not as high as many estimates for the world as a whole.  This is because the U.S. has other very large other industrial sources of greenhouse gases, making the meat slice of carbon emissions comparatively smaller. Also, U.S. livestock production does not depend on cutting down carbon-rich rain forests in order to import or grow feed crops and raise animals, as is true in Europe (which imports significant amounts of feed from Brazil) or in some tropical countries, where livestock emissions are a much larger slice of the overall emissions pie.

While important, it is clear that making significant cuts in US emissions will not come solely from individual action. It will take political action to bring about comprehensive policies that put the nation on a path to green energy. Similarly, reducing meat production’s negative impact on soil, air and water quality will require better policies and regulatory enforcement as well as curbing meat consumption.

Health effects of dietary shift

Chronic diseases: the report highlights the role of meat in contributing to excess calorie intakes, leading to obesity and associated chronic diseases (such as cardiovascular diseases, strokes etc).  In particular it highlights research linking  It also highlights research linking red and processed meat consumption with chronic diseases including some cancers.

Antibiotics, hormones, environmental toxins: It also highlights health concerns associated with antibiotics use in livestock production (leading to antibiotics resistance) and of growth promoting hormones (linked to some cancers and neurological illnesses), environmental toxins – particularly in farmed fish, including dioxin like compounds and mercury.

Overall conclusions

Its overall conclusions are that eating and wasting less meat (especially red meat) and cheese can simultaneously improve health and reduce the climate and environmental impact of food. Although the study does not base its analysis on a comparative assessment of conventional versus organic meat production, it draws the conclusion that eating meat and dairy products from organic, grass fed and pasture raised animals is better for personal health and for the environment.

You can download both the EWG report and the LCA analysis by CleanMetrics that underpins it here.




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FCRN Admin's picture
Submitted by FCRN Admin on

Thanks for the update Christian! Will amend now...