bad bad bad bovines!


Upwithclimate member Brian Machovina has just published another short article highlighting the dangers of increasing meat consumption for conservation.  The article, which is entitled “Meat consumption as a key impact on tropical nature”, was published in the journal Trends in Ecology and Evolution (TREE) as a response to a previous article by Bill Laurance et al. discussing the impacts of agriculture in general on tropical conservation.  A copy of Brian’s article is included below. Interestingly, another paper was published near-simultaneously in PNAS by Eshel et al. discussing the “Land, irrigation water, greenhouse gas, and reactive nitrogen burdens of meat, eggs, and dairy production in the United States”.  This paper reinforces Brian’s ideas and shows that “…the environmental costs per consumed calorie of dairy, poultry, pork, and eggs are mutually comparable but strikingly lower than the impacts of beef. Beef production requires 28, 11, 5, and 6 times more land, irrigation water, GHG [greenhouse gas emissions], and Nr, respectively, than the average of the other livestock categories. Preliminary analysis of three staple plant foods shows two- to sixfold lower land, GHG, and Nr requirements than those of the nonbeef animal-derived calories…”  In other words, meat is bad, but beef is the food of the devil.

Meat consumption as a key impact on tropical nature: a response to Laurance et al.
By: Brian Machovina & Kenneth J. Feeley

Laurance et al.’s review “Agricultural expansion and its impacts on tropical nature” provides a valuable summary of how agricultural is affecting the diversity of tropical terrestrial and aquatic ecosystems. However, we believe that a major factor driving the loss of tropical ecosystems and biodiversity was not given sufficient attention and deserves further discussion. Of the eight points discussed by Laurance et al. as “key challenges ahead,” no mention was made of the challenges posed by increasing per capita meat consumption. We argue that rising levels of meat consumption globally, and in developing tropical countries in particular, is one of the greatest threats to tropical ecosystems and biodiversity.

Although some agricultural expansion is driven by farmers growing crops for direct human consumption, livestock production accounts for up to 75% of all agricultural lands and 30% of Earth’s land surface, making it the single most expansive anthropogenic land use.  Of the seventeen megadiverse countries – a group of countries that collectively harbor the majority of the Earth’s species – fifteen are developing tropical countries and eleven of these have increasing rates of per capita meat consumption.

China, one of the megadiverse countries, will have a strong impact on human diet-driven ecosystem and biodiversity loss by causing rapid and extensive habitat destruction well beyond its borders.  China currently houses approximately 20% of all human beings and has a relatively-low but rapidly-rising rate of per capita meat consumption (10% of diet in 1989; 20% in 2009; on trajectory to reach 30% by 2030 with a projected 1.5 billion inhabitants). Much of China’s livestock production is fed on soy grown in the Brazilian Amazon. In Amazonia, at least 80% of all deforested lands have been converted to pasture, and much of the remaining deforested areas are dedicated to export feedcrop production. Feedcrop production is projected to grow in the Amazon, with Brazil predicted to increase soybean harvests from 60 to 95 million metric tons annually between 2010 and 2030.

A rise in meat consumption is not necessary nor is it inevitable. Increasing levels of meat consumption is connected with elevated incidences of many diseases. Diets rich in fruits, vegetables, and plant-based protein sources are healthier than those containing a higher proportion of meat and dairy products.  Eliminating livestock and growing crops only for direct human consumption could increase the amount of calories that can be produced on extant agricultural lands by an estimated 70%.  This could feed an additional 4 billion people – significantly more than the projected global population growth of 2–3 billion. Much of the future population growth will occur in developing countries where low-cost, locally-available and environmentally-sensitive practices and technologies can improve production of plant-based food sources and provide necessary caloric, protein, and nutrient levels.

Based on a balance between the need to increase nutritional health and availability of calories with the need to decrease the land demands and ecological footprint of agriculture, we argue for a goal of significantly reducing the contribution of animal products in the human diet, ideally to a global average of 10% or less (this is roughly equivalent to limiting daily consumption of meat to a portion that is approximately the size of a deck of playing cards or smaller). Within the context of decreasing total meat consumption,  the spatial and climate change footprint of agriculture  can be further reduced by the preferential use of meat sources with higher energy conversion efficiencies (i.e. chickens > pigs > ruminants) and a switch to more-efficient production methods.

Reaching the proposed goal will require significant decreases in per capita meat consumption by developed countries and little or no increase in developing countries.  For example, animal products currently comprise approximately 48% of the average diet in the USA. Developing countries will need to resist emulating the animal-product rich diets of developed countries and stabilize meat consumption near their current levels. Reducing the total per capita consumption of meat and increasing the proportion of meat that is derived from more-efficient sources will enable developing tropical countries to feed more people on less land even if total caloric and protein intake increase, hence maintaining human wellbeing and reducing threats to biodiversity. Without a global per capita decrease in meat consumption, the successful conservation of Earth’s remaining tropical ecosystems, and the great biodiversity that they contain, is almost certain to fail.

[Literature citations have been removed to improve clarity but are available upon request]

Machovina, B. & Feeley, K.J. Meat consumption as a key impact on tropical nature: a response to Laurance et al. Trends in Ecology & Evolution, 29, 430-431. Available online


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