Elsevier

Ecological Economics

Volume 23, Issue 3, 5 December 1997, Pages 189-200
Ecological Economics

METHODS
Environmental sustainability in agriculture: diet matters

https://doi.org/10.1016/S0921-8009(97)00579-XGet rights and content

Abstract

There is no agreement that diet matters for environmental sustainability in the agriculture sector. Much current agriculture is unsustainable and worsening; the environmental impact of agriculture degrades natural capital (e.g. loss of topsoil, waste and pollution of water, nutrient loss, extinction of species). Cattle raising is one of the most damaging components of agriculture. Livestock now eat about half of global grain production. There is limited scope for improving food supply and what scope there is will further damage the environment. All means to improve nutrition, especially for the poor, will be needed as population increases. One such means is to improve diets of the rich by eating lower down the food chain. While most people in the world thrive on mainly grain-based diets, carnivory is high in OECD and is increasing in LDCs. In order to reduce food wastage and to improve health and food availability, a food conversion efficiency tax is proposed. The least efficient converters (pork, beef) would be highly taxed; more efficient converters (poultry, eggs, dairy) would be moderately taxed. Most efficient converters (ocean fish) would be taxed lowest. Grain for human food would not be taxed, while coarse grains might be modestly subsidized. Non-food agriculture also would be taxed: highest on tobacco and on starches destined for alcoholic beverages produced from land suitable for food production.

Introduction

This paper presents the case that diet matters for environmental sustainability. Environmental sustainability means improving our lifestyle in order to maintain natural capital. Keeping natural capital constant means maintaining the two source and sink environmental services unimpaired. Most environmental sustainability will be achieved to the extent the world achieves the transition to renewable energy, and to a stable human population. The most fundamental requirement of environmental sustainability is that capital should remain intact. This requirement must be applied to natural (soils, species, water) as well as to fabricated capital (Goodland, 1995). The paper is addressed to all concerned with accelerating the transition to sustainability in agriculture; its purpose is to sharpen one segment of the sustainability debate. Of all the important changes needed in order to approach environmental sustainability in agriculture, I chose diet for five main reasons.

First, there is no agreement that diet matters for agricultural sustainability, not even that it is a legitimate issue for agricultural policy nor for economic development. Current global trends are hastening in the wrong direction, away from the sustainable course. An increasing number of analysts report that we are moving towards the limits of global food production. Second, diet is a poverty and equity issue. Diet concerns mainly the poor and not the rich. The rich will always be able to buy what diets they want. However, even the rich suffer because their diets are unsustainable. Third, much agriculture is not sustainable, and there is little agreement on what sustainability is applied to the agriculture sector (FAO, 1995, FAO, 1996). Worldwide topsoil loss, salination, waterlogging, depleting aquifers, overgrazing, and agrochemical pollution exemplify lack of sustainability in the agriculture sector. Fourth, the environmental impact of the agriculture sector probably exceeds the impacts of all other sectors, even manufacturing and industry, in many countries. Agriculture has degraded more natural capital and caused more extinctions of species than any other sector. Agriculture uses more water than other sectors of the economy in many nations. Many agricultural practices pollute (e.g. feedlot runoff, abattoirs, effluent from oilpalm, rubber, coffee processing). The energy consumption of agriculture is substantial in industrial countries, considering diesel (tractors, pumps), energy contents of fertilizers and biocides, and transport infrastructure (Cleveland, 1995a; Cleveland, 1995b). Expansion of food supply under any scenario makes the environmental impact of agriculture one of the most urgent and under-addressed predicaments of our times. Fifth, within agriculture, the case to demote cattle on the development, environmental, health and poverty alleviation agendas is strong and intensifying. Cattle caused or are related to the most environmental damage to the globe of any non-human species (e.g. overgrazing, soil erosion, desertification, tropical deforestation for ranches). Cattle biomass probably exceeds human biomass. Cattle numbers have increased 100% over the last 40 years; livestock now outnumber humans 3:1.

These five reasons combine into a compelling argument to promote environmental sustainability in the agriculture sector. Demand-side management, pollution control, loss reduction, and eating more simply will be essential. As a quarter million more people must be fed each day, sustainability must be approached as a matter of great urgency. The powerful ethical argument for promoting environmental sustainability by adjusting diet is left until later.

That diet has become a major opportunity to improve development is becoming recognized (e.g. Nobelist Kendall and Pimentel, 1994Goodland et al., 1984Brown and Kane, 1994Brown et al., 1994Brown, 1995Cohen, 1995Ehrlich et al., 1995Brown et al., 1996). Even so, some people still find these proposals too controversial. Ignoring this opportunity to improve nutrition, reduce poverty, environmental impact and hunger by dietary improvements would be more controversial, uneconomic, and arguably immoral.

We have let the world become so full that there is unfortunately already a trade-off between human numbers and diet. Kendall and Pimentel (1994)estimate that a world population of 7 billion could be supported at current levels of nutrition on a vegetarian diet, assuming ideal distribution and no grain for livestock, but without alleviating current hunger levels. Cohen (1995)writes that ca. 2500 kcal of food are needed for a vegetarian diet, but this figure soars to 9250 kcal if our diet is 30% from animals. This high figure (9250 kcal) means 3.7 times as many edible calories would have to be grown or grazed as are eaten.

Cohen (1995)assumes that 10 kcal of feed are needed for every kcal of energy consumed, then the amount of edible food energy that would have to be grown to supply everybody with 2500 kcal would be 0.7×2,500 (for the vegetable portion of the diet)+0.3×2,500×10 (for the animal portion)=9250 kcal. If people eat some meat, only about 2.5 billion could be provided for; this excludes nearly two out of three people alive today. This is why it is so important for the world to remain low down the food chain, for those high to descend, and to discourage people from moving up.

Section snippets

The global food crisis

There has been no growth in the grain harvest during the first 5 years of the 1990s. Global grain reserves fell to an all-time low in 1995. At the end of 1995, grain carry over reserves dropped to 231 million tons, enough to feed the world for only 48 days. Previously, when reserves fell below 60 days, the price started to rise. In 1995 wheat and maize prices hit 15-year and 12-year highs respectively. The price of corn in China has doubled in the past 3 years; the price of barley has doubled

Extensification

There are only three choices to increase food production; none is encouraging. First is extensification, expansion of cultivated area. There is substantial farmland lying idle, especially where it has been taken out of cultivation by economic policy (e.g. parts of the EU), or because it is uneconomic, or it is fallowing.

There is much scope for raising developing country yields in the direction of OECD yields. Certainly, vastly more agricultural research is essential. Much of this information is

Eating more sustainably

Affluent people in OECD countries consume about 800 kg of grain indirectly (Durning and Brough, 1991), much of it inefficiently converted into animal flesh, with the balance as milk, cheese, eggs, ice cream, and yogurt. Such diets are high in fats and protein, low in starch. In contrast, in low-consuming countries, annual consumption of grains averages 200 kg per person, practically all of it directly, with high efficiencies in conversion. Such diets are rich in starch, low in fats and protein;

Food policy

This paper specifically does not advocate that everyone should adopt grain-based diets immediately. Humans are omnivores, not obligate carnivores. Humans do not need to eat flesh to stay healthy, according to the Nobel biochemist laureate Konrad Bloch (1994), not even infants. Clearly everyone needs to balance their diet, including vegetarians. The amount of protein (plant or animal) that humans need for health is small although not precisely known; 0.8 g/day is on the high side for a healthy

Non-food agriculture

Land allocated to production of products other than food will increasingly be decreased to the extent possible. The tradeoffs between cotton and synthetic fibers need to be environmentally assessed. Land allocated to tobacco production should be taxed higher than for grain-fed beef production. Land allocated to potable alcohol production also would be taxed.

Alcoholic beverages divert much grain; they also should be taxed on conversion efficiency: slightly lower on beer, higher on grain alcohols

The health argument

The fact is that if energy needs are obtained from grain-based diets, then protein requirements will be met. Cereals supply 50% of dietary protein and calories globally, and up to 70% in developing nations (Harris, 1996). As most poor people worldwide are forced to eat grain-based diets and little else, and survive, there should be no argument that eating lower on the food chain risks health. Now even orthodox western health authorities cannot muster arguments strong enough to satisfy meat

Conclusion

Diet is one of the measures needed to approach environmental sustainability in the agricultural sector. Improving diets by eating low on the food chain, eating much less or no meat and more grains, would vastly improve food production efficiency, decrease environmental impact, and reduce waste. Improving diet also improves health. Vegan infants and children are better off than their carnivorous colleagues. These are compelling arguments to eat low down the food chain.

The only reasons to eat

Acknowledgements

Warm appreciation is offered for all the generous comments on earlier drafts and support received from Lester Brown, Cutler Cleveland, John Cobb, Herman Daly, Jeff McNeely, David Pimentel, Jan Post, Salah El Serafy, G. Tillman, Tom Regan, T. and J. Whitten.

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