Discussion

. Steve Mcsweeny/iStock/Thinkstock

Learning Objectives

After studying this chapter, you should be able to:

• Discuss how a growing population combined with changing diets is putting increased pressure on world food supplies.

• Describe how modern or conventional agricultural approaches lead to environmental impacts on soil fertility, water quality, air quality, and wildlife habitat.

• Explain the basic principle behind genetic engineering of crops and discuss the environmental and health debates surrounding the development and expanded use of biotechnology.

• Discuss the state of the world’s fisheries and describe how an indicator known as the seafood print can be used to measure the impact of different nations on global fish stocks.

• Discuss the difference in environmental and social impact between foods grown locally and those shipped over long distances.

Feeding the World 3

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IntroDuctIon

Pre-Test

1. the poorest people on the planet spend from _______ to ________ percent of their income on food.

a. 10 to 20 b. 20 to 30 c. 30 to 50 d. 50 to 70 2. Which of the following is not an attribute that has an important impact on soil quality? a. texture b. Depth c. color d. Permeability 3. A situation in which weeds evolve so that chemical sprays are no longer effective in

controlling them is known as a. pesticide resistance. b. herbicide resistance. c. nutrient management. d. chemical resistance. 4. A measure developed by marine biologists to estimate the amount of primary

production required to make a pound of different kinds of fish is known as a. the ecological footprint. b. the seafood print. c. the marine food web. d. sustainable production. 5. Which of the following is a method that promotes nutrient recycling? a. Having mega-sized livestock b. Having a chicken farm c. Having a mixed crop-livestock operation d. Having a corn and grain farm

Answers 1. d. 50 to 70. the answer can be found in section 3.1. 2. c. color. the answer can be found in section 3.2. 3. b. herbicide resistance. the answer can be found in section 3.3. 4. b. the seafood print. the answer can be found in section 3.4. 5. c. Having a mixed crop-livestock operation. the answer can be found in section 3.5.

Introduction Severe droughts in china and russia, floods in Australia, and a deep freeze in Mexico reduced global crop yields in 2010 and caused food prices to increase across the world. Between July 2010 and January 2011, the global price of wheat increased by 66.8 percent, from $190 per metric ton to $327 per metric ton (Index Mundi, 2011). the price of many other food com- modities went up by similar amounts so that in January 2011, the Global Food Price Index reached its highest level ever. While most of the wealthier people in the world could afford an extra 25 or 50 cents for a loaf of bread, in developing countries, rising food prices pushed 44 million more people into extreme poverty during this time period.

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now that the human population has surpassed seven billion and continues to grow at the rate of roughly 80 million every year, agricultural experts are asking whether the world can con- tinue to produce enough food for everyone. Along with total growth, people in many devel- oping countries such as china and India are becoming wealthier and are eating a richer diet, including more meat, which requires more cropland to produce.

the problem is that conventional approaches to agriculture lead to a number of serious envi- ronmental impacts. Attempts to feed a growing human population will, if we continue to use the same techniques, only worsen those impacts. consider the following:

• Agriculture in the united States accounts for over 80 percent of all freshwater use and as much as 90 percent in some western states (http://www.ers.usda.gov /topics/farm-practices-management/irrigation-water-use.aspx#.uitvhJu_Yrk).

• runoff of pesticides and other chemicals from agricultural fields is a major source of water pollution (http://www.fws.gov/contaminants/Issues/Pesticides.cfm).

• Agriculture accounts for roughly 17 percent of all energy use in the united States and is therefore a major contributor to global climate change (http://epa.gov /climatechange/ghgemissions/sources/agriculture.html).

• Large-scale meat production in what are known as concentrated animal feeding operations (cAFos) requires large doses of antibiotics to control disease and has been linked to the development of antibiotic-resistant bacteria (http://www.ncifap .org/_images/212-2_Antbiorprt_FIn_web%206.7.10%202.pdf).

these are just a handful of some of the environmental impacts from agriculture that will be covered in this chapter. they suggest that a business-as-usual approach to feeding the world is not sustainable. Alternative approaches that increase yields while balancing environmen- tal, human health, and wildlife concerns will be needed. As these readings will demonstrate, the answers to how we can do this vary from group to group, and they are the source of much political and scientific debate. We start with a review of the sheer challenge involved in feed- ing a world of nine billion or more. the second section documents the environmental impacts of conventional approaches to agriculture. Section 3.3 introduces what is perhaps one of the most controversial subjects in environmental science today—the issue of biotechnology and genetically modified (GM) crops. We’ll see that the GM debate is highly polarized with each side accusing the other of practicing “junk science” and spreading lies to advance their argu- ments. Section 3.4 takes a look at the state of the world’s fisheries and how population growth and destructive fishing practices are threatening this resource. the chapter concludes on a more hopeful note with a discussion of efforts to produce more food locally and sustainably.

3.1 The Global Food Crisis—Feeding Nine Billion By the 1960s, rising populations and stagnant world grain production combined to create the specter of massive famine. In response, scientists and development organizations launched what came to be known as the green revolution. This revolution involved the development of new varieties of wheat, rice, and other grains that doubled yields and allowed farmers in tropical regions to grow two crops a year instead of just one. The results were staggering: famine was largely avoided in certain regions of the world and green revolution grain varieties came to dominate farming in many regions of the world.

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However, in order to grow green revolution varieties, farmers were required to use much larger quantities of irrigated water, fertilizers for plant growth, and pesticides and herbicides to con- trol insect pests and weeds. These varieties also did better when they were planted in large blocks of a single variety, known as monocultures. This, in turn, necessitated the use of even more irrigated water, fertilizers, pesticides, and herbicides. Today, crop yields from green revo- lution varieties have peaked and are no longer responding the way they once did to increased applications of fertilizer and other inputs. Furthermore, over-pumping of groundwater for irri- gation and over-use of synthetic fertilizers, pesticides, and herbicides are taking an increasing environmental toll.

In the following article, Joel K. Bourne, Jr., of national Geographic Magazine reviews the history of the first green revolution and explains why it might be time for another one. With crop yields stagnant and the population still growing (though at a slower rate than 50 years ago)—and increasing affluence in countries like China and India spurring increased food consumption— Bourne argues that we could be on the verge of a global food crisis, especially for the world’s poorest. The question is whether the next revolution in agriculture will focus on high-tech approaches such as genetic engineering or on new ways of farming in a less environmentally destructive manner sometimes referred to as agroecology or sustainable agriculture, or both. This question will be the subject of further discussion in the sections to come.

By Joel K. Bourne, Jr. It is the simplest, most natural of acts, akin to breathing and walking upright. We sit down at the dinner table, pick up a fork, and take a juicy bite, oblivious to the double helping of global ramifications on our plate. our beef comes from Iowa, fed by nebraska corn. our grapes come from chile, our bananas from Honduras, our olive oil from Sicily, our apple juice—not from Washington State but all the way from china. Modern society has relieved us of the burden of growing, harvesting, even preparing our daily bread, in exchange for the burden of simply paying for it. only when prices rise do we take notice. And the consequences of our inatten- tion are profound.

Last year [2007] the skyrocketing cost of food was a wake-up call for the planet. Between 2005 and the summer of 2008, the price of wheat and corn tripled, and the price of rice climbed fivefold, spurring food riots in nearly two dozen countries and pushing 75 million more people into poverty. But unlike previous shocks driven by short-term food shortages, this price spike came in a year when the world’s farmers reaped a record grain crop. this time, the high prices were a symptom of a larger problem tugging at the strands of our world- wide food web, one that’s not going away anytime soon. Simply put: For most of the past decade, the world has been consuming more food than it has been producing. After years of drawing down stockpiles, in 2007 the world saw global carryover stocks fall to 61 days of global consumption, the second lowest on record.

“Agricultural productivity growth is only one to two percent a year,” warned Joachim von Braun, director general of the International Food Policy research Institute in Washington, D.c., at the height of the crisis. “this is too low to meet population growth and increased demand.”

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High prices are the ultimate signal that demand is outstripping supply, that there is simply not enough food to go around. Such agflation hits the poorest billion people on the planet the hardest, since they typically spend 50 to 70 percent of their income on food. Even though prices have fallen with the imploding world economy, they are still near record highs, and the underlying problems of low stockpiles, rising population, and flattening yield growth remain. climate change—with its hotter growing seasons and increasing water scarcity—is projected to reduce future harvests in much of the world, raising the specter of what some scientists are now calling a perpetual food crisis.

So What Is a Hot, Crowded, and Hungry World to Do? that’s the question von Braun and his colleagues at the consultative Group on International Agricultural research are wrestling with right now. this is the group of world-renowned agri- cultural research centers that helped more than double the world’s average yields of corn, rice, and wheat between the mid-1950s and the mid-1990s, an achievement so staggering it was dubbed the green revolution. Yet with world population spiraling toward nine billion by mid-century, these experts now say we need a repeat performance, doubling current food production by 2030.

In other words, we need another green revolution. And we need it in half the time. [. . .]

The High Cost of Meat It’s no coincidence that as countries like china and India prosper and their people move up the food ladder, demand for grain has increased. For as tasty as that sweet-and-sour pork may be, eating meat is an incredibly inefficient way to feed oneself. It takes up to five times more grain to get the equivalent amount of calories from eating pork as from simply eating grain itself—ten times if we’re talking about grain-fattened u.S. beef. As more grain has been diverted to livestock and to the production of biofuels for cars, annual worldwide consump- tion of grain has risen from 815 million metric tons in 1960 to 2.16 billion in 2008. Since

2005, the mad rush to biofuels alone has pushed grain-consumption growth from about 20 million tons annually to 50 mil- lion tons, according to Lester Brown of the Earth Policy Institute.

Even china, the second largest corn- growing nation on the planet, can’t grow enough grain to feed all its pigs. Most of the shortfall is made up with imported soybeans from the u.S. or Brazil, one of the few countries with the potential to expand its cropland—often by plowing

up rain forest. Increasing demand for food, feed, and biofuels has been a major driver of defor- estation in the tropics. Between 1980 and 2000 more than half of new cropland acreage in the tropics was carved out of intact rain forests; Brazil alone increased its soybean acreage in Amazonia 10 percent a year from 1990 to 2005.

Consider This using your understanding of trophic lev- els from chapter 1, why does it take five to ten times more grain to get the equivalent amount of calories from pork or beef com- pared to simply eating the grain itself ?

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Some of those Brazilian soybeans may end up in the troughs of Guangzhou Lizhi Farms, the largest cAFo [con- centrated animal feeding operation] in Guangdong Province. tucked into a green valley just off a four-lane high- way that’s still being built, some 60 white hog houses are scattered around large ponds, part of the waste-treat- ment system for 100,000 hogs. the city of Guangzhou is also building a brand-new meatpacking plant that will slaughter 5,000 head a day. By the time china has 1.5 billion people, sometime in the next 20 years, some experts predict they’ll need another 200 mil- lion hogs just to keep up. And that’s just china. World meat consumption is expected to double by 2050. that means we’re going to need a whole lot more grain.

The First Green Revolution this isn’t the first time the world has stood at the brink of a food crisis—it’s only the most recent iteration. At 83, Gurcharan Singh Kalkat has lived long enough to remember one of the worst famines of the 20th century. In 1943 as many as four million people died in the “Malthusian correction” known as the Bengal Famine. For the following two decades, India had to import millions of tons of grain to feed its people.

then came the green revolution. In the mid-1960s, as India was struggling to feed its people during yet another crippling drought, an American plant breeder named norman Borlaug was working with Indian researchers to bring his high-yielding wheat varieties to Punjab. the new seeds were a godsend, says Kalkat, who was deputy director of agriculture for Punjab at the time. By 1970, farmers had nearly tripled their production with the same amount of work. “We had a big problem with what to do with the surplus,” says Kalkat. “We closed schools one month early to store the wheat crop in the buildings.”

Borlaug was born in Iowa and saw his mission as spreading the high-yield farming methods that had turned the American Midwest into the world’s breadbasket to impoverished places throughout the world. His new dwarf wheat varieties, with their short, stocky stems support- ing full, fat seed heads, were a startling breakthrough. they could produce grain like no other wheat ever seen—as long as there was plenty of water and synthetic fertilizer and little com- petition from weeds or insects. to that end, the Indian government subsidized canals, fertilizer, and the drilling of tube wells for irrigation and gave farmers free electricity to pump the water. the new wheat varieties quickly spread throughout Asia, changing the traditional farming practices of millions of farmers, and were soon followed by new strains of “miracle” rice. the new crops matured faster and enabled farmers to grow two crops a year instead of one. today a double crop of wheat, rice, or cotton is the norm in Punjab, which, with neighboring Haryana, recently supplied more than 90 percent of the wheat needed by grain-deficient states in India.

Imaginechina via AP Images

High demand for meat means a higher need for grain to feed livestock. The soybeans used to feed these Chinese-produced pigs is imported from Brazil and the United States because China does not produce enough grain to feed all its livestock.

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the green revolution Borlaug started had nothing to do with the eco-friendly green label in vogue today. With its use of synthetic fertilizers and pesticides to nurture vast fields of the same crop, a practice known as monoculture, this new method of industrial farming was the antithesis of today’s organic trend. rather, William S. Gaud, then admin- istrator of the u.S. Agency for Interna- tional Development, coined the phrase in 1968 to describe an alternative to russia’s red revolution, in which work- ers, soldiers, and hungry peasants had rebelled violently against the tsarist government. the more pacifying green revolution was such a staggering suc- cess that Borlaug won the nobel Peace Prize in 1970.

today, though, the miracle of the green revolution is over in Punjab: Yield growth has essentially flattened since

the mid-1990s. overirrigation has led to steep drops in the water table, now tapped by 1.3 mil- lion tube wells, while thousands of hectares of productive land have been lost to salinization [soils becoming salty] and waterlogged soils. Forty years of intensive irrigation, fertilization, and pesticides have not been kind to the loamy gray fields of Punjab. nor, in some cases, to the people themselves. [. . .]

“the green revolution has brought us only downfall,” says Jarnail Singh, a retired school- teacher in Jajjal village. “It ruined our soil, our environment, our water table. used to be we had fairs in villages where people would come together and have fun. now we gather in medi- cal centers. the government has sacrificed the people of Punjab for grain.”

others, of course, see it differently. rattan Lal, a noted soil scientist at ohio State who gradu- ated from Punjab Agricultural university in 1963, believes it was the abuse—not the use—of green revolution technologies that caused most of the problems. that includes the overuse of fertilizers, pesticides, and irrigation and the removal of all crop residues from the fields, essentially strip-mining soil nutri- ents. “I realize the problems of water quality and water withdrawal,” says Lal. “But it saved hundreds of millions of people. We paid a price in water, but the choice was to let people die.”

In terms of production, the benefits of the green revolution are hard to deny. India hasn’t experienced famine since Borlaug brought his seeds to town, while world grain production has more than doubled.

Consider This During the mid-1960s, rising global popu- lations, stagnant grain production, and specific crises such as the Bengal Famine prompted agricultural science to launch the green revolution. Describe the benefits and drawbacks of the green revolution, particularly as seen in India.

AP Photo

While it eased hunger, the green revolution also created a number of other problems, including the overuse of fertilizers, pesticides, and irrigation that depleted nutrients from the soil. Here, an Indian man stands in a “bumper crop” of wheat during the green revolution.

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Some scientists credit increased rice yields alone with the existence of 700 million more peo- ple on the planet.

The Next Green Revolution Many crop scientists and farmers believe the solution to our current food crisis lies in a sec- ond green revolution, based largely on our newfound knowledge of the gene. Plant breeders now know the sequence of nearly all of the 50,000 or so genes in corn and soybean plants and are using that knowledge in ways that were unimaginable only four or five years ago, says robert Fraley, chief technology officer for the agricultural giant Monsanto. Fraley is con- vinced that genetic modification, which allows breeders to bolster crops with beneficial traits from other species, will lead to new varieties with higher yields, reduced fertilizer needs, and drought tolerance—the holy grail for the past decade. He believes biotech will make it pos- sible to double yields of Monsanto’s core crops of corn, cotton, and soybeans by 2030. “We’re now poised to see probably the greatest period of fundamental scientific advance in the his- tory of agriculture.” [. . .]

But is a reprise of the green revolution—with the traditional package of synthetic fertilizers, pesticides, and irrigation, supercharged by genetically engineered seeds—really the answer to the world’s food crisis? Last year a massive study called the “International Assessment of Agricultural Knowledge, Science and technology for Development” concluded that the immense production increases brought about by science and technology in the past 30 years have failed to improve food access for many of the world’s poor. the six-year study, initiated by the World Bank and the un’s Food and Agriculture organization and involving some 400 agricultural experts from around the globe, called for a paradigm shift in agriculture toward more sustainable and ecologically friendly practices that would benefit the world’s 900 mil- lion small farmers, not just agribusiness.

the green revolution’s legacy of tainted soil and depleted aquifers is one reason to look for new strategies. So is what author and university of california, Berkeley, professor Michael Pollan calls the Achilles heel of current green revolution methods: a dependence on fossil fuels. natural gas, for example, is a raw material for nitrogen fertilizers. “the only way you can have one farmer feed 140 Americans is with monocultures. And monocultures need lots of fossil-fuel-based fertilizers and lots of fossil-fuel-based pesticides,” Pollan says. “that only works in an era of cheap fossil fuels, and that era is coming to an end. Moving anyone to a dependence on fossil fuels seems the height of irresponsibility.”

So far, genetic breakthroughs that would free green revolution crops from their heavy depen- dence on irrigation and fertilizer have proved elusive. Engineering plants that can fix their own nitrogen or are resistant to drought “has proven a lot harder than they thought,” says Pollan. Monsanto’s Fraley predicts his company will have drought-tolerant corn in the u.S. market by 2012. But the increased yields promised during drought years are only 6 to 10 percent above those of standard drought-hammered crops.[*]

* notE: Monsanto has, in fact, received clearance from the u.S. Department of Agriculture (uSDA) to market its drought-tolerant corn in the united States. However, early trials of the crop were not very successful and it remains to be seen whether it will be adopted to any significant degree by farmers (http://e360.yale.edu/digest /drought-resistant_gm_corn_poses_limited_risk_-_or_benefit_us_says/2941/).

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A Change in Focus—Agroecology And so a shift has already begun to small, underfunded projects scattered across Africa and Asia. Some call it agroecology, others sustainable agriculture, but the underlying idea is revo- lutionary: that we must stop focusing on simply maximizing grain yields at any cost and con- sider the environmental and social impacts of food production. Vandana Shiva is a nuclear physicist turned agroecologist who is India’s harshest critic of the green revolution. “I call it monocultures of the mind,” she says. “they just look at yields of wheat and rice, but overall the food basket is going down. there were 250 kinds of crops in Punjab before the green revolution.” Shiva argues that small-scale, biologically diverse farms can produce more food with fewer petroleum-based inputs. Her research has shown that using compost instead of natural-gas-derived fertilizer increases organic matter in the soil, sequestering carbon and holding moisture—two key advantages for farmers facing climate change. “If you are talking about solving the food crisis, these are the methods you need,” adds Shiva.

In northern Malawi one project is getting many of the same results as the Millennium Villages project, at a fraction of the cost. there are no hybrid corn seeds, free fertilizers, or new roads here in the village of Ekwendeni. Instead the Soils, Food and Healthy communities (SFHc) project distributes legume seeds, recipes, and technical advice for growing nutritious crops like peanuts, pigeon peas, and soybeans, which enrich the soil by fixing nitrogen while also enriching children’s diets. the program began in 2000 at Ekwendeni Hospital, where the staff was seeing high rates of malnutrition. research suggested the culprit was the corn monocul- ture that had left small farmers with poor yields due to depleted soils and the high price of fertilizer. [. . .]

Which is why the project’s research coordinator, rachel Bezner Kerr, is alarmed that big- money foundations are pushing for a new green revolution in Africa. “I find it deeply dis- turbing,” she says. “It’s getting farmers to rely on expensive inputs produced from afar that are making money for big companies rather than on agroecological methods for using local resources and skills. I don’t think that’s the solution.”

The Challenge Ahead regardless of which model prevails—agriculture as a diverse ecological art, as a high-tech industry, or some combination of the two—the challenge of putting enough food in nine bil- lion mouths by 2050 is daunting. two billion people already live in the driest parts of the globe, and climate change is projected to slash yields in these regions even further. no mat- ter how great their yield potential, plants still need water to grow. And in the not too distant future, every year could be a drought year for much of the globe.

new climate studies show that extreme heat waves, such as the one that withered crops and killed thousands in western Europe in 2003, are very likely to become common in the tropics and subtropics by century’s end. Himalayan glaciers that now provide water for hundreds of millions of people, livestock, and farmland in china and India are melting faster and could vanish completely by 2035. In the worst-case scenario, yields for some grains could decline by 10 to 15 percent in South Asia by 2030. Projections for southern Africa are even more dire. In a region already racked by water scarcity and food insecurity, the all-important corn harvest could drop by 30 percent—47 percent in the worst-case scenario. All the while the

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population clock keeps ticking, with a net of 2.5 more mouths to feed born every second. that amounts to 4,500 more mouths in the time it takes you to read this article. [. . .]

Adapted from Bourne, J. K., Jr. (2009). The Global Food Crisis: The End of Plenty. national Geographic Magazine. Retrieved from http://ngm.nationalgeographic.com/print/2009/06/cheap-food/bourne-text. Joel K. Bourne/ National Geographic Creative. Used by permission.

Apply Your Knowledge on average, Americans consume approximately 270 pounds of meat per person per year, among the highest rates of consumption in the world and often 20 times as much as people in some poorer countries. As made clear in this reading, a meat-based diet requires significant grain production as well as massive inputs of energy and water. review the chart found on this web page (http://www.npr.org/blogs/thesalt/2012/06/27/155527365/visualizing-a -nation-of-meat-eaters) to get a sense of how much grain, water, land, and fossil fuel energy is required to make one quarter-pound hamburger. next, estimate how many hamburgers you eat per year (if you don’t eat meat or burgers, then do this calculation for someone you know who does). Based on that estimate and the figures provided on the web page, calculate how much grain, water, land, and energy is required to make this level of hamburger con- sumption possible.

3.2 Environmental Impacts of Conventional Agriculture Our modern or conventional agricultural system produces a staggering amount of food at rela- tively low costs to consumers. Americans spend as little as 7 percent of their income on food, over half of what we spent a generation ago and far less than what people in other countries spend to feed themselves. Despite this success, there are concerns that conventional approaches to agriculture—which emphasize heavy inputs of energy, water, and synthetic fertilizers and pesticides—could impose environmental and health costs on society that are not reflected in the prices we pay for food. This briefing by staff of the U.S. Department of Agriculture Economic Research Service reviews some of the major environmental issues associated with conventional agricultural production.

The following report highlights some of the key areas of concern when assessing the environ- mental impacts of agriculture, which include soil erosion, water pollution, air pollution, and habitat destruction. Modern agricultural techniques involve extensive plowing and manipula- tion of soils, and this can result in soil erosion by wind and rain. Eroded soils can reduce farmland fertility, pollute local waterways, and carry fertilizers and pesticides into surface waters. When nitrogen and phosphorous from agricultural fertilizers or animal manure wash into rivers and other bodies of water, they can promote the growth of algae, a process known as eutrophica- tion. This can lead to decreased oxygen levels in the water and the death of many fish and other aquatic organisms. Pesticide runoff, pesticides leaching into groundwater, and pesticide residues on food crops and fruit can also pose health concerns. Agriculture also results in air pollution from a number of sources, including particulate matter from wind erosion and smog formation from agricultural chemicals and emissions of pollutants from farm equipment. Lastly, agricul- ture often involves the conversion of natural habitats to human uses, and this can have negative impacts on wildlife and biodiversity (as will be discussed in Chapter 4). Given the seriousness of

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these impacts it’s clear why the debate over biotechnology and genetic engineering (section 3.3) takes on such importance. Advocates of this approach argue that it will help address many of agriculture’s environmental impacts, but critics argue that it might, in fact, make things worse.

By Staff of the U.S. Department of Agriculture Economic Research Service over 440 million acres (19.5 percent of land) is dedicated to growing crops in the u.S., and another 587 million acres (26 percent) is in pasture and range, largely used for domestic live- stock production. Agricultural activities on these lands produce a plentiful, diverse, and rela- tively inexpensive supply of food and fiber for people here at home and abroad. However, agri- cultural production practices can degrade the environment. transformation of undisturbed land to crop production can diminish habitat for wildlife. Soil erosion, nutrient and pesticide runoff, and irrigation can pollute the air and water, degrade soil quality, and diminish water supplies. the extent and degree of the environmental problems associated with agriculture vary widely across the country. concern over these problems has given rise to local, State, and Federal conservation and environmental policies and programs to address them.

Soil Quality Soil, as a plant-growing medium, is the key resource in crop production. Soil supports the fundamental physical, chemical, and biological processes that must take place in order for plants to grow [. . .]. Soil can also function as a “degrader” or “immobilizer” [the ability to break down or hold in place pollutants so that they do not enter groundwater supplies] of agricultural chemicals, wastes, or other potential pollutants, and can mitigate climate change by sequestering [absorbing] carbon from the atmosphere [. . .]. How well soil performs these functions depends on soil quality. How soil is managed has a major impact on soil quality, and on the potential for various pollutants to leave the field and affect other resources.

Soil quality can be defined as the capacity of a specific kind of soil to function, within natu- ral or managed ecosystem boundaries, to sustain plant and animal productivity, maintain or enhance water and air quality, and support human health and habitation. Soil quality depends on attributes such as the soil’s texture, depth, permeability, biological activity, capacity to store water and nutrients, and organic matter content. Soil quality can be maintained or enhanced through the use of appropriate crop production technologies and related resource management systems. Poorly managed fields can lead to soil degradation through three pro- cesses: physical degradation, such as via wind and water erosion and soil compaction; chemi- cal degradation, such as toxification [conversion of chemicals into toxic forms], acidification, and salinization; and biological degradation, such as loss of organic matter and decline in the activity of soil fauna. Poor management can also increase runoff of nutrients and pesticides to surface and groundwater systems. thus, soil degradation can have both direct and indirect negative effects on agricultural productivity and the environment. Even on high-quality soils, overuse of chemical inputs can result in soil toxicity and water pollution.

Water Quality Agriculture is widely believed to have significant impacts on water quality. While no compre- hensive national study of agriculture and water quality has been conducted, the magnitude of the impacts can be inferred from several water quality assessments. A general assessment of water quality is provided by EPA’s 2002 Water Quality Inventory. Based on State assessments of 19 percent of river and stream miles, 37 percent of lake acres, and 35 percent of estuarine

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square miles, EPA concluded that agriculture is the leading source of pollution in 37 percent of river miles, 30 percent of lake acres (excluding the Great Lakes), and 8 percent of estuarine waters found to be water-quality impaired, in that they do not support designated uses. this makes agriculture the leading source of impairment in the nation’s rivers and lakes, and a minor source of impairment in estuaries. Agriculture’s contribution has remained relatively unchanged over the past decade.

Major Agricultural Pollutants Sediment [naturally occurring material that can wash off of fields] is the largest contami- nant of surface water by weight and volume, and is identified by States as the leading pol- lution problem in rivers and streams and the fourth leading problem in lakes. Sediment in surface water is largely a result of soil erosion, which is influenced by soil properties and the production practices farmers choose. Sediment buildup reduces the useful life of reser- voirs. Sediment can clog roadside ditches and irrigation canals, block navigation channels, and increase dredging costs. By raising streambeds and burying streamside wetlands, sedi- ment increases the probability and severity of floods. Suspended sediment can increase the cost of water treatment for municipal and industrial water uses. Sediment can also destroy or degrade aquatic wildlife habitat, reducing diversity and damaging commercial and recre- ational fisheries.

nitrogen and phosphorus [two critical plant nutrients] are important crop nutrients, and farmers apply large amounts to cropland each year. they can enter water resources through runoff and leaching [percolate through the ground]. the major concern for surface-water quality is the promotion of algae growth (known as eutrophication), which can result in decreased oxygen levels, fish kills, clogged pipelines, and reduced recreational opportunities. the u.S. Geological Survey (uSGS) has found that high concentrations of nitrogen in agricul- tural streams are correlated with nitrogen inputs from fertilizers and manure used on crops and from livestock waste. EPA reported in its Water Quality Inventory that nutrient pollution is the leading cause of water quality impairment in lakes, and a major cause of oxygen deple- tion in estuaries. [. . .]

Eutrophication and hypoxia (low oxygen levels) in the northern Gulf of Mexico have been linked to nitrogen loadings from the Mississippi river. Agricultural sources (fertilizer, soil inorganic nitro- gen, and manure) are estimated to con- tribute about 71 percent of the nitrogen loads entering the Gulf from the Mis- sissippi Basin, and 80 percent of phos- phorus loads. the Gulf of Mexico is not the only coastal area affected by nutri- ents. recent research by the national oceanographic and Atmospheric Admin- istrations has found that 65 percent of assessed estuaries had moderate to high overall eutrophic conditions, caused pri- marily by nitrogen enrichment.

Consider This nitrogen and phosphorous are fertilizers, and when they enter water bodies like lakes and streams, they promote the growth of aquatic plants and algae. Why is this a prob- lem? Design an experiment, using the basic principles of the scientific method, to test how additions of different amounts of nitro- gen and phosphorous might affect water quality and wildlife in a body of water.

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Farmers apply a wide variety of pesticides to control insects (insecticides), weeds (herbi- cides), fungus (fungicides), and other problems. Well over 500 million pounds (active ingredi- ent) of pesticides have been applied annually on farmland since the 1980s, and certain chemi- cals can travel far from where they are applied. Pesticide residues reaching surface-water systems may harm freshwater and marine organisms, damaging recreational and commercial fisheries. Pesticides in drinking water supplies may also pose risks to human health. Pesticide concentrations exceeded one or more human-health benchmarks in about 10 percent of agri- cultural streams examined by uSGS as part of the national Water Quality Assessment Pro- gram, and in about 1 percent of sampled wells used for drinking water in agricultural areas.

Some irrigation water applied to crop- land may run off the field into ditches and receiving waters. these irrigation return flows often carry dissolved salts as well as nutrients and pesti- cides into surface or ground water. Increased salinity levels in irrigation water can reduce crop yields or dam- age soils such that some crops can no longer be grown. Increased concen- trations of naturally occurring toxic minerals—such as selenium, molyb- denum, and boron—can harm aquatic wildlife and impair water-based rec- reation. Increased levels of dissolved solids in public drinking water supplies can increase water treatment costs, force the development of alternative water supplies, and reduce the lifes- pans of water-using household appli- ances. the possibility of pathogens contaminating water supplies and rec- reation waters is a continuing concern. Bacteria are the largest source of impairment in rivers and streams, according to EPA’s water quality inventory. Potential sources include inadequately treated human waste, wildlife, unconfined livestock, and animal operations. Diseases from micro-organisms in livestock waste can be contracted through direct contact with contami- nated water, consumption of contaminated drinking water, consumption of crops irrigated with contaminated water, or consumption of contaminated shellfish. [. . .]

Air Quality Ever since farmers began raising animals and cultivating crops, agricultural production prac- tices have generated a variety of substances that enter the atmosphere with the potential of creating health and environmental problems. the relationship between agriculture and air quality became a national issue in the 1930s with the severe dust storms of the Dust Bowl. Although dust storms of this magnitude no longer occur in the united States, soil particulates, farm chemicals, and odor from livestock are still carried in the air we breathe. these emis- sions can harm human health and pollute the environment. Air quality in most rural areas is not a cause for concern, but there are some farming communities where ozone and particu- lates have impaired air quality to the same extent as in urban areas.

Jan Sochor/age fotostock/SuperStock

A farmer wearing a full-body protective suit sprays crops with pesticides. The level of protection is warranted; many pesticides are known carcinogens, teratogens, and endocrine disruptors for animals and humans.

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Ammonia is a gas and one of the most abundant nitrogen-containing compounds emitted to the atmosphere. Animal farming systems contribute about 50 percent of the total anthropo- genic [man-made] emissions of ammonia into the atmosphere in the u.S. Ammonia is a health hazard to humans and animals in high concentrations. once in the atmosphere, ammonia is rapidly converted to ammonium particles by reactions with acidic compounds such as nitric acid and sulfuric acid found in ambient aerosols [small, airborne particles]. these ammonium particles can be carried long distances in the atmosphere and contribute to fine particulate pollution and haze. Ammonium is redeposited to the earth’s surface by both wet and dry deposition [the process by which particles deposit to the ground; wet refers to rain and dry usually to gravity] contributing to eutrophication of water resources.

nitrous oxide is another nitrogen compound of concern. It is a greenhouse gas and contrib- utes to ozone depletion. nitrous oxide forms primarily in the soil during the microbial pro- cesses of nitrification [conversion of ammonia to nitrite] and denitrification [conversion of nitrate to nitrogen]. Agricultural sources include manure from livestock farming and com- mercial fertilizer. Agriculture contributes about 72 percent of total anthropogenic emissions of nitrous oxide in the u.S., mostly from the fertilization of cropland.

Methane is an important greenhouse gas. It is produced by microbial degradation of organic matter under anaerobic conditions. the agricultural sector is the largest anthropogenic source, with livestock production being the major component. Enteric fermentation (within the stomachs of cattle, sheep, goats and other ruminants) and manure management contrib- ute 27 percent of methane emissions in the united States.

carbon dioxide is the primary greenhouse gas emitted in the u.S., mostly from the combustion of fossil fuels. carbon dioxide is also a primary input in plant growth. Agriculture can seques- ter [store] carbon in soils and biomass, thus offsetting greenhouse gas emissions. carbon entering the soil is stored primarily as soil organic matter. Agricultural soils sequestered an estimated 12.4 million metric tons carbon equivalent in 2004, less than 1 percent of u.S. emis- sions. Studies indicate that it may be technically possible to sequester an additional 89–318 million metric tons of carbon annually on u.S. croplands and grazing lands through various management practices, such as conservation tillage, crop rotations, and fertilizer manage- ment. Shifting cropland to grasslands or forest could increase sequestration even more.

Particulates from agriculture result from a variety of activities. Wind erosion can carry soil particles directly into the atmosphere. Many areas west of the Mississippi river experience low average rainfall, frequent drought, and relatively high wind velocities. these conditions, when combined with fine soils, sparse vegetative cover, and agricultural activity, make some western regions susceptible to wind erosion.

Wind erosion can produce short-term levels of particulate pollution in rural areas that exceed urban levels. Particulates from wind erosion can impose costs on those living in affected areas, including cleaning and maintenance of businesses and households, damage to nonfarm machinery, and adverse effects on health. Another source of particulates is open-field burn- ing. open-field burning is used as a means of removing crop residue after harvest and control- ling disease, weeds, and pests. Diesel engines from farm equipment and irrigation pumps are also a source of particulates.

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SEctIon 3.2 EnVIronMEntAL IMPActS oF conVEntIonAL AGrIcuLturE

A source of fine particulates (particles smaller than 2.5 microns, also known as PM2.5) is gas- eous emissions of ammonia and nitrogen oxides (nox, or nitric oxide, and nitrogen dioxide). Ammonia and nox in the atmosphere react with other compounds to form fine particulates, such as ammonium. Fine particulates pose a health risk because they can be inhaled deep into lungs. Fine particulates are also a source of haze, which detracts from views in many popular national parks.

the atmosphere is now recognized as a major pathway by which pesticides can be trans- ported and deposited far from their point of use. Pesticides can enter the atmosphere directly from the spray cloud during application, from evaporation after application, and attached to windborne soil particles. As much as 80 percent of some pesticide applications evapo- rate. And many of these pesticides across different chemical groups have been detected in the atmosphere. the u.S. Geological Survey found that the most frequently detected pesticides in the atmosphere are DDt, methidathion, diazinon, heptachlor, malathion, and dieldrin. Even though some of these have been banned for years, they continue to be detected. [. . .]

Wildlife Habitat Habitat is a combination of environmental factors that provides the food, water, cover, and space that a living organism needs to survive and reproduce. Agricultural land use can benefit some species, harm others, and sometimes do both. Potentially harmful effects of farming include plowing up habitat, farming riparian [along the banks of a river or stream] buffers, fragmenting habitat, diverting water for irrigation, and diffusing agricultural chemicals into the environment. In addition, specialization in agriculture reduces landscape diversity by cre- ating more of a monoculture [growing only one crop]. this reduces the presence of ecological niches, which can limit wildlife populations and biodiversity on farms. Historically, the con- version of native forests, prairies, and wetlands to cropland has diminished wildlife. Habitat loss associated with agricultural practices on over 400 million acres of cropland has been identified as a primary factor depressing wildlife populations in north America. Agriculture is thought to affect the survival of 380 of the 663 species listed by the Federal Government as threatened or endangered in the conterminous 48 States.

Agriculture’s negative effects on wildlife need not be permanent. u.S. agriculture is in a unique position with respect to the nation’s wildlife resources. the management of land now con- trolled by u.S. farms and ranches can play a major role in protecting and enhancing the nation’s wildlife. In 2002, private farms accounted for 41 percent of all u.S. land, including 434 million acres of cropland and 395 million acres of pasture and range. Farms also account for 76 mil- lion acres of forest and woodland, and 17 million acres of nonfederal wetlands. Different types of habitat can be restored or improved through conservation on agricultural lands.

Grassland Habitat Grasslands constitute the largest land cover on America’s private lands. Privately owned grass- lands and shrub lands (including tribal) cover more than 395 million acres in the united States. these lands contribute significantly to the economies of many regions, provide biodiversity of

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plant and animal populations, and play a key role in environmental quality. Grasslands directly support the live- stock industry. they also provide habi- tat for many wildlife species, reduce the potential for flooding, control sedi- ment loadings in streams and other water bodies, and provide ecological benefits such as nutrient cycling, stor- age of atmospheric carbon, and water conservation. Grasslands also improve the aesthetic character of the land- scape, provide scenic vistas and open space, provide recreational opportu- nities, and protect the soil from water and wind erosion.

Large expanses of grassland acreage are annually threatened by conversion to other land uses such as cropland

and urban development. About half of all grasslands in the u.S. have been lost since settle- ment, much due to conversion to agricultural uses.

Wetland Habitat Wetlands are complex ecosystems that provide many ecological functions that are valued by society. they take many forms, including prairie potholes, bottomland hardwood swamps, coastal salt marshes, and playa wetlands. Wetlands are known to be the most biologically productive landscapes in temperate regions. More than one-third of the united States’ threat- ened and endangered species live only in wetlands, and nearly half use wetlands at some point in their lives. Most freshwater fish depend on wetlands at some stage of their lives. Many bird species are dependent on wetlands for either resting places during migration, nesting or feeding grounds, or cover from predators. Wetlands are also critical habitat for many amphibians and fur bearing mammals. Besides supporting wildlife, wetlands also con- trol water pollution and flooding, protect the water supply, and provide recreation.

When the country was first settled there were 221–224 million acres of wetlands in the continental u.S. Since then, about half have been drained and converted to other uses, nearly 85 percent for agricul- tural uses. currently, there are about 111 million acres of wetlands on nonfederal lands. About 15 percent are on agricul- tural lands (cropland, pastureland, and rangeland).

Consider This Many people think of wetlands just as swamps, and swamps as places of pesti- lence and disease. Why does it matter then that tens of millions of acres of wetlands have been converted to agricultural uses in the united States?

. Roger Calger/iStock/Thinkstock

Grasslands support the livestock industries of the surrounding communities and contribute to the overall environmental quality of a region.

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Apply Your Knowledge It’s clear from this reading that conventional agricultural practices impose significant costs on society in the form of decreased water quality, air quality, and wildlife habitat. For the most part these costs are not counted or factored into the price of the food we buy, although they are borne by society in other ways such as through higher taxes to pay for water treatment and health care costs. Environmental scientists and economists refer to these kinds of costs as external costs. Develop an inventory of the major environmental impacts of conventional agri- culture and how they might impose external costs on society. next, ask yourself who might be paying these external costs and how. Finally, ask yourself how our approach to agriculture might change if major agricultural producers were forced to pay directly for these external costs.

Riparian Habitat riparian areas are the zones along water bodies that serve as interfaces between terrestrial and aquatic ecosystems. riparian ecosystems generally compose a minor proportion of the landscape, but they are typically more structurally diverse and more productive from a wild- life perspective than adjacent upland areas. this is especially true in the arid West. Studies in the Southwest show that riparian areas support a higher breeding diversity of birds than all other western habitats combined. In Arizona and new Mexico, at least 80 percent of all animals use riparian areas at some stage of their lives. Western riparian habitats contain the highest non-colonial avian breeding densities in north America.

riparian zones also support productive aquatic habitat. they stabilize streambanks, thus reducing streambank erosion and sedimentation. Detritus [non-living organic material, such as fallen leaves] from streamside vegetation provides energy to the stream ecosystem. Veg- etation also provides shade, preventing extreme temperature swings that are detrimental to healthy stream ecosystems. riparian areas also filter out sediment, nutrients, and pesticides in runoff, thereby protecting water quality.

no comprehensive national inventory has been completed on the status and trends of ripar- ian areas. However, nrcS estimates that the conterminous u.S. originally contained 75–100 million acres of riparian habitats and that between 25 and 35 million acres remain.

Implications for Policy Agriculture has wide ranging impacts on environmental resources. Because of this, it also has the capacity to provide a wide range of environmental services. understanding the links between agriculture and environmental quality enhances our ability to design programs that best meet the needs of producers and those who value the services the environment can provide.

Adapted from USDA Economic Research Service. 2009 (updated). Environmental Interactions with Agricultural Production: Background. Retrieved from http://www.ers.usda.gov/Briefing/AgAndEnvironment/background.htm

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SEctIon 3.3 The debaTe over GeneTiCally ModiFied (GM) Foods

3.3 The Debate Over Genetically Modified (GM) Foods The opening article for this chapter asked what the next agricultural revolution would look like—would it be one focused on new forms of genetic engineering or one based on the concept of agroecology or sustainable agriculture. In the following article, Natasha Gilbert of the journal nature reviews some of the issues swirling around the debate over genetically modified (GM) crops. She concludes by stating that “stories, in favour of or against GM crops, will always miss the bigger picture, which is nuanced, equivocal and undeniably messy.” Regardless of that cau- tionary plea, the debate over GM crops remains one of the most contentious and emotional in the field of environmental science.

Unlike the first green revolution, which was achieved mainly through traditional plant-breeding approaches, genetic modification of crops represents a fundamentally new technology. Tradi- tional plant breeding sought to cross-breed or combine traits from the same plant types to pro- duce a new and better variety. For example, a rice plant that produced a lot of grain but blew over easily in the wind could be cross-bred with another rice plant that produced less grain but had a stronger stem and could withstand the wind. The resulting rice plant, after repeated breeding, would feature both desirable traits—high grain production and stoutness—in a single seed. In contrast, genetic modification works by removing genetic material from one organism and inserting it into the DNA of another, often in “novel” ways or in combinations that would never occur in nature (for example, inserting fish genes into a tomato plant).

As with traditional plant breeding, genetic engineering seeks to develop plants that feature cer- tain desirable traits. These could include developing plants that feature “input” traits such as resistance to pests or resistance to fungus and disease or plants that can withstand frost or drought conditions. This could also include developing “output” traits such as plants that have much higher nutritional content than traditional varieties.

The use of genetically engineered crops has grown rapidly in countries such as the United States, especially for soybeans, corn, and cotton where GM crops make up between 70 and 90 percent of total production (Figure 3.1). This rapid growth has raised concerns about the environmental, health, and economic impacts of widespread use of genetically engineered crops. As you review this reading consider the ways in which scientists might make use of the scientific method both to develop new genetically modified crops as well as to test whether these crops might have negative impacts on human health or the environment. Also be prepared to test your own beliefs on this subject in an assignment at the end of this section.

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SEctIon 3.3 The debaTe over GeneTiCally ModiFied (GM) Foods

Figure 3.1: Genetically engineered crops

the adoption of genetically engineered crops, including herbicide-tolerant (Ht) crops and insect- resistant crops engineered with Bacillus thuringiensis, has increased significantly since 1996.

Based on data from USDA. Retrieved from http://www.ers.usda.gov/media/185551/biotechcrops.html

By Natasha Gilbert In the pitched debate over genetically modified (GM) foods and crops, it can be hard to see where scientific evidence ends and dogma and speculation begin. In the nearly 20 years since they were first commercialized, GM crop technologies have seen dramatic uptake. Advocates say that they have increased agricultural production by more than uS$98 billion and saved an estimated 473 million kilograms of pesticides from being sprayed. But critics question their environmental, social and economic impacts.

researchers, farmers, activists and GM seed companies all stridently promote their views, but the scientific data are often inconclusive or contradictory. complicated truths have long been obscured by the fierce rhetoric. “I find it frustrating that the debate has not moved on,” says Dominic Glover, an agricultural socioeconomist at Wageningen university and research cen- tre in the netherlands. “the two sides speak different languages and have different opinions on what evidence and issues matter,” he says.

Here, Nature takes a look at three pressing questions: are GM crops fuelling the rise of herbicide-resistant ‘superweeds’? Are they driving farmers in India to suicide? And are the foreign transgenes in GM crops spreading into other plants? these controversial case stud- ies show how blame shifts, myths are spread and cultural insensitivities can inflame debate.

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GM Crops Have Bred Superweeds: True Jay Holder, a farming consultant in Ashburn, Georgia, first noticed Palmer amaranth (Amaran- thus palmeri) in a client’s transgenic cotton fields about five years ago. Palmer amaranth is a particular pain for farmers in the southeastern united States, where it outcompetes cotton for moisture, light and soil nutrients and can quickly take over fields.

Since the late 1990s, uS farmers had widely adopted GM cotton engineered to tolerate the herbicide glyphosate, which is marketed as roundup by Monsanto in St Louis, Missouri. the herbicide–crop combination worked spectacularly well—until it didn’t. In 2004, herbicide- resistant amaranth was found in one county in Georgia; by 2011, it had spread to 76. “It got to the point where some farmers were losing half their cotton fields to the weed,” says Holder.

Some scientists and anti-GM groups warned that GM crops, by encouraging liberal use of glyphosate, were spurring the evolution of herbicide resistance in many weeds. twenty-four glyphosate-resistant weed species have been identified since roundup-tolerant crops were introduced in 1996. But herbicide resistance is a problem for farmers regardless of whether they plant GM crops. Some 64 weed species are resistant to the herbicide atrazine, for exam- ple, and no crops have been genetically modified to withstand it.

Still, glyphosate-tolerant plants could be considered victims of their own success. Farm- ers had historically used multiple herbicides, which slowed the development of resistance. they also controlled weeds through ploughing and tilling—practices that deplete topsoil and release carbon dioxide, but do not encourage resistance. the GM crops allowed growers to rely almost entirely on glyphosate, which is less toxic than many other chemicals and kills a broad range of weeds without ploughing. Farmers planted them year after year without rotat- ing crop types or varying chemicals to deter resistance.

Glyphosate-resistant weeds have now been found in 18 countries worldwide, with signifi- cant impacts in Brazil, Australia, Argentina and Paraguay, says Ian Heap, director of the Inter- national Survey of Herbicide resistant Weeds, based in corvallis, oregon. And Monsanto has changed its stance on glyphosate use, now recommending that farmers use a mix of chemical products and ploughing. But the company stops short of acknowledging a role in creating the problem.

on balance, herbicide-resistant GM crops are less damaging to the environment than con- ventional crops grown at industrial scale. A study by PG Economics, a consulting firm in Dorchester, uK, found that the introduction of herbicide-tolerant cotton saved 15.5 million kilograms of herbicide between 1996 and 2011, a 6.1% reduction from what would have been used on conventional cotton. And GM crop technology delivered an 8.9% improvement to the environmental impact quotient—a measure that considers factors such as pesticide toxicity to wildlife—says Graham Brookes, co-director of PG Economics and a co-author of the industry-funded study, which many scientists consider to be among the field’s most extensive and authoritative assessments of environmental impacts.

the question is how much longer those benefits will last. So far, farmers have dealt with the proliferation of resistant weeds by using more glyphosate, supplementing it with other herbi- cides and ploughing. A study by David Mortensen, a plant ecologist at Pennsylvania State uni- versity in university Park, predicts that total herbicide use in the united States will rise from around 1.5 kilograms per hectare in 2013 to more than 3.5 kilograms per hectare in 2025 as a direct result of GM crop use.

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to offer farmers new weed-control strategies, Monsanto and other biotechnology compa- nies, such as Dow AgroSciences, based in Indianapolis, Indiana, are developing new herbi- cide-resistant crops that work with different chemicals, which they expect to commercialize within a few years.

Mortensen says that the new technologies will lose their effectiveness as well. But abandon- ing chemical herbicides completely is not a viable solution, says Jonathan Gressel, a weed scientist at the Weizmann Institute of Science in rehovot, Israel. using chemicals to control weeds is still more efficient than ploughing and tilling the soil, and is less environmentally damaging. “When farmers start to use more sustainable farming practices together with mix- tures of herbicides they will have fewer problems,” he says.

GM Cotton Has Driven Farmers to Suicide: False During an interview in March, Vandana Shiva, an environmental and feminist activist from India, repeated an alarming statistic: “270,000 Indian farmers have committed suicide since Monsanto entered the Indian seed market,” she said. “It’s a genocide.”

the claim, based on an increase in total suicide rates across the country in the late 1990s, has become an oft-repeated story of corporate exploitation since Monsanto began selling GM seed in India in 2002.

Bt cotton, which contains a gene from the bacterium Bacillus thuringiensis to ward off cer- tain insects, had a rough start. Seeds initially cost five times more than local hybrid varieties, spurring local traders to sell packets containing a mix of Bt and conventional cotton at lower prices. the sham seeds and misinformation about how to use the product resulted in crop and financial losses. this no doubt added strain to rural farmers, who had long been under the pressures of a tight credit system that forced them to borrow from local lenders.

But, says Glover, “it is nonsense to attribute farmer suicides solely to Bt cotton”. Although financial hardship is a driving factor in suicide among Indian farmers, there has been essen- tially no change in the suicide rate for farmers since the introduction of Bt cotton.

that was shown by researchers at the International Food Policy research Institute in Wash- ington Dc, who scoured government data, academic articles and media reports about Bt cot- ton and suicide in India. their findings, published in 2008 and updated in 2011, show that the total number of suicides per year in the Indian population rose from just under 100,000 in 1997 to more than 120,000 in 2007. But the number of suicides among farmers hovered at around 20,000 per year over the same period.

And since its rocky beginnings, Bt cotton has benefited farmers, says Matin Qaim, an agricul- tural economist at Georg August university in Göttingen, Germany, who has been studying the social and financial impacts of Bt cotton in India for the past 10 years. In a study of 533 cotton-farming households in central and southern India, Qaim found that yields grew by 24% per acre between 2002 and 2008, owing to reduced losses from pest attacks. Farmers’ profits rose by an average of 50% over the same period, owing mainly to yield gains. Given the profits, Qaim says, it is not surprising that more than 90% of the cotton now grown in India is transgenic.

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Glenn Stone, an environmental anthro- pologist at Washington university in St Louis, says that the empirical evidence for yield increases with Bt cotton is lack- ing. He has conducted original field stud- ies and analysed the research literature on Bt cotton yields in India, and says that most peer-reviewed studies report- ing yield increases with Bt cotton have focused on short time periods, often in the early years after the technology came online. this, he says, introduced biases: farmers who adopted the technology first tended to be wealthier and more educated, and their farms were already producing higher-than-average yields of conventional cotton. they achieved high

yields of Bt cotton partly because they lavished the expensive GM seeds with care and atten- tion. the problem now is that there are hardly any conventional cotton farms left in India to compare GM yields and profits against, says Stone. Qaim agrees that many studies showing financial gains focus on short-term impacts, but his study, published in 2012, controlled for these biases and still found continued benefits.

Bt cotton did not cause suicide rates to spike, says Glover, but neither is it the sole reason for the yield improvements. “Blanket conclusions that the technology is a success or failure lack the right level of nuance,” he says. “It’s an evolving story in India, and we have not yet reached a definitive conclusion.”

Transgenes Spread to Wild Crops in Mexico: Unknown In 2000, some rural farmers in the mountains of oaxaca, Mexico, wanted to gain organic certi- fication for the maize (corn) they grew and sold in the hope of generating extra income. David Quist, then a microbial ecologist at the university of california, Berkeley, agreed to help in exchange for access to their lands for a research project. But Quist’s genetic analyses uncov- ered a surprise: the locally produced maize contained a segment of the DnA used to spur expression of transgenes in Monsanto’s glyphosate-tolerant and insect-resistant maize.

GM crops are not approved for commercial production in Mexico. So the transgenes probably came from GM crops imported from the united States for consumption and planted by local farmers who probably didn’t know that the seeds were transgenic. Quist speculated at the time that the local maize probably cross-bred with these GM varieties, thereby picking up the transgenic DnA.

When the discovery was published in Nature, a media and political circus descended on oax- aca. Many vilified Monsanto for contaminating maize at its historic origin—a place where the crop was considered sacred. And Quist’s study came under fire for technical deficiencies, including problems with the methods used to detect the transgenes and the authors’ con- clusion that transgenes can fragment and scatter throughout the genome. Nature eventually withdrew support for the paper but stopped short of retracting it. “the evidence available is

Consider This consumer and health advocates are con- cerned that GM crops with truly novel traits, such as sunflower plants containing fish genes, pose a risk to society and that their approval and development is occur- ring too rapidly. Some argue that GM crops should be banned altogether, while others argue for longer trial and testing periods to ensure safety. What do you think? Are the potential risks worth it if GM crops can increase agricultural productivity?

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not sufficient to justify the publication of the original paper,” read an editorial footnote to a critique of the research published in 2002.

Since then, few rigorous studies of transgene flow into Mexican maize have been published, owing mainly to a dearth of research funding, and they show mixed results. In 2003–04, Alli- son Snow, a plant ecologist at ohio State university in columbus, sampled 870 plants taken from 125 fields in oaxaca and found no transgenic sequences in maize seeds.

But in 2009, a study led by Elena Alvarez-Buylla, a molecular ecologist at the national Auton- omous university of Mexico in Mexico city, and Alma Piñeyro-nelson, a plant molecular geneticist now at the university of california, Berkeley, found the same transgenes as Quist in three samples taken from 23 sites in oaxaca in 2001, and in two samples taken from those sites in 2004. In another study, Alvarez-Buylla and her co-authors found evidence of trans- genes in a small percentage of seeds from 1,765 households across Mexico. other studies conducted within local communities have found transgenes more consistently, but few have been published.

Snow and Alvarez-Buylla agree that differences in sampling methods can lead to discrepan- cies in transgene detection. “We sampled different fields,” says Snow. “they found them but we didn’t.”

the scientific community remains split on whether transgenes have infiltrated maize popula- tions in Mexico, even as the country grapples with whether to approve commercialization of Bt maize.

“It seems inevitable that there will be a movement of transgenes into local maize crops,” says Snow. “there is some proof that it is happening, but it is very difficult to say how common it is or what are the consequences.” Alvarez- Buylla argues that the spread of trans- genes will harm the health of Mexican maize and change characteristics, such as a variety’s look and taste, that are important to rural farmers. once the transgenes are present, it will be very difficult, if not impossible, to get rid of them, she says. critics speculate that GM traits that accumulate in the genomes of local maize populations over time could eventually affect plant fitness by using up energy and resources or by disrupt- ing metabolic processes, for example.

Snow says that there is no evidence so far for negative effects. And she expects that if the transgenes now in use drift to other plants, they will have neutral or beneficial effects on plant growth. In 2003, Snow and her colleagues showed that when Bt sunflowers (Heli- anthus annuus) were bred with their wild counterparts, transgenic offspring still required the same kind of close care as its cultivated parent but were less vulnerable to insects and

AP Photo/Natacha Pisarenko

A Spanish protest sign posted on a fence where Monsanto is building its largest seed production plant in Latin America in Cordoba, Argentina reads “Stop looting and contaminating! Monsanto out of Cordoba and Argentina.”

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SEctIon 3.3 The debaTe over GeneTiCally ModiFied (GM) Foods

produced more seeds than non-transgenic plants. Few similar studies have been conducted, says Snow, because the companies that own the rights to the technology are generally unwill- ing to let academic researchers perform the experiments.

In Mexico, the story goes beyond potential environmental impacts. Kevin Pixley, a crop sci- entist and the director of the genetic resources programme at the International Maize and Wheat Improvement centre in El Batan, Mexico, says that scientists arguing on behalf of GM technologies in the country have missed a crucial point. “Most of the scientific community doesn’t understand the depth of the emotional and cultural affiliation maize has for the Mexi- can population,” he says.

tidy stories, in favour of or against GM crops, will always miss the bigger picture, which is nuanced, equivocal and undeniably messy. transgenic crops will not solve all the agricultural challenges facing the developing or developed world, says Qaim: “It is not a silver bullet.” But vilification is not appropriate either. the truth is somewhere in the middle.

Adapted from Gilbert, N. (2013, May 02). Case studies: A hard look at GM crops. nature, 497, 24–26. doi:10.1038 /497024a. Retrieved from http://www.nature.com/news/case-studies-a-hard-look-at-gm-crops-1.12907. Reprinted by permission from Macmillan Publishers Ltd. Natasha Gilbert, “Case studies: A hard look at GM crops,” Nature 497, 24–26. Copyright © 2013.

Apply Your Knowledge the degree to which the scientific, ethical, and political debate over GM crops has become heated can be seen in the language used by those involved. opponents of GM crops refer to them as “Frankenfoods” and accuse giant biotechnology firms like Monsanto of driving farmers to suicide in their pursuit of profit. Proponents of GM crops accuse opponents of being anti-science extremists who are responsible for the starvation and death of children in poor countries. As the previous article concluded, however, the truth is likely somewhere in the middle.

In order to test your own knowledge and opinion on GM crops it’s important to first start with some background material. the links below will help you better understand some of the basic issues surrounding GM crops, such as

• health risks associated with GM crops including the development of new allergens and toxins in foods;

• ecological risks and unintended side effects, including the spread of herbicide-resistant weeds, the transfer of genes from GM crops to non-GM crops, and unexpected impacts on wildlife.

these readings, like the debate itself, tend to come down more on one side or the other, but they are relatively balanced and help introduce the major issues. review them to enhance your knowledge of this subject.

• http://www.fas.org/biosecurity/education/dualuse-agriculture/2.-agricultural -biotechnology/genetically-engineered-crops.html

• http://www.who.int/foodsafety/publications/biotech/en/20questions_en.pdf

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SEctIon 3.4 GLoBAL FISHErIES

3.4 Global Fisheries Seafood provides for roughly 15 percent of all animal protein consumed globally by humans, and this percentage is much higher in some developing countries. Therefore, managing global fisheries is equally as important as the way agriculture is sustained. In this article, Paul Green- berg of national Geographic Magazine reviews trends in the global fish catch and introduces the concept of the “seafood print” as a means of measuring the environmental impact of different kinds of fish consumption.

Rather than look at just the volume of seafood harvested from a fishery, the seafood print approach focuses on the type of fish caught. Fish that are at or near the top of the food chain, and with essentially no predators of their own (such as Bluefin tuna), are known as apex or top predators. Apex fish consume large amounts of smaller fish in order to survive and grow, and in turn these smaller fish eat even larger amounts of fish that are lower on the food chain—this is the same concept as trophic levels introduced in section 1.2. As a result, harvesting and eating one ton of Bluefin tuna actually has a much larger seafood print than eating many more tons of fish overall. This same concept of eating higher on the food chain applies to meat as well. In order to produce one ton of meat, we need many more tons of grain. This is one of the reasons for the concern over grain supplies reviewed in section 3.1.

To deal with these interrelated issues in food production, scientists focus on the concept of pri- mary production (also reviewed in section 1.2) to develop a measure such as the seafood print. In the ocean, most primary production is accomplished by algae known as phytoplankton, and these serve as the base of the oceanic food web. Phytoplankton are eaten by small floating animals

Apply Your Knowledge (continued) • http://www.ucsusa.org/food_and_agriculture/our-failing-food-system/genetic

-engineering/risks-of-genetic-engineering.html • http://www.fda.gov/Food/FoodScienceresearch/Biotechnology/ucm346030.htm • http://www.isaaa.org/resources/publications/pocketk/1/

once you have reviewed this material, visit this site, which will allow you to vote on whether we should grow GM crops or not (http://www.pbs.org/wgbh/harvest/exist/). Start by read- ing the Introduction and then answering the yes/no question at the bottom of the page. Based on your first and subsequent answers you will repeatedly be challenged in your beliefs. Work through all of the questions. on the final page you’ll have a chance to review all 12 arguments for and against GM crops (six in favor and six opposed). Have a look at these and then ask yourself the following questions:

• What side did you tend to favor in the debate? How strong was your support for that side? • What arguments did you find most compelling in forming your own opinion? Why did

you find these so important? • Given the uncertainty and complexity involved in the debate over GM crops, how should

we, as a society, regulate their development and use? • What was the most important lesson you learned from this exercise?

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SEctIon 3.4 GLoBAL FISHErIES

known as zooplankton, which, in turn, are eaten by small fish such as sardines and menhaden. These small fish then become the food source for larger fish and apex predators like the bluefin tuna. In the same way, the impacts of moving fish production to fish farms, or aquaculture, will depend on the type of fish being raised. For example, farm- raised salmon are fed large amounts of fish meal from wild-caught stocks of small fish and so they have a significant seafood print, Whereas farm-raised tilapia eat mainly plant material and so have a smaller seafood print. These and other issues surrounding global fisheries are discussed below.

By Paul Greenberg Every year more than 170 billion pounds (77.9 million metric tons) of wild fish and shellfish are caught in the oceans—roughly three times the weight of every man, woman, and child in the united States. Fisheries managers call this overwhelming quantity of mass-hunted wild- life the world catch, and many maintain that this harvest has been relatively stable over the past decade. But an ongoing study conducted by Daniel Pauly, a fisheries scientist at the uni- versity of British columbia, in conjunction with Enric Sala, a national Geographic fellow, sug- gests that the world catch is neither stable nor fairly divided among the nations of the world. In the study, called SeafoodPrint and supported by the Pew charitable trusts and national Geographic, the researchers point the way to what they believe must be done to save the seas.

they hope the study will start by correcting a common misperception. the public imagines a nation’s impact on the sea in terms of the raw tonnage of fish it catches. But that turns out to give a skewed picture of its real impact, or seafood print, on marine life. “the problem is, every fish is different,” says Pauly. “A pound of tuna represents roughly a hundred times the footprint of a pound of sardines.”

the reason for this discrepancy is that tuna are apex predators, meaning that they feed at the very top of the food chain. the largest tuna eat enormous amounts of fish, including intermediate-level predators like mackerel, which in turn feed on fish like anchovies, which prey on microscopic copepods [small crustaceans]. A large tuna must eat the equivalent of its body weight every ten days to stay alive, so a single thousand-pound tuna might need to eat as many as 15,000 smaller fish in a year. Such food chains are present throughout the world’s ocean ecosystems, each with its own apex animal. Any large fish—a Pacific swordfish, an Atlantic mako shark, an Alaska king salmon, a chilean sea bass—is likely to depend on several levels of a food chain.

. Vik Thomas/iStock/Thinkstock

the impact of aquaculture depends on the fish stocks raised on the farm. Salmon and tuna farms have a higher seafood print than do farms producing smaller fish.

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SEctIon 3.4 GLoBAL FISHErIES

The SeafoodPrint to gain an accurate picture of how different nations have been using the resources of the sea, the SeafoodPrint researchers needed a way to compare all types of fish caught. they decided to do this by measuring the amount of “primary production”—those microscopic organisms at the bottom of the marine food web—required to make a pound of a given type of fish. they found that a pound of bluefin tuna, for example, might require a thousand pounds or more of primary production.

In assessing the true impact that nations have on the seas, the team needed to look not just at what a given nation caught but also at what the citizens of that nation ate. “A country can acquire primary production by fishing, or it can acquire it by trade,” Pauly says. “It is the sheer power of wealthy nations to acquire primary production that is important.”

nations with money tend to buy a lot of fish, and a lot of the fish they buy are large apex preda- tors like tuna. Japan catches less than five million metric tons of fish a year, a 29 percent drop from 1996 to 2006. But Japan consumes nine million metric tons a year, about 582 million metric tons in primary-production terms. though the average chinese consumer generally eats smaller fish than the average Japanese consumer does, china’s massive population gives it the world’s biggest seafood print, 694 million metric tons of primary production. the u.S., with both a large population and a tendency to eat apex fish, comes in third: 348.5 million metric tons of primary production. And the size of each of these nations’ seafood prints is growing. What the study points to, Pauly argues, is that these quantities are not just extremely large but also fundamentally unsustainable.

Overfishing Exactly how unsustainable can be seen in global analyses of seafood trade compiled by Wilf Swartz, an economist working on SeafoodPrint. Humanity’s consumption of the ocean’s pri- mary production changed dramatically from the 1950s to the early 2000s. In the 1950s much less of the ocean was being fished to meet our needs. But as affluent nations increasingly demanded apex predators, they exceeded the primary-production capacities of their exclu- sive economic zones, which extend up to 200 nautical miles from their coasts. As a result, more and more of the world’s oceans had to be fished to keep supplies constant or growing.

Areas outside of these zones are known in nautical parlance as the high seas. these vast ter- ritories, the last global commons on Earth, are technically owned by nobody and everybody. the catch from high-seas areas has risen to nearly ten times what it was in 1950, from 1.6 million metric tons to around 13 million metric tons. A large part of that catch is high-level, high-value tuna, with its huge seafood print.

the wealthier nations that purchase most of the products of these fisheries are essentially privatizing them. Poorer countries simply cannot afford to bid for high-value species. citizens in these nations can also lose out if their governments enter into fishing or trade agreements with wealthier nations. In these agreements local fish are sold abroad and denied to local citizens—those who arguably have the greatest need to eat them and the greatest right to claim them.

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SEctIon 3.4 GLoBAL FISHErIES

Although supermarkets in developed nations like the u.S. and Japan still abound with fish flesh, SeafoodPrint suggests that this abundance is largely illusory because it depends on these two troubling phenomena: broader and broader swaths of the high seas transformed from fallow commons into heavily exploited, monopolized fishing grounds; and poor nations’ seafood wealth spirited away by the highest bidder.

Humanity’s demand for seafood has now driven fishing fleets into every virgin fish- ing ground in the world. there are no new grounds left to exploit. But even this isn’t enough. An unprecedented buildup of fish- ing capacity threatens to outstrip seafood supplies in all fishing grounds, old and new. A report by the World Bank and the Food and Agriculture organization (FAo) of the united nations recently concluded that the ocean doesn’t have nearly enough fish left to support the current onslaught. Indeed, the report suggests that even if we had half as many boats, hooks, and nets as we do now, we would still end up catching too many fish.

Some scientists, looking at the same data, see a different picture than Daniel Pauly does. ray Hilborn, a fisheries scientist at the university of Washington, doesn’t think the situation is so dire. “Daniel is fond of showing a graph that suggests that 60 to 70 percent of the world’s fish stocks are overexploited or collapsed,” he says. “the FAo’s analysis and independent work I have done suggests that the number is more like 30 percent.” Increased pressure on seafood shouldn’t come as a surprise, he adds, since the goal of the global fishing industry is to fully exploit fish populations, though without damaging their long-term viability.

The SeafoodPrint in Action Many nations, meanwhile, are trying to compensate for the world’s growing seafood deficit by farming or ranching high-level predators such as salmon and tuna, which helps maintain the illusion of abundance in the marketplace. But there’s a big problem with that approach: nearly all farmed fish consume meal and oil derived from smaller fish. this is another way that SeafoodPrint might prove useful. If researchers can tabulate the ecological value of wild fish consumed on fish farms, they could eventually show the true impact of aquaculture [fish farming].

Given such tools, policymakers might be in a better position to establish who is taking what from the sea and whether that is just and sustainable. As a global study, SeafoodPrint makes clear that rich nations have grossly underestimated their impacts. If that doesn’t change, the abundance of fish in our markets could drop off quickly. Most likely the wealthy could still enjoy salmon and tuna and swordfish. But middle-class fish-eaters might find their seafood options considerably diminished, if not eliminated altogether.

Consider This Both Daniel Pauly and ray Hilborn are respected fisheries scientists. Yet one of them estimates that 60–70 percent of the world’s fish stocks are overexploited, while the other suggests this number is closer to 30 percent. Why might two scien- tists come to such different conclusions? What is it about understanding wild fish- eries, in particular, that makes developing such an estimate difficult?

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SEctIon 3.4 GLoBAL FISHErIES

What then is SeafoodPrint’s long-range potential? could some version of it guide a conserva- tion agreement in which nations are given a global allowance of oceanic primary production and fined or forced to mend their ways if they exceed it?

“that would be nice, wouldn’t it?” Pauly says. He points out that we already know several ways to shrink our impact on the seas: reduce the world’s fishing fleets by 50 percent, estab- lish large no-catch zones, limit the use of wild fish as feed in fish-farming. unfortunately, the seafood industry has often blocked the road to reform.

SeafoodPrint could also give consumers a map around that roadblock—a way to plot the course toward healthy, abundant oceans. today there are dozens of sustainable-seafood cam- paigns, each of which offers suggestions for eating lower on the marine food chain. these include buying farmed tilapia instead of farmed salmon, because tilapia are largely herbiv- orous and eat less fish meal when farmed; choosing trap-caught black cod over long-lined chilean sea bass, because fewer unwanted fish are killed in the process of the harvest; and avoiding eating giant predators like Atlantic bluefin tuna altogether, because their numbers are simply too low to allow any harvest at all.

Protecting the Seas the problem, say conservationists, is that the oceans have reached a critical point. Simply changing our diets is no longer sufficient if fish are to recover and multiply in the years ahead. What Pauly and other conservation biologists now believe is that suggestions must be transformed into obligations. If treaties can establish seafood-consumption targets for every nation, they argue, citizens could hold their governments responsible for meeting those tar- gets. comparable strategies have worked to great effect in terrestrial ecosystems, for trade items such as furs or ivory. the ocean deserves a similar effort, they say.

“Barely one percent of the ocean is now protected, compared with 12 percent of the land,” Enric Sala adds, “and only a fraction of that is fully protected.” that’s why national Geographic is partnering with governments, businesses, conservation organizations, and citizens to pro- mote marine reserves and help reduce the impact of fishing around the globe.

In the end, neither Pauly nor Sala nor the rest of the SeafoodPrint team wants to destroy the fishing industry, eliminate aquaculture, or ban fish eating. What they do want to change is business as usual. they want to let people know that today’s fishing and fish-farming prac- tices are not sustainable and that the people who advocate maintaining the status quo are failing to consider the ecological and economic ramifications. By accurately measuring the impacts nations have on the sea, SeafoodPrint may lay the groundwork for effective change, making possible the rebuilding of the ocean’s dwindling wealth. Such a course, Pauly believes, could give the nations of the world the capability, in the not too distant future, to equita- bly share a truly bountiful, resurrected ocean, rather than greedily fight over the scraps that remain in the wake of a collapse.

Adapted from Greenberg, P. (2010). Time for a Sea Change. national Geographic Magazine. Retrieved from http:// ngm.nationalgeographic.com/print/2010/10/seafood-crisis/greenberg-text. Paul Greenberg/National Geo- graphic Creative. Used by permission.

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SEctIon 3.5 Case hisTory—The rise oF The loCal Foods MoveMenT

3.5 Case History—The Rise of the Local Foods Movement Our modern food system not only provides us with an abundance of food at relatively low prices, it also allows us to eat different foods at almost any time of the year, even if they are out of season. Earlier generations of Americans expected to have fresh strawberries only in June or July and fresh apples in September and October. Today, however, fresh strawberries and apples, as well as raspberries, grapes, peaches, beans, and mangoes, are available in supermarkets throughout the year.

This trend, combined with increased consumption of processed foods and the concentration of meat production has given rise to a concept known as “food miles.” Food miles are a measure of how far our food travels on average from where it is produced to where it is consumed. Since transport of food requires the use of fossil fuels, an increase in food miles is likely to increase the overall environmental impact of that product. Recent studies have found that most supermarket produce has traveled an average of 1,500 miles, and one study estimated that it requires 435 calories of fossil fuel energy to transport a 5-calorie strawberry from California to New York (Cohen, 2008).

Awareness of the environmental impacts of food miles combined with growing concern over food safety have led more and more Americans to grow their own food or seek out local producers. In this article, Lester Brown of the Worldwatch Institute summarizes these trends and argues that they could be the early signs of a more fundamental shift in the way food is grown, marketed, and consumed in this country. Brown argues that a shift to purchasing more local foods can sig- nificantly decrease food miles and reduce other environmental impacts of conventional agricul- ture. For example, more localized livestock production can address some of the problems caused by concentrated animal feeding operations (CAFOs) and encourage a return to integrated crop- livestock operations that characterized almost all agricultural systems until very recently.

By L. Brown In the united States, there has been a surge of interest in eating fresh local foods, corresponding with mounting concerns about the climate effects of consuming food from distant places and about the obesity and other health problems associated with junk food diets. this is reflected in the rise in urban gardening, school gardening, and farmers’ markets.

With the fast-growing local foods move- ment, diets are becoming more locally shaped and more seasonal. In a typical supermarket in an industrial country today it is often difficult to tell what sea- son it is because the store tries to make everything available on a year-round

. Vasiliki Varvaki/iStock/Thinkstock

Many people find locally grown food to be fresher than foods shipped thousands of miles, and enjoy purchasing directly from farmers.

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SEctIon 3.5 Case hisTory—The rise oF The loCal Foods MoveMenT

basis. As oil prices rise, this will become less common. In essence, a reduction in the use of oil to transport food over long distances—whether by plane, truck, or ship—will also localize the food economy.

this trend toward localization is reflected in the recent rise in the number of farms in the united States, which may be the reversal of a century-long trend of farm consolidation. Between the agricultural census of 2002 and that of 2007, the number of farms in the united States increased by 4 percent to roughly 2.2 million. the new farms were mostly small, many of them operated by women, whose numbers in farming jumped from 238,000 in 2002 to 306,000 in 2007, a rise of nearly 30 percent.

Many of the new farms cater to local markets. Some produce fresh fruits and vegetables exclusively for farmers’ markets or for their own roadside stands. others produce special- ized products, such as the goat farms that produce milk, cheese, and meat or the farms that grow flowers or wood for fireplaces. others specialize in organic food. the number of organic farms in the united States jumped from 12,000 in 2002 to 18,200 in 2007, increas- ing by half in five years.

Gardening Gardening was given a big boost in the spring of 2009 when u.S. First Lady Michelle obama worked with children from a local school to dig up a piece of lawn by the White House to start a vegetable garden. there was a precedent. Eleanor roosevelt planted a White House victory garden during World War II. Her initiative encouraged millions of victory gardens that even- tually grew 40 percent of the nation’s fresh produce.

Although it was much easier to expand home gardening during World War II, when the united States was largely a rural society, there is still a huge gardening potential—given that the grass lawns surrounding u.S. residences collectively cover some 18 million acres. converting even a small share of this to fresh vegetables and fruit trees could make an important contri- bution to improving nutrition.

Many cities and small towns in the united States and England are creating community gar- dens that can be used by those who would otherwise not have access to land for gardening. Providing space for community gardens is seen by many local governments as an essential service, like providing playgrounds for children or tennis courts and other sport facilities.

Local Markets Many market outlets are opening up for local produce. Perhaps the best known of these are the farmers’ markets where local farmers bring their produce for sale. In the united States, the number of these markets increased from 1,755 in 1994 to more than 4,700 in mid-2009, nearly tripling over 15 years. Farmers’ markets reestablish personal ties between produc- ers and consumers that do not exist in the impersonal confines of the supermarket. Many farmers’ markets also now take food stamps, giving low-income consumers access to fresh produce that they might not otherwise be able to afford. With so many trends now boosting interest in these markets, their numbers may grow even faster in the future.

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SEctIon 3.5 Case hisTory—The rise oF The loCal Foods MoveMenT

Schools In school gardens, children learn how food is produced, a skill often lacking in urban settings, and they may get their first taste of freshly picked peas or vine-ripened tomatoes. School gar- dens also provide fresh produce for school lunches. california, a leader in this area, has 6,000 school gardens.

Many schools and universities are now making a point of buying local food because it is fresher, tastier, and more nutritious, and it fits into new campus greening pro- grams. Some universities compost kitchen and cafeteria food waste and make the compost available to the farmers who sup- ply them with fresh produce.

Supermarkets are increasingly contract- ing with local farmers during the season when locally grown produce is available. upscale restaurants emphasize locally

grown food on their menus. In some cases, year-round food markets are evolving that mar- ket just locally produced foods, including not only fruit and vegetables but also meat, milk, cheese, eggs, and other farm products.

The Benefits of Local Food from more distant locations boosts carbon emissions while losing flavor and nutri- tion. A survey of food consumed in Iowa showed conventional produce traveled on average 1,500 miles, not including food imported from other countries. In contrast, locally grown produce traveled on average 56 miles—a huge difference in fuel investment. And a study in ontario, canada, found that 58 imported foods traveled an average of 2,800 miles. Simply put, consumers are worried about food security in a long-distance food economy. this trend has led to a new term: locavore, complementing the better known terms herbivore, carnivore, and omnivore. [. . .]

As agriculture localizes, livestock production will likely start to shift away from mega-sized cattle, hog, and poultry feeding operations. the shift from factory farm production of milk, meat, and eggs by returning to mixed crop-livestock operations facilitates nutrient recycling as local farmers return livestock manure to the land. the combination of high prices of natu- ral gas, which is used to make nitrogen fertilizer, and of phosphate, as reserves are depleted, suggests a much greater future emphasis on nutrient recycling—an area where small farmers producing for local markets have a distinct advantage over massive feeding operations.

In combination with moving down the food chain to eat fewer livestock products, reducing the food miles in our diets can dramatically reduce energy use in the food economy. And as world food insecurity mounts, more and more people will be looking to produce some of their own food in backyards, in front yards, on rooftops, in community gardens, and elsewhere, further contributing to the localization of agriculture.

Adapted from Chapter 9, “Feeding Eight Billion People Well,” in Lester R. Brown, Plan B 4.0: Mobilizing to Save civilization. Copyright © Earth Institute 2009. Retrieved from http://www.earth-policy.org/index.php?/book _bytes/2009/pb4ch09_ss5#”. Used by permission.

Consider This Besides providing students with fresh pro- duce, school gardens are also being touted as an important environmental education tool. What lessons and concepts from environ- mental science can students gain through the act of gardening?

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SuMMArY & rESourcES

Summary & Resources

chapter Summary In the last chapter, we learned that even though fertility rates are declining and population growth is slowing, global population is expected to reach over nine billion later this century. More people, combined with more widespread affluence and rising meat consumption, means we will have to continue to increase food production in order to feed the world. How that food is grown, processed, and distributed can have significant impacts on the environment, and there is concern that conventional approaches cannot be sustained over the long term.

one approach to increasing food production that began roughly 50 years ago was the first green revolution. this movement achieved remarkable success in raising global grain pro- duction at a time when world population was growing rapidly. Green revolution agriculture focused on monocultures of single crops and required significant inputs of energy, water,

Apply Your Knowledge Whether it’s water, energy, or food, we seldom stop to think where these critical items come from and how they get to us at the very moment we need them. How often do we stop and ask where our food comes from, how it’s grown, processed, and shipped to where we buy it? And yet our food consumption habits can have enormous impacts on the environment and our personal health. For this exercise complete the following steps:

Step 1—Sit down and list the kinds of foods you usually eat and how much of them you eat over the course of a typical week. It might help to break these down into fruits, veg- etables, meats (including seafood), dairy products, etc. List the top ten foods that you eat and try to estimate the quantity of your consumption over the course of the week. For example, this could be as simple as saying “five apples a week,” or as complicated as “five hamburgers a week, each weighing 1/3 pound, equaling 1.66 pounds of beef per week.” List these ten types of foods along with estimated consumption.

Step 2—Pick three of these top ten foods and determine where they typically come from. You’ll need to do a little sleuthing at the supermarket or on the Internet, but you should be able to determine where your favorite foods typically are produced. For example, you can visit a supermarket and look at boxes or signs to determine where most of the fruits and vegetables on display originate. A search on the Internet can tell you a lot about where most of the beef, pork, or chicken is produced in the united States.

Step 3—using knowledge you’ve gained from this chapter as well as some of the resources provided at the end of this chapter, list some of the significant environmental and health impacts associated with the growing, processing and distribution of these foods.

Step 4—use the Food carbon Emissions calculator found here (http://www.food emissions.com/foodemissions/calculator.aspx) to examine some of the impacts of your food consumption. Vary the food category, commodity, and assumptions about miles traveled and percentage wasted to see how this changes your results. How comprehen- sive is this calculator in terms of measuring the overall impact of your food consumption choices? What factors might it not be measuring?

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SuMMArY & rESourcES

fertilizers, pesticides, and herbicides. As with many issues in the study of the environment, we are confronted here with tradeoffs. the high-input approach to agriculture has increased food production dramatically, almost certainly averting famine in some regions and provid- ing an abundance of relatively cheap food in countries like the united States. However, this approach has also resulted in a number of environmental challenges, including the following:

• Heavy pumping of groundwater for irrigation has lowered water tables and resulted in salinization—the buildup of mineral salts in the soil—in many regions.

• Mechanization and continuous plowing has worsened soil erosion and the loss of top- soil, necessitating heavier use of synthetic fertilizers to make up for lost soil fertility.

• Fertilizer runoff from farms enters water bodies and can result in algal blooms, known as eutrophication. When the algae decompose, oxygen levels in the water are depleted, and this can result in the death of aquatic and marine life.

• Monocultures create ideal conditions for insect pests and weeds, necessitating heavy applications of chemical pesticides and herbicides to reduce crop losses.

• conventional agriculture is highly energy-intensive. Much of this energy is consumed in the production of synthetic fertilizers and pesticides, as well as in the processing and shipment of foods over long distances.

• Large-scale meat production from concentrated animal feeding operations has resulted in waste management problems and necessitated the greater use of antibi- otics to control the spread of disease—a situation that some experts worry is leading to the development of strains of antibiotic-resistant bacteria.

one solution being touted as a means of meeting this challenge is genetic engineering and the genetic modification of crops. this approach aims to develop specific traits in crops that would maintain productivity while reducing the need for inputs of water, fertilizer, and pesti- cides. Another approach, known as agroecology or sustainable agriculture, focuses on manag- ing a farm as an ecological system, paying attention to nutrient cycles, monitoring the inter- actions between plants and other organisms, and balancing resource use with availability. While these two approaches—genetic engineering and agroecology—need not be mutually exclusive, they are usually presented and discussed as if they were. ultimately, in order to continue feeding the world in the decades ahead, it may be that every possible option has to remain on the table.

Indeed, meeting the food demands of a growing population in a way that does not undermine the environment is one of the great challenges of our time. As we’ll see in the next chapter, growing food demands are already driving the conversion of tropical rainforests to farmland and the use of synthetic fertilizers at a rate that is actually beginning to change the global nitrogen and phosphorous cycles.

Working Toward Solutions the readings in this chapter might leave you feeling overwhelmed and pessimistic about the prospects for feeding the world in a sustainable fashion. However, there are thousands of examples from around the world of farmers, ranchers, fishers, and scientists working together to reduce the environmental impact of food production and meet the needs of a growing popu- lation. the discussion below highlights some of the approaches being used to improve

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Working Toward Solutions (continued) agricultural sustainability and the science, economics, and policy behind them. It also pro- vides some hints for what individuals can do to reduce the environmental impact of their own food consumption choices.

there are a whole range of approaches and practices that fall under the umbrella term of sus- tainable agriculture. the u.S. Department of Agriculture (uSDA) published a comprehensive survey of these in a 1999 report found here (http://www.nal.usda.gov/afsic/pubs/terms /srb9902.shtml). the report starts with a definition of what we mean by sustainable, some- thing we want to maintain or keep in existence over a long period of time. clearly, an approach to agriculture that depletes and pollutes water supplies, destroys soil resources, relies heavily on nonrenewable energy supplies, and poisons people and animals with pesticides and agri- cultural chemicals is not sustainable.

Sustainable alternatives, therefore, have to preserve water supplies and protect water quality, maintain soil health and productivity, rely primarily on renewable energy inputs and solar energy, and limit or eliminate the use of pesticides and other potentially hazardous agricultural chemicals. one approach to doing this is known as agroecology. Agroecology is an attempt to design and develop agricultural systems that mimic or copy natural, ecological systems. For example, consider that natural forest or grassland systems can be incredibly productive over long periods of time while generating positive environmental benefits (such as clean air and water) known as ecosystem services. these systems do not rely on external inputs of energy, water, or fertilizers or other chemicals to maintain their productivity. Agroecology seeks to do the same thing for agriculture.

Specific practices that are used in agroecology and sustainable agriculture might include the following:

• crop rotation—rather than plant the same crop year after year, farmers rotate crops over time. this approach disrupts pest reproduction cycles, reducing the need for pes- ticides, and can also reduce the need for fertilizer since different plants often require different nutrients.

• no-till and low-till farming—Growing crops without tilling or disturbing the soil reduces soil erosion and runoff.

• Soil-building crops—Some plants, such as clover and legumes, are capable of absorbing nitrogen from the atmosphere and depositing it in the soil, enhancing soil quality. these plants can be inter-cropped or planted alongside other crops to maintain soil fertility.

• Integrated pest management (IPM)—crop rotation, inter-cropping, and increased crop diversity generally lead to fewer pest problems than monocultures. IPM also seeks to maintain balance in a field between destructive pests and beneficial insects (such as ladybugs and praying mantises) that feed on them.

• organic agriculture—Minimizing or eliminating the use of synthetic fertilizers, pesticides, and herbicides through careful management of soil fertility and insect populations.

Despite the apparent benefits of these approaches there are political, economic, and other bar- riers to more widespread adoption of sustainable agricultural practices. For starters, govern- ment subsidies to agriculture in countries like the united States are often based on the amount

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Post-test

1. the poorest people on the planet spend from _______ to ________ percent of their income on food.

a. 10 to 20 b. 20 to 30 c. 30 to 50 d. 50 to 70

2. Which of the following is not an attribute that has an important impact on soil quality?

a. texture b. Depth c. color d. Permeability

3. A situation in which weeds evolve so that chemical sprays are no longer effective in controlling them is known as

a. pesticide resistance. b. herbicide resistance. c. nutrient management. d. chemical resistance.

Working Toward Solutions (continued) of acreage devoted to a specific crop. this encourages monocultures and discourages crop rotation and inter-cropping since these would reduce the size of the subsidy payment. Second, sustainable practices require a fair amount of knowledge, careful monitoring, and experimen- tation. Many farmers, already operating with heavy debt burdens, are reluctant to change the way they farm for fear of lower yields and profitability. Lastly, the societal costs of conven- tional agricultural practices—such as air and water pollution—are typically not reflected in the prices we pay for our food. this makes organic agriculture and food produced in a more sustainable fashion appear more expensive than it actually is.

As individuals we can support a move toward more sustainable agriculture by paying more attention to where our food comes from and how it is produced. Where possible, and when affordable, organic products are likely to have less environmental impact than non-organic. Supporting local farmers is another way to reduce the environmental impact of our food con- sumption. one way to do this is by joining a community-supported agriculture (cSA) group in your area. A cSA consists of a group of consumers who pay a local farmer a fixed price (or sub- scription) for a share of that farmer’s produce over the course of the year. You can learn more about sustainable agriculture and see if there are any cSAs in your area by going to these sites:

• http://www.nal.usda.gov/afsic/pubs/csa/csa.shtml • http://newfarm.rodaleinstitute.org/embedfarmlocator/ • http://www.localharvest.org/csa/

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4. A measure developed by marine biologists to estimate the amount of primary pro- duction required to make a pound of different kinds of fish is known as

a. the ecological footprint. b. the seafood print. c. the marine food web. d. sustainable production.

5. Which of the following is a method that promotes nutrient recycling? a. Having mega-sized livestock b. Having a chicken farm c. Having a mixed crop-livestock operation d. Having a corn and grain farm

6. rising demand for pork in china has led to the rapid expansion of soybean produc- tion and deforestation in

a. the united States. b. canada. c. Brazil. d. South Africa.

7. the major source of nitrogen and phosphorous pollution in the Gulf of Mexico is a. suburban sprawl. b. oil refineries. c. agriculture. d. mining.

8. the controversy over genetically modified (GM) crops has been especially serious in which of the following countries, where GM maize (corn) is believed to have mixed with traditional varieties?

a. Germany b. russia c. china d. Mexico

9. Which of the following is the BESt way to lower your individual seafood print? a. Eat farmed tilapia b. Eat farmed salmon c. Eat Bluefin tuna d. Eat chilean sea bass.

10. Which of these is the BESt explanation for the 4 percent growth in the number of farms in the u.S. between 2002 and 2007?

a. Growth in large farms producing soybeans for export to china b. Growth in small farms producing for local markets c. Growth in small farms producing for export d. Growth in large farms producing apples for export to France

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Answers 1. d. 50 to 70. the answer can be found in section 3.1. 2. c. color. the answer can be found in section 3.2. 3. b. herbicide resistance. the answer can be found in section 3.3. 4. b. the seafood print. the answer can be found in section 3.4. 5. c. Having a mixed crop-livestock operation. the answer can be found in section 3.5. 6. c. Brazil. the answer can be found in section 3.1. 7. c. agriculture. the answer can be found in section 3.2. 8. d. Mexico. the answer can be found in section 3.3. 9. a. Eat farmed tilapia. the answer can be found in section 3.4. 10. b. Growth in small farms producing for local markets. the answer can be found in section 3.5.

Key Ideas

• For the past 50 years, green revolution approaches to agriculture—combining new crop varieties with expanded irrigation, fertilizers, and pesticides to control pests and weeds—have greatly increased crop yields and helped avert famine in many regions of the world. However, agricultural productivity has begun to stagnate while rising populations, changing diets, and increased demand for biofuels from crops is putting increased pressure on global food supplies.

• Higher levels of meat consumption require even greater increases in grain produc- tion since it takes many more calories of grain fed to an animal to produce a single calorie of meat. A shift to more of a meat-based diet therefore increases the land area devoted to agriculture as well as the consumption of water, energy, and agricul- tural chemicals.

• close to half of America’s land area is dedicated to growing crops or pasture for animals. Agricultural activities on these lands can degrade soil quality, water quality, and air quality.

• Agriculture is the leading cause of impairment or pollution of America’s rivers and lakes. this includes sediment from soil erosion, runoff of nitrogen and phospho- rous fertilizers, and runoff of pesticides and herbicides. nitrogen and phosphorous runoff leads to algae blooms, eutrophication, and hypoxia, or low oxygen levels in water bodies.

• Agriculture is also an important contributor to air pollution in the form of nitrous oxides, methane, carbon dioxide, and particulates or dust.

• unlike traditional plant breeding, which combines traits from the same plant types to produce better varieties, genetic engineering or biotechnology involves moving genetic material from one organism to another, perhaps completely different, organ- ism. the goal of genetic engineering is to select genes that possess desirable traits, such as resistance to drought or insects, and insert them into another organism that does not already benefit from the desirable trait.

• Globally, over 170 billion pounds of wild fish and shell fish are caught in the oceans each year, and seafood accounts for roughly 15 percent of all animal protein con- sumed by humans. By some estimates, 60 to 70 percent of the world’s wild fish stocks are overexploited or already collapsed.

• Apex predator fish species such as Bluefin tuna and Pacific swordfish feed at the very top of the food chain, eating as many as 15,000 smaller fish a year to survive. For this reason, human consumption of apex predator fish species has a larger impact, or seafood print, on global fisheries than does eating an equivalent amount of fish lower down the food chain.

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• the concept of food miles can be used to measure how far our food travels from where it is produced to where it is consumed. Higher food miles generally mean a greater environmental impact since more fossil fuels are used in transportation. A local foods movement focused on farmers’ markets and gardening in homes and schools is growing rapidly in response to an awareness of food miles.

critical thinking and Discussion Questions

1. the two commodities of food and energy are both critical in our day-to-day lives. We couldn’t survive without food, and it’s hard to imagine how we’d get by without energy to move our cars, light and heat our homes, and power our economy. It turns out that these two commodities are also very tightly linked. think about a recent meal you consumed and then try to account for all of the ways in which energy was used to get that meal in front of you, going as far back in the production process as possible. What does this say about the environmental impact of agriculture and the security of our food system in an age of unstable energy supplies?

2. Experts disagree over whether continued increases in population will lead to more widespread famine in the future. Some argue that we have already exploited the best lands for agriculture and that green revolution approaches are no lon- ger increasing yields. others suggest that new approaches to agriculture, such as genetic engineering, will increase production enough to avert disaster. Still oth- ers argue that there is more than enough food in the world if people are willing to adjust their diets and, for example, eat less meat. How compelling do you find each of these arguments? What does it suggest to you about what needs to be done to meet our food needs in the future?

3. Agriculture is a persistent and leading cause of water pollution in the united States. In contrast, since the 1960s there has been great progress made in reducing water pollution from large industrial and sewage treatment facilities. What is it about an activity like agriculture that might make it more difficult to control runoff and pollu- tion compared to large industrial facilities?

4. Whether you realize it or not, genetically modified corn, soybeans, and other crops are already present in much of the food you eat. At least in the united States, con- cerns over consumer safety from genetic engineering have not slowed the devel- opment of these products. What kinds of safety research and testing do you think should occur before genetically engineered crops are approved for mass production and human consumption? How might the basic principles of the scientific method be used to design and carry out that research?

5. How is genetic modification different from traditional cross-breeding techniques? What are the ramifications of these differences? consider both intentional results and unintended consequences.

6. Aquaculture, or fish farming, is frequently touted as a more sustainable alterna- tive to seafood production than catching wild fish. Yet not all forms of aquaculture are as sustainable as others. As section 3.4 points out, eating farmed tilapia is more sustainable than eating farmed salmon. Why is this? What is it about the diets of dif- ferent fish species—such as tilapia or salmon—that make the farming of one more sustainable than the other? How might you use that knowledge to build a sustainable aquaculture system?

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agflation  An increase in the price of food that occurs as a result of increased demand from human consumption.

agroecology An ecological approach to agriculture that views agricultural areas as ecosystems and is concerned with the eco- logical impact of agricultural practices.

apex the top or highest part of something.

apex predators Predators that feed at the very top of the food chain.

aquaculture the growing and harvesting of fish and shellfish for human use.

biofuels Gas or liquid fuels made from plant material.

Dust Bowl the ecological and agricultural damage in the American Plains created by the severe dust storms of the 1930s; for more information, visit http://www.pbs .org/wgbh/americanexperience/films /dustbowl.

food miles the measure of how far food travels on average from where it is produced to where it is consumed.

genetic engineering the deliberate modi- fication of the characteristics of an organism by manipulating its genetic material.

Global Food Price Index A measure of the monthly change in international prices of a basket of food commodities, specifically the prices of cereal, oils/fats, sugar, dairy, and meat.

green revolution term for the introduction of scientifically bred or selected varieties of grain that, with adequate inputs of fertilizer and water, can greatly increase crop yields.

locavore one who primarily eats food that is grown or produced within the local com- munity or region.

Malthusian correction theory put forth by the reverend thomas robert Malthus (1766–1834) that population growth is eventually curtailed by famine, disease, or other factors.

monocultures cultivation of a single crop, usually on a large area of land.

seafood print A measure of the amount of primary production—microscopic organ- isms at the bottom of the marine food web— required to make a pound of a given type of fish.

7. the idea of using food miles as a key indicator of the environmental impact of a certain food product has recently come under attack as being oversimplified. crit- ics point out that it’s not just how far a food item travels that determines how much energy is used to bring it to market, but also how much energy is used, and how effi- ciently it’s used, to produce it in the first place. If you had to design an experiment to estimate the life cycle energy costs (how much energy is used in the entire process of producing and transporting a product to market) of an apple grown 1,500 miles away on a large apple farm versus one grown locally by a small farmer, how would you do it? What factors would you want to consider in making this comparison?

Key terms

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Additional resources the following links are useful to learn more about the history, science, and impacts (positive and negative) of the green revolution:

• http://www.ars.usda.gov/is/timeline/green.htm • http://www.ifpri.org/sites/default/files/pubs/pubs/ib/ib11.pdf

Here are a number of very useful sources for understanding the basic concepts behind sus- tainable agriculture, agroecology, and organic agriculture:

• From the u.S. Department of Agriculture: ❍ http://www.nal.usda.gov/afsic/pubs/terms/srb9902.shtml ❍ http://www.nal.usda.gov/afsic/pubs/agnic/susag.shtml ❍ http://afsic.nal.usda.gov/sustainability-agriculture-0 ❍ http://www.ers.usda.gov/amber-waves.aspx

• other useful readings: ❍ http://agroeco.org/socla/wp-content/uploads/2013/12/wezel-agro

ecology.pdf ❍ http://nature.berkeley.edu/~miguel-alt/ ❍ http://www.thesolutionsjournal.com/node/971 ❍ http://cedarcreek.umn.edu/biblio/fulltext/nature10452.pdf ❍ http://e360.yale.edu/feature/the_folly_of_big_agriculture_why

_nature_always_wins/2514/ ❍ http://e360.yale.edu/feature/can_reforming_the_farm_bill_help

_change_us_agriculture/2508/ ❍ http://e360.yale.edu/feature/helping_us_farmers_increase

_production_and_protect_the_land/2549/

not surprisingly, there is a wealth of information on the subject of genetically modified (GM) foods. A good starting point is the noVA/Frontline special report titled Harvest of Fear. Besides basic background information on the concept, the site includes activities that allow you to design your own GM crop.

• http://www.pbs.org/wgbh/harvest/ • http://www.pbs.org/wgbh/harvest/engineer/ • http://www.pbs.org/wgbh/harvest/coming/ • http://www.pbs.org/wgbh/harvest/viewpoints/

other useful sites, stories, and resources on GM crops and the controversies surrounding genetic engineering of foods include the following:

• http://www.nature.com/news/specials/gmcrops/index.html • http://www.nytimes.com/2013/08/25/sunday-review/golden-rice-lifesaver.html • http://grist.org/food/golden-rice-fools-gold-or-golden-opportunity/ • http://www.nytimes.com/2013/07/28/science/a-race-to-save-the-orange-by

-altering-its-dna.html • http://www.michaelspecter.com/wp-content/uploads/pharmageddon.pdf • http://www.elle.com/beauty/health-fitness/allergy-to-genetically-modified-corn • http://www.brown.edu/ce/adult/arise/resources/docs/yw10_1.pdf

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• http://www.who.int/foodsafety/biotech/en/ • http://e360.yale.edu/feature/why_i_still_oppose_genetically_modified_crops/2191/ • http://e360.yale.edu/digest/growing_number_of_pests_developing_resistance_to

_gm_crops/3866/ • http://e360.yale.edu/digest/increase-in-gm-crops-leads-to-jump-in-herbicide

-use/2149/ • http://e360.yale.edu/digest/scientists-find-first-evidence—of-gm-crops-reproducing

-in-the-wild/2538/ • http://e360.yale.edu/digest/genetically-modified-crops-needed-to-avert-food

-crisis-panel-says/2110/ • http://e360.yale.edu/digest/farmer-groups-protest—indias-first-genetically

-modified-food-crop/2168/

Information on the environmental and health impacts of our meat-based diet can be found at the following links:

• http://www.nytimes.com/2008/01/27/weekinreview/27bittman.html?_r=0 • http://www.nytimes.com/imagepages/2008/01/27/weekinreview/20080127

_BIttMAn1_GrAPHIc.html • http://www.nytimes.com/imagepages/2008/01/27/weekinreview/20080127

_BIttMAn2_GrAPHIc.html • http://chartsbin.com/view/bhy • http://www.npr.org/blogs/thesalt/2012/06/26/155720538/the-making-of-meat

-eating-america • http://www.npr.org/blogs/thesalt/2012/06/27/155527365/visualizing-a-nation

-of-meat-eaters • http://www.pewtrusts.org/uploadedFiles/wwwpewtrustsorg/reports/Industrial

_Agriculture/PcIFAP_FInAL.pdf

Information on the concept of food miles, including a number of different ways in which you can measure the food miles of foods you typically consume, can be found here:

• http://www.pbs.org/e2/teachers/teacher_food_miles_project.html • http://www.pbs.org/e2/teachers/teacher_309.html • http://lifecyclesproject.ca/initiatives/food_miles/ • http://blogs.cce.cornell.edu/franklin/agriculture-program/ag-economic-development

/food-miles-tools/ • http://www.fallsbrookcentre.ca/cgi-bin/calculate.pl

Interesting information on the growing interest in urban agriculture can be found here:

• http://afsic.nal.usda.gov/farms-and-community/urban-agriculture • http://www.ruaf.org/node/512 • http://topics.nytimes.com/top/reference/timestopics/subjects/a/agriculture

/urban_agriculture/index.html • http://www.epa.gov/brownfields/urbanag/ • http://auachicago.org • http://environment.nationalgeographic.com/environment/photos/urban-farming/ • http://www.urbanfarming.org

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A 30-minute expert discussion of the future of the world’s fisheries can be found here:

• http://www.npr.org/templates/story/story.php?storyId=6469061

A very interesting Katie couric interview on Americans and food can be found here:

• http://www.youtube.com/watch?v=7prLrgbojZg

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