Environmental Science and Sustainability Chapter 12 PDF

CHAPTER 12 Food: How Do We Feed Ourselves? Copyright © 2023 W. W. Norton & Company, Inc. Chapter 12 Outline 12.1 How Did Our Modern Agriculture Develop? 12.2 How Does Modern Agriculture Impact the Environment? 12.3 How Is Meat Production Changing What We Consume? 12.4 Is Conventional Meat P...

CHAPTER 12 Food: How Do We Feed Ourselves? Copyright © 2023 W. W. Norton & Company, Inc. Chapter 12 Outline 12.1 How Did Our Modern Agriculture Develop? 12.2 How Does Modern Agriculture Impact the Environment? 12.3 How Is Meat Production Changing What We Consume? 12.4 Is Conventional Meat Production Sustainable? 12.5 How Have Our Food Systems Changed? 12.6 How Do Our Food Choices Link to Sustainability? 12.7 What Can I Do? Chapter Objectives: This chapter will help you… explain how human societies came to rely on cultivated plants and domesticated animals for food. identify the environmental impacts associated with modern methods of crop production. describe modern changes in the way livestock and seafood are produced and identify the associated environmental impacts. discuss important trends with food systems such as the scale of farming, the diversity of food resources, and the components of our diet. explain how organic and sustainable agricultural practices differ from conventional agriculture. summarize how our individual food choices can link to sustainable food production. “In dirt is life.”—George Washington Carver More than 800 million people worldwide suffer from hunger and malnutrition. 12.1 How Did Our Modern Agriculture Develop? Until about 10,000 years ago, humans lived in small groups as hunter-gatherers who moved from place to place to find food, limiting the number of humans on Earth. Agriculture, cultivating plants and domesticating animals for consumption, resulted in a larger population and a smaller amount of land needed to support a person. Historical Agricultural Practices (1 of 3) Humans learned how to create domesticated varieties of many crops, such as wheat and corn. Domestication of animals began with dogs for hunting and then animals such as cattle, chicken, and pigs for consumption. Until the 1950s, most farms raised animals as well as crops, which provided sources of manure for fertilizer, muscle power for farm implements, and edible protein such as meat, eggs, and dairy. Modern Agricultural Practices: The Green Revolution New technologies in the twentieth century led to what is known as the “Green Revolution.” After 1960, tripling the average grain yields to 6 metric tons per hectare only took 40 years. Gas- and diesel-powered plows and harvesting equipment replaced human and animal powered tools. This reduced the time and effort required for cultivation, but increased numbers of farm equipment and use of fossil fuels. Modern Irrigation Large-scale dams and reservoirs, electric aquifer pumps, long- distance canals and pipelines, and automated sprinkler systems have allowed the global area of irrigated farmland to increase to 20%. Synthetic Fertilizers and Pesticides Use of synthetic fertilizers and pesticides have increased globally. Synthetic pesticides are industrially produced chemicals applied to combat insects and weeds These pesticides have been found to harm pollinators. 70-100 of the top food crops rely on pollinators. Fertilizers are industrially produced chemicals that have one or more of the primary nutrients for plant growth (N-P-K) Synthetic fertilizers degrade soil and run off in the water, affecting marine life. Soil microbes rapidly convert nitrogen-based fertilizers into N O2 emissions, and N O is 300x more potent as a greenhouse gas than 2 carbon dioxide. Genetic Manipulation Genetic engineering is splicing genetic material from one species into the DNA of another. Genetic engineering has been used to create varieties of genetically modified organisms (GMOs). Plant geneticists cross-bred wheat, corn, and rice to create varieties that thrive with intensive irrigation and fertilization while resisting common diseases. Genetically Modified Organisms GMOs now constitute 88% of corn and 94% of soybean acreage in the United States. “Roundup-ready” crops are GMOs that allow broad-field spraying to control weeds without affecting crops. Studies have shown that GMOs are creating resistant weeds and insects through natural selection. GMOs have been found in human urine and in foods we consume. Take Home Message Humans began the transition from hunter-gatherer to agricultural societies about 10,000 years ago. By cultivating plants and domesticating animals for consumption, humans have been able to expand the carrying capacity of their environment, supporting an increasing population. Modern agricultural technologies like farm machinery, advanced irrigation, synthetic fertilizers and pesticides, and genetic engineer for new crop varieties transformed the way we grow and harvest food. 12.2 How Does Modern Agriculture Impact the Environment? Take Home Message Modern agricultural practices enabled the Green Revolution and increased yields per acre, but also have adverse environmental effects. Synthetic fertilizer can pollute the land, water, and air. Pesticides pose health risks for those who live and work near where they are applied. Pesticides foster resistant pests over time. Reliance on new high-yield crop varieties reduces genetic variety of food producing crops. Ongoing soil loss, degradation, and salinization reduce global food production capacity. 12.5 How Have Our Food Systems Changed? Together, croplands and pastures are now the largest terrestrial biome, covering almost 40% of Earth’s land surface. A food system is the complex web of processes that connect agricultural production to food consumption. The types of crops we consume has decreased tremendously, with about 60% of human plant calories being derived from only three crops—rice, maize, and wheat. Agricultural Production: Increasing Scale and Shrinking Diversity China, India, and the United States together produce more than half of the world's rice and wheat The production of some foods (like meat) are concentrated in the hands of a small number of companies. Over the past 100 years, the varieties of cultivated food crops have declined 90% with more than half of the global varieties having gone extinct. Historically 3,000 plant species were eaten by humans regularly, but only 150 plants are grown on a significant scale. Food Security Global decrease in agrobiodiversity reduces the resilience of our food systems and threatens food security, affordable access to enough nutritious food to maintain dietary needs. The diagram shows the percentage of students who were food insecure between 2011 and 2015 according to institution type. Food Consumption: Increasing the Role of Meat and Processed Foods We consume significantly more meat and processed foods and produce than previous generations and portion sizes have also greatly increased. Processed foods are produced to optimize ease of preparation, consumption, and storage, and often remove fiber but add sweeteners, salt, fats, colors, artificial flavors, and preservatives. Global meat consumption has increased from 38 to 88 pounds per person per year between 1950 and 2010. Shifting Food Culture Sweet and fatty foods are now cheaper and readily available for consistent consumption. With the fast-paced urban lifestyles in today’s world, more people eat convenient processed foods. Take Home Message Global food systems have undergone significant changes in recent decades. The scale of agricultural production has increased while the number of farms, farm jobs, and crop and livestock varieties has decreased. Agricultural operations are concentrated in few geographic areas and in the hands of a few corporations. Typical diets now include more meats and processed foods which are trends linked to a global rise in obesity. These trends are driven by an increasingly fast-paced and mobile lifestyle with more global, industrialized, and large-scale food exchange systems. 12.6 How Do Our Food Choices Link to Sustainability? Sustainable food choices are important. Consumers' food choices are a part of food production systems. Food choices are often associated with an ethical concern, such as with the support of sustainable agriculture practices. The Efficiency Argument: Eating Low on the Food Chain In a food chain or food web, energy is lost as it is transferred between trophic levels. If we eat lower on the food chain, less energy is lost. Vegans and vegetarians argue that eating lower on the food chain has positive environmental impacts. Producing animal-based foods uses more water and causes more greenhouse gas emissions Question 1 Modern-day agriculture __________________________________________. A. uses less pesticides and fertilizer than ancient agriculture B. has increased our ability to obtain more food from the same area C. has permanently increased soil fertility, providing more food from less space D. has rapidly improved soils, allowing new areas to convert to cropland Question 1: Answer Modern-day agriculture __________________________________________. A. promotes reductions in use of pesticides and fertilizers B. has increased our ability to obtain more food from the same area (Correct) C. has permanently increased soil fertility, providing more food from less space D. has rapidly improved soils, allowing new areas to convert to cropland Question 2 Humans use more fresh water for ____________________ than for any other purpose. A. agriculture B. cooking and drinking C. household use D. industries E. producing hydrogen fuel Question 2: Correct Humans use more fresh water for ____________________ than for any other purpose. A. agriculture (Correct) B. cooking and drinking C. household use D. industries E. producing hydrogen fuel Question 3 Leaching ____________________________________________________________. A. is an artificial method to help plant growth B. is caused by movement of water upward through soil from the water table C. adds nutrients from the air to the soil D. removes water-soluble nutrients from topsoil due to crop irrigation E. is a common agricultural practice to improve soil Question 3: Answer Leaching ____________________________________________________________. A. is an artificial method to help plant growth B. is caused by movement of water upward through soil from the water table C. adds nutrients from the air to the soil D. removes water-soluble nutrients from topsoil due to crop irrigation (Correct) E. is a common agricultural practice to improve soil Credits This concludes the Lecture PowerPoint presentation for Environmental Science and Sustainability, Chapter 12, by David Montgomery and Daniel Sherman For more resources, please visit https://digital.wwnorton.com/environsci2 Copyright © 2023 W. W. Norton & Compan y, Inc.