The Environment

In the United States, 80% of agricultural land is utilized to raise animals for food or to grow their feed. Animal-based foods demand more resources, such as land, than plant-based foods do. If crops grown in the United States were directed towards foods for humans, instead of for livestock, they could feed three times more people than today, according to the Institute on the Environment at the University of Minnesota.

Despite common perceptions, meat from grass-fed or pasture-raised cows is less sustainable because it requires more land and resources than conventionally-raised beef does. According to a recent study, if all cows produced today were raised on pasture, available pasture land would only be able to support 27% of the current beef supply.

In 2019, the Brazilian Amazon faced devastating fires caused primarily by massive amounts of land cleared for cattle. Approximately 80% of deforestation in the Amazon Rainforest has been done to clear land for cattle. Today, the number of cows in the Amazon Rainforest has grown to 70-80 million compared to 5 million in the 1960’s. Climate scientists stress the importance of the Amazon because of the vital role it plays in filtering carbon dioxide from the atmosphere. Every year, the Amazon absorbs 2 billion tons of CO2 or 5% of annual human-induced emissions.

During digestion, ruminants such as cattle, sheep, and goats emit methane, an infamous “greenhouse gas” and key contributor to global warming, along with other GHGs including hydrogen sulfide, CO2 and nitrous oxide. These gases trap heat from the sun in the Earth’s atmosphere and warm the planet’s surface. According to NASA, all but one of the warmest years in their 136-year record have happened in the past 20 years and at least 80% of climate scientists agree that humans are causing this global warming.. Animal agriculture contributes about 66% of all agricultural greenhouse gas emissions in the United States.

Raising billions of animals for slaughter each year also means producing an exorbitant amount of waste. Factory farms in the United States produce more than 500 million tons of manure annually according to the EPA. Today, fewer farms are raising more animals and factory farms are spreading manure in concentrated open-air pools, called manure lagoons. Often as big as several football fields, these lagoons are prone to leaks and spills and can devastate nearby lands and communities by polluting the surrounding ecosystems, air, and water. In 2011, an Illinois hog farm spilled 200,000 gallons of manure into a creek, killing more than 110,000 fish.

When lagoons reach capacity, farmers will often opt to apply manure to surrounding areas rather than pay to have the waste transported off-site. According to the USDA, animal waste can contaminate water supplies and emit harmful gases into the atmosphere when over-applied to land.

In order to prevent the spread of disease in the crowded, filthy conditions of confinement operations, and to promote faster growth, producers feed farm animals a number of antibiotics. Upwards of 75 percent of the antibiotics fed to farm animals end up undigested in their urine and manure. Through this waste, the antibiotics may contaminate crops and waterways and ultimately be ingested by humans.

Between watering the crops that farm animals eat, providing drinking water for billions of animals each year, and cleaning away the filth in factory farms, transport trucks, and slaughterhouses, the animal agriculture industry has a huge impact on the water supply. Producing one pound of beef takes an estimated 1,581 gallons of water, which is roughly as much as the average American uses in 100 showers.

Our modern food system has a profound impact on the environment – polluting our land, air, and water; depleting natural resources; and contributing to global climate change. Farm Sanctuary offers a free curriculum for middle and high school teachers, exploring animal agriculture’s effects on our planet and building scientific literacy on environmental phenomena related to our food system.

Sustainable Future Curriculum at a glance:

• Environmentally focused lessons aligned with Next Generation Science Standards
• Lessons follow the 5E Model, encouraging students to learn through engagement and exploration
• Within each lesson, you’ll find an Overview, Essential Question(s), Lesson Time, Student Learning Objectives, Resources, Materials, and Next Generation Science Standards
• References include the CDC, EPA, FAO, NASA, NRDC, USDA, and more
• Designed in consultation with expert advisor Jennifer Ayla Jay, Ph.D., Professor, UCLA Civil and Environmental Engineering

Global Warming & Our Food System:
A Greenhouse Effect Inquiry Lab

Lesson Time
Section 1: 60–75 minutes
Section 2: 60–75 minutes

Overview

The surface of the earth is warmed by the sun’s radiation. Greenhouse gases in the atmosphere of the Earth “trap” some of this radiation that would otherwise be released back into space, warming the planet. This is known as the greenhouse effect. Without the greenhouse effect, there would be no life on earth.

• Students will develop a model to explore how the greenhouse effect works in an inquiry-based laboratory activity.
• Students will differentiate between the greenhouse effect, global warming, and climate change.
• Students will also investigate some of the factors that are increasing greenhouse gas emissions and resulting in global climate change such as clearing land for agriculture and raising animals for food.

Environmental Impacts & Our Food System:
Exploring the Evidence

Lesson Time
Section 1: 60–75 minutes
Section 2: 60–75 minutes

Overview

Modern animal agriculture has a pronounced impact on natural resources like land, water, and fossil fuel. Industrialized agriculture or factory farms, along with small farms, produce significant amounts of waste and are inextricably connected to the scale at which humans are able to raise billions of animals each year for food. The sheer number of animals raised for food has sparked concerns about animal agriculture, including the magnitude to which it is polluting our land, air, and water as well as contributing to global climate change.

• For this activity, students will learn how the volume and scale of modern animal agriculture is connected to pollution, depletion, and degradation of natural resources and global climate change.
• Students in small groups will construct an argument supported by evidence that explores a phenomenon related to animal agriculture and the environment.

Food Production & CO2 Equivalents:
Creating a Computational Simulation

Lesson Time
Section 1: 50 minutes
Section 2: 50 minutes
Section 3: 50 minutes

Overview

Global warming can be attributed to an increase in greenhouse gas production. Many people assume that this increase primarily results from the burning of fossil fuels, for instance from cars, but the agricultural industry is actually a major contributor. In this lesson, students will compare the carbon footprint of different types of foods to explore where greenhouse gases are coming from and which foods produce the most emissions.

• Students will use carbon dioxide equivalents (CO2e) to compare the amount of greenhouse gases released from different processes during food production.
• Students will use a spreadsheet to graph data in order to compare the CO2e for plant-based and animal-based food production.
• Students will then use a formula to calculate the number of miles driven by a typical car for 1 kg of different types of food.

Animal Agriculture & the Environment:
Creating a Computational Representation

Lesson Time
Section 1: 50 minutes
Section 2: 50 minutes
Section 3: 50 minutes
Section 4: 50 minutes

Overview

For this activity, students will learn how computational representations are used to simplify mathematical relationships. Students will research and gather data on the impact that the rise in industrialized farming has on the environment and the far-reaching consequences that animal agriculture has on humans. Students will use these data to create an infographic, a format that uses computational representations in order to visually explain a topic.

• Students will explore different types of infographics and methods for graphically representing data.
• Students will develop a claim based on their research of a topic related to animal agriculture and its effects on humans and the environment.
• Students will locate data that supports their claim and express it graphically, creating at least three computational representations (through pie charts, bar graphs, etc.).