AP Environmental Science - 10&11

Some economists maintain that private ownership can prevent the tragedy of the commons.

- After all, a landowner is much less likely to overgraze his own land than he would common land. - Governmental regulation is another approach. For example, a local government could prevent overuse of a common pasture by passing an ordinance that permits only a certain number of sheep to graze there.

GMO seed crops can increase farm profits in two ways.

- Although GMO crop seeds do cost more to purchase than conventional crop seeds, they reduce pesticide use, which can be a significant savings. - GMO crops can also raise revenues by producing greater yields. - Both of these changes can lead to higher incomes for farmers, lower food prices for consumers, or both.

monocropping

- Both the mechanization of agriculture and the use of synthetic fertilizers encourage large plantings of a single species or variety, a practice known as monocropping - is the dominant agricultural practice in the United States, where corn, soybean, wheat, and cotton are frequently grown in monocrops of 405 ha (1,000 acres) or more

Create a range of housing opportunities and choices.

- By providing housing for people of all income levels, smart growth counters the concentration of poverty in failing urban neighborhoods. - Mixed housing also allows more people to find jobs near where they live, improves schools, and generates strong support for neighborhood transit stops, commercial centers, and other services.

Many environmental scientists argue that rangeland ecosystems are too fragile for multiple uses.

- Certain environmental organizations have suggested that as much as 55 percent of U.S. rangeland soils are in poor or very poor condition, due in large part to overgrazing. - However, the BLM, which manages most public rangelands in the United States, has maintained that the percentage of poor or very poor soils is not nearly that high. - Reconciling this difference is a challenge because of the many factors that influence how soil condition is determined.

The federal government has also played a large part in encouraging the growth of suburbs through the Federal Housing Administration (FHA).

- Congress established the FHA during the Great Depression of the 1930s, in part to jump-start the economy by creating more demand for new housing. - Through the FHA, people could apply for federally subsidized mortgages that offered low interest rates, which allowed many people who otherwise could not afford a house to purchase one. - However, the FHA financed mortgages only for homes in financially "low risk" areas that were almost always the newly built, low-density suburbs. - At the end of World War II, the GI Bill extended generous credit terms to war veterans, and the suburban housing boom continued. - Suburbs became even more attractive as cars became more affordable and mass-produced housing allowed developers to sell suburban homes at affordable prices.

Since 1982, federal regulations have required the USFS to provide appropriate habitat for plant and animal communities while at the same time meeting multiple-use goals.

- However, because these regulations fail to specify how biodiversity protection should be achieved or how the results should be quantified, the USFS has had to choose its own approach to biodiversity management. - Critics charge that the USFS is not adequately protecting biodiversity and forest ecosystems, but the USFS maintains that it is doing the best it can at meeting many different objectives.

Concerns about genetic engineering

- However, many European countries, as well as a number of people in the United States, question the safety of GMOs. - Genetically modified crops and livestock are the source of considerable controversy, and concerns have been raised about their safety for human consumption and their effects on biodiversity. - Regulation of GMOs is also an issue, both in the United States and abroad.

The environmental impact of selective cutting is less extensive than that of clear-cutting

- However, many of the negative environmental impacts associated with logging remain the same. - For example, whether a company uses clear-cutting or selective cutting, it will need to construct logging roads to carry equipment and workers into the area that will be harvested. - These roads fragment the forest habitat, which affects species diversity, and compact the soil, which causes nutrient loss and reductions in water infiltration.

he application of pesticides allows a farmer to quickly and relatively easily respond to an infestation of pests on an agricultural crop.

- In many cases, a single application can significantly reduce a pest population. - By preventing crop damage, pesticide application can result in greater crop yields on less land, thereby reducing the area disturbed by agriculture and making agriculture more efficient.

Genetic engineering can increase food production in several ways

- It can create strains of organisms that are resistant to pests and harsh environmental conditions such as drought or high salinity. - In addition, agricultural scientists have begun to engineer plants that produce essential nutrients for humans.

The Taylor Grazing Act of 1934 was passed to halt overgrazing.

- It converted federal rangelands from a commons into a permit-based grazing system. - The goal of a permit-based system is to limit the number of animals grazing in a particular area and thereby avoid a tragedy of the commons situation. - However, critics maintain that the low cost of the permits continues to encourage overgrazing. - For decades, the federal government has spent seven times more money managing its rangelands than it has received in permit fees. - Thus, in effect, grazing is subsidized with federal funds.

Make development decisions predictable, fair, and cost-effective.

- Suburban developments throughout the country often look the same because standardized designs allow developers to move rapidly through the permitting process. - A streamlined approval process that encourages smart growth could increase the number of individualized plans rather than promoting cookie-cutter development.

energy subsidy

- The fossil fuel energy and human energy input per calorie of food produced, beyond that which is provided by the sun

Selctive cutting

- removes single trees or a relatively small number of trees from the larger forest. - This method creates many small openings in a stand where trees can reseed or young trees can be planted, so the regenerated stand contains trees of different ages. - Because seedlings and young trees must grow next to larger, older trees, selective cutting produces optimum growth only among shade-tolerant tree species.

Forests affect the atmosphere via:

1. Amount of sunlight reflected/absorbed (What is this called?) 2. Water transfer 3. Rate of greenhouse gas (CO2 ) release (equation for photosynthesis) 4. Altering surface wind speeds

pesticide treadmill

A cycle of pesticide development, followed by pest resistance, followed by new pesticide development.

desertification

The transformation of arable, productive land to desert or unproductive land due to climate change or destructive land use.

Endangered Species Act

a 1973 law designed to protect species from extinction.

intercropping

in which two or more crop species are planted in the same field at the same time to promote a synergistic interaction between them.

broad-spectrum pesticides

meaning that they kill many different types of pest

persistent pesticides

meaning that they remain in the environment for years to decades

contour plowing

plowing and harvesting parallel to the topographic contours of the land—helps prevent erosion by water while still allowing for the practical advantages of plowing

environmental mitigation plan

stating how it will address the project's environmental impact.

herbicides

target plant species that compete with crop

More than 95 percent of all federal lands are managed by four federal agencies:

the Bureau of Land Management (BLM), the United States Forest Service (USFS), the National Park Service (NPS), and the Fish and Wildlife Service (FWS). BLM, USFS, and NPS lands are typically classified as multiple-use lands because most, and sometimes all, public uses are allowed on them.

fishery collapse

the decline of a fish population by 90 percent or more is referred to as

aquaculture

which is the farming of aquatic organisms such as fish, shellfish, and seaweeds

economies of scales

which means that the average costs of production fall as output increases

FWS land

wildlife conservation, hunting, and recreation

Forests affect

• Soils, water supplies, habitat availability, global chemical and climate cycles, recreation, and aesthetics • Forests slow down erosion and moderate water availability.

rangelands

- are dry, open grasslands primarily used for grazing cattle, which is the most common use of land in the United States. - Rangelands are semiarid ecosystems and are therefore particularly susceptible to fires and other environmental disturbances. - When overused, rangelands can easily lose biodiversity.

food security

- as the condition in which people have access to sufficient, safe, and nutritious food that meets their dietary needs for an active and healthy life. - Access refers to the economic, social, and physical availability of food

irrigation

- can increase crop growth rates or even enable crops to grow where they could not otherwise be grown - For example, irrigation has transformed approximately 400,000 ha (1 million acres) of former desert in the Imperial Valley of southeastern California into a major producer of fruits and vegetables. - In other situations, irrigation can allow productive land to become extremely productive land. - One estimate suggests that the 16 percent of the world's agricultural land that is irrigated produces 40 percent of the world's food.

A Sand County Almanac by Aldo Leopold

- characterizes land management, conservation, ecology, and interactions with people that in a way that was pioneering when published, and is still timely and important today. - Leopold wrote about a "land ethic," which he described as a moral responsibility of humans to the natural world. - The moral responsibility to protect land is not typically a topic in environmental science, but many contemporary discussions about the conservation and protection of public and private lands inevitably reference Aldo Leopold.

Before a project can begin, NEPA rules require the project's developers to file an environmental impact statement.

- environmental impact statement (EIS) typically outlines the scope and purpose of the project, describes the environmental context, suggests alternative approaches to the project, and analyzes the environmental impact of each alternative. - NEPA does not require that developers proceed in the way that will have the least environmental impact. - However, in some situations, NEPA rules may stipulate that building permits or government funds be withheld until the developer submits an environmental mitigation plan stating how it will address the project's environmental impact. - In addition, preparation of the EIS sometimes uncovers the presence of endangered species in the area under consideration. - When this occurs, managers must apply the protection measures of the Endangered Species Act, a 1973 law designed to protect species from extinction.

Sustainable agriculture

- fulfills the need for food and fiber while enhancing the quality of the soil, minimizing the use of nonrenewable resources, and allowing economic viability for the farmer. - It emphasizes the ability to continue agriculture on a given piece of land indefinitely through conservation and soil improvement. - Sustainable agriculture often requires more labor than industrial agriculture, which makes it more expensive in places where labor costs are high. - But practitioners of sustainable agriculture consider the improved long-term productivity of the land to be worth this extra cost.

shifting agriculture

- in which the land is cleared, the vegetation is burned, and the land is used for only a few years until the soil is depleted of nutrients. - This traditional method of agriculture uses a technique sometimes called "slash-and-burn," in which existing trees and vegetation are cut down, placed in piles, and burned - The resulting ash is rich in potassium, calcium, and magnesium, which make the soil more fertile, although these nutrients are usually depleted quickly. - If the deforestation occurs in an area of heavy rainfall, nutrients may be washed away, along with some of the soil, which further reduces the availability of nutrients. - After a few years, the farmer usually moves on to another plot and repeats the process.

famine

- is a condition in which food insecurity is so extreme that large numbers of deaths occur in a given area over a relatively short period. - Actual definitions of famine vary widely depending on the agency using the term. - One relief agency defines a famine as an event in which there are more than five deaths per day per 10,000 people due to lack of food. - According to this definition, there is an annual mortality rate of 18 percent during a famine. - Famines are often the result of crop failures, sometimes due to drought, although famines can also have social and political causes.

undernutrition

- means not consuming enough calories to be healthy. Food calories are converted into usable energy by the human body. - Not receiving enough food calories leads to an energy deficit. - An average person needs approximately 2,000 kilocalories per day, though this amount varies with gender, age, and weight. - A long-term food deficit of only 100 to 400 kilocalories per day—in other words, an intake of 100 to 400 kilocalories less than one's daily need—deprives a person of the energy - needed to perform daily activities and makes the person more susceptible to disease. - In children, undernutrition can lead to improper brain development and lower IQ.

ecologically sustainable forestry

- removes trees from the forest in ways that do not unduly affect the viability of other, noncommercial tree species. - This approach has a goal of maintaining both plants and animals in as close to a natural state as possible. - Some loggers have even returned to using animals such as horses to pull logs in an attempt to reduce soil compaction. - However, the costs of such methods make it difficult to compete economically with mechanized logging practices

urban sprawl

- urbanized areas that spread into rural areas and remove clear boundaries between the two. - The landscape in these areas is characterized by clusters of housing, retail shops, and office parks, which are separated by miles of road. - Large feeder roads and parking lots that separate "big box" and other retail stores from the road discourage pedestrian traffic.

The 2014 United Nations List of Protected Areas classifies protected public lands into six categories according to how they are used:

National parks, managed resource protected areas, habitat/species management areas, strict nature reserves and wilderness areas, protected landscapes and seascapes, and national monuments.

suburbs

are areas that surround metropolitan centers and have low population densities compared with urban areas

exurbs

are similar to suburbs, but are not connected to any central city or densely populated area.

smart growth

focuses on strategies that encourage the development of sustainable, healthy communities.

BLM land

grazing, mining, timber harvesting, and recreation

induced demand

in which an increase in the supply of a good causes demand to grow.

fishery

is a commercially harvestable population of fish within a particular ecological region

perennial plants

live for multiple years, and there is usually no need to disturb the soil

NPS land

recreation and conservation

food insecurity

refers to the condition in which people do not have adequate access to food

selective pesticides or narrow-spectrum pesticides

target a narrow range of organisms

Insecticides

target species of insects and other invertebrates that consume crops

urban blight

the degradation of the built and social environments of the city that often accompanies and accelerates migration to the suburbs.

USFS land

timber harvesting, grazing, and recreation

negative externality

tragedy of the commons is the result of an economic phenomenon called a ___

Each tree occupies its own niche through varying tolerances to and requirements for:

• Moisture • Shade/sunlight • Soil structure • Disturbance

anemia

- is the most widespread nutritional deficiency in the world. - The WHO estimates that there are 2 billion anemic people in the world—many in developing countries, but some in developed countries as well. - Lack of dietary iron is the major cause of anemia, but there are other causes, including malaria, AIDS, and parasite infestations. - An increase in the ingestion of iron-rich foods, such as certain grains, herbs, vegetables, and meats, can reduce anemia.

National Environmental Policy Act (NEPA)

- mandates an environmental assessment of all projects involving federal money or federal permits. - Along with other major laws of the 1960s and 1970s, such as the Clean Air Act, the Clean Water Act, and the Endangered Species Act, NEPA creates an environmental regulatory process designed to ensure protection of the nation's resources.

annual plants

- such as wheat and corn, live only one season and must be replanted each year. - Conventional agriculture of annual plants therefore relies on plowing and tilling, processes that physically turn the soil upside down and push crop residues under the topsoil, thereby killing weeds and insect pupae.

Preserve open space, farmland, natural beauty, and critical environmental areas.

- Working farmland is a source of fresh local produce and other goods. - Open space provides opportunities for recreation and enjoyment. - Land protected from development through restricted growth also provides habitats for a variety of species.

Bycatch

The unintentional catch of nontarget species while fishing.

soil compaction

- A process where repeated trampling by humans, machinery, or animals causes a compaction of soil and a reduction in pore space. - This can result in a decrease in permeability. - When this happens, soil productivity can decrease rapidly, leaving the land suitable only for animal grazing. - In addition, the burning process oxidizes carbon, meaning that it converts it into the oxide compounds carbon monoxide (CO) and carbon dioxide (CO2). - In this way, carbon from the vegetation and the soil is released into the atmosphere and ultimately contributes to higher atmospheric CO2 concentrations.

Foster distinctive, attractive communities with a strong sense of place.

- A sense of place is the feeling that an area has a distinct and meaningful character. - Many cities have such unique neighborhoods. - For example, the French Quarter of New Orleans has a sense of place that adds to the quality of life for people living there. - Smart growth attempts to foster this sense of place through development that fits into the neighborhood.

pesticide resistance

- A trait possessed by certain individuals that are exposed to a pesticide and survive. - If the pesticide is successful in reducing the pest population, the next generation will contain a larger fraction of pesticide resistant individuals in the population. - As time goes by, resistant individuals will make up a larger and larger portion of the population. - Often the resistance becomes more effective, which makes the pesticide significantly less useful.

tragedy of the commons example

- Consider land as an example. Imagine a communal pasture on which many farmers graze their sheep - At first, no single farmer appears to have too many sheep. - But because an individual farmer gains from raising as many sheep as possible, each farmer may be tempted to add sheep to the pasture. - However, if the total number of sheep owned by all the farmers continues to grow, the number of sheep will soon exceed the carrying capacity of the land. - The sheep will overgraze the pasture to the point at which plants will not have a chance to recover. - The common land will be degraded and the sheep will no longer have an adequate source of nourishment. - Over a longer period, the entire community will suffer. - When the farmers make decisions that benefit only their own short-term gain and do not consider the common good, eventually, everybody loses. - That is why it is called a "tragedy"—there are no winners.

The Environmental Protection Agency lists 10 basic principles of smart growth:

- Create mixed land uses - Create a range of housing opportunities and choices - Create walkable neighborhoods - Encourage community and stakeholder collaboration in development decisions - Take advantage of compact building design - Foster distinctive, attractive communities with a strong sense of place. - Preserve open space, farmland, natural beauty, and critical environmental areas - Provide a variety of transportation choices - Strengthen and direct development toward existing communities. - Make development decisions predictable, fair, and cost-effective.

Crop rotation and the use of pest-resistant crop varieties prevent pest infestations

- Crop rotation can reduce the success of insect pests that are specific to one crop and may have laid eggs in the soil. - When the eggs hatch, if a different crop is present, the crop-specific pest will not have a suitable host and will die. - In the same way, crop rotation can also hinder crop-specific diseases that may survive on infected plant material from the previous season. Intercropping, as stated earlier, also makes it harder for specialized pests that succeed best with only one crop present to establish themselves.

There are also many instances where human behavior and mismanagement can lead to large fires on public or private land.

- Deliberate and accidental fire setting by individuals is certainly a cause of fires. - But poor equipment management may also lead to fires. - The 2017 northern California wildfires attained great attention because of the number, extent, and location in and near Sonoma County, famous for its wine making. - Downed power lines are the suspected cause of some of the 2017 California fires.

Urban sprawl has had a dramatic environmental impact.

- Dependence on the automobile causes suburban residents to drive more than twice as much as people who live in cities. - Between 1950 and 2000, the number of vehicle miles traveled per person in U.S. suburban areas tripled. - Because suburban house lots tend to be significantly larger than their urban counterparts, suburban communities also use more than twice as much land per person as urban communities. - Urban sprawl tends to occur at the edge of a city, often replacing farmland and increasing the distance between farms and consumers. - In its most recent survey, the U.S. Department of Agriculture estimated that between 1982 and 2007, U.S. farmland was being converted to residential uses at a rate of 405,000 ha (1 million acres) per year. - There are four main causes of urban sprawl in the United States: automobiles and highway construction, living costs, urban blight, and government policies.

Strengthen and direct development toward existing communities.

- Development strategies can help to reinvigorate urban neighborhoods that are caught in a vicious cycle of depopulation and blight and can protect rural lands from sprawl. - Development that fills in vacant lots within existing communities, rather than expanding into new land outside the city, is known as infill. - Some cities, such as Portland, Oregon, have had success with urban growth boundaries, which place restrictions on development outside a designated area.

Clear-cutting, especially on slopes, increases wind and water erosion, which causes the loss of soil and nutrients

- Erosion also adds silt and sediment to nearby streams, which harms aquatic populations. In addition, the denuded slopes are prone to dangerous mudslides - Clear-cutting also increases the amount of sunlight that reaches rivers and streams, which raises water temperatures that can adversely affect certain aquatic species. - Even the replanting process can have negative environmental consequences. - Timber companies often use fire or herbicides to remove bushy vegetation before a clear-cut is replanted. - These practices reduce soil quality, and herbicides may contaminate water that runs off into streams and rivers. - Many environmental scientists identify clear-cutting as a cause of habitat alteration and destruction as well as forest fragmentation. - These effects decrease biodiversity and sometimes lower the aesthetic value of the affected forest. - However, in heavily forested regions of the country, such as the northern New England states of Maine, New Hampshire, and Vermont, where forests can cover up to 85 percent of land area, a case can be made that clear-cuts actually increase habitat diversity and, as a result, species diversity.

Plowing and tilling exert a number of negative impacts on soils.

- Every time soil is plowed or tilled, soil particles that were attached to other soil particles or to plant roots are disturbed and broken apart and become more susceptible to erosion. - Soil below the plow zone may become susceptible to compaction. - In addition, repeated plowing increases the exposure of organic matter deep in the soil to oxygen. - This exposure leads to oxidation of organic matter, a reduction in the organic matter content of the soil, and an increase in atmospheric CO2 concentrations. - Plowing and tilling, in addition to irrigation and overuse of cropland, have led to severe soil degradation in many parts of the world

Like most human activities, grazing livestock has mixed environmental effects.

- Grazing livestock on open lands uses much less fossil fuel energy than raising them in feedlots. - Furthermore, grazing domesticated animals for short, intense periods of time can mimic the pressure on grasslands that have been experienced over evolutionary time by migrating herds of bison and other herbivores. - Therefore, the grazing of livestock can help maintain grasslands and prevent less desirable species from becoming dominant. - In addition, grazing introduces animal waste and aerates the soil, both of which are beneficial to ecosystems. - However, improperly managed livestock can damage stream banks and pollute surface waters. - Grazing too many animals in a finite area can quickly denude a region of vegetation - Overgrazed land is exposed to wind erosion which makes it difficult for soils to absorb and retain water and nutrients when it rains.

Mechanization

- Farming involves many kinds of work. - Fields must be plowed, planted, irrigated, weeded, protected from pests, harvested, and prepared for the next season. - After harvesting, crops must be dried, sorted, cleaned, and prepared for market in almost as many different ways as there are different crops. - Machines do not necessarily do this work better than humans or animals, but it can be economically advantageous to replace humans or animals with machinery, particularly if fossil fuels are abundant, fuel prices are relatively low, and labor prices are relatively high. In developed countries, where wages are relatively high, less than 5 percent of the workforce works in agriculture. - In developing countries, where wages tend to be much lower, 40 to 75 percent of the working population is employed in agriculture - Since the advent of mechanization, large farms producing staple crops such as beans or corn have generally been more profitable than small farms. - Size matters because of economies of scale - Mechanization also means that single-crop farms are generally more efficient than farms that grow many crops. Because mechanized crop planting and picking require specialized, expensive equipment specific to each crop, planting and harvesting only a single type of crop reduces equipment costs.

In reality, though, there are two problems with using MSY in environmental policy management.

- First, it is very difficult to calculate MSY with certainty because in a natural ecosystem, it is difficult to obtain necessary information such as birth rates, death rates, and the carrying capacity of the system. - Once an MSY calculation is made, we cannot know if a yield is truly sustainable until years later when we can evaluate the effect of the harvest on reproduction. - By that time, if the harvest rate has been too great, it is too late to prevent harm to the population. - In addition to the calculation difficulties, a sizeable group of environmental scientists argue that MSY is not an adequate guide to use for environmental protection. - They believe that unmeasured externalities and harm to ecosystems can occur when using MSY as a harvest guideline, and that the best way to protect the environment is to harvest considerably less than the MSY.

Despite the benefits of increased efficiency and productivity, monocropping can lead to environmental degradation.

- First, soil erosion can become a problem. - Because fields that are monocropped are readied for planting or harvesting all at once, soil will be exposed over many hectares at the same time. - On a 405-ha (1,000-acre) field that has not yet been planted, wind can blow for over 1.6 km (1 mile) without encountering anything but bare soil. - Under these circumstances, the wind can gain enough speed to carry dry soil away from the field. - Certain farmland in the United States loses an average of 1 metric ton of topsoil per hectare (2.5 metric tons per acre) per year to wind erosion.

Smart growth can have important environmental benefits.

- For example, compact development reduces the amount of impervious surface, and allows room for more trees to be planted, both of which reduce runoff and flooding downstream. - A 2000 study found that smart growth in New Jersey would reduce water pollution by 40 percent compared with the more common, dispersed growth pattern. - By mixing uses and providing transportation options, smart growth also reduces fossil fuel consumption. - A 2005 study in Seattle found that residents of neighborhoods incorporating just a few of the techniques to make non-auto travel more convenient traveled 26 percent fewer vehicle miles than residents of more dispersed, less-connected neighborhoods. - A 2012 San Francisco State University study found that similar smart growth practices led to a 20 percent reduction in miles traveled in 18 urban areas across the United States.

In environmental science, we are especially concerned with negative externalities because they so often lead to serious environmental damage for which no one is held legally, financially, or morally responsible.

- For example, if one farmer grazes more sheep than is beneficial for the community in a common pasture, his action will ultimately result in more total harm than total benefit. - But, as long as the land continues to support grazing, the individual farmer will not have to pay for his overuse. - Ultimately, though, other farmers will bear the burden of his overuse because the land will be depleted and they will have to find somewhere else to graze their sheep, or go out of business. - But what if the farmer responsible for the extra sheep had to pay an extra fee for using more of the common resource? - He probably would not graze the extra sheep on the commons because the cost of doing so would exceed the benefit. - From this example, we can see that in order to calculate the true cost of using a resource, we must always include any negative externalities. - In other words, we must account for any potential external harm that comes from the use of that resource.

The BLM focuses on mitigating the damage caused by grazing and considers "rangeland health" when it sets grazing guidelines.

- For example, state and regional rangeland managers are required to ensure healthy watersheds, maintain ecological processes such as nutrient cycles and energy flow, preserve water quality, maintain or restore habitats, and protect endangered species. - However, because these managers are not given detailed guidance, and the BLM regulations do not require the involvement of environmental scientists, the managers have wide latitude to set their own guidelines and standards. - As a result, BLM managers are not consistently successful in preserving vulnerable rangeland ecosystems.

The tragedy of the commons applies not only to agriculture, but to any publicly available resource that is not regulated, including land, air, and water.

- For example, the use of global fisheries as commons has led to the overexploitation and rapid decline of many commercially harvested fish species, and has upset the balance of entire marine ecosystems. - The release of carbon dioxide to the atmosphere or sewage to an estuary are other examples of the tragedy of the commons

benefits of genetic engineering

- Genetically modified crops and livestock offer the possibility of greater yield and food quality, reductions in pesticide use, and higher profits for the agribusinesses that use them. - They are also seen as a way to help reduce world hunger by increasing food production and reducing losses to pests and varying environmental conditions.

fertilizers

- Growing crops and exporting them from the farm system to humans for consumption removes organic matter and nutrients from soil. - If these materials are not replenished, they can be quickly depleted. - Industrial agriculture, because it keeps soil in constant production, requires large amounts of fertilizers to replace lost organic matter and nutrients. - Fertilizers contain essential nutrients for plants—primarily nitrogen, phosphorus, and potassium—and they foster plant growth where one or more of these nutrients is lacking. - There are two types of fertilizers used in agriculture: organic and synthetic.

This concept is referred to as "eating lower on the food chain."

- It was made popular in the United States in a book called Diet for A Small Planet by Frances Moore Lappé in 1971. - The main premise is that human beings can utilize fewer calories from agriculture and obtain sufficient nutrition (protein, vitamins, and calories) by eating primary producers (plants) rather than primary consumers (animals). - This process is called "eating lower on the food chain" because primary producers are one level lower on the trophic pyramid than primary consumers such as chickens, pigs, and cows. - The book also publicized the fact that with proper attention to food choices, one can obtain sufficient protein from plants.

Monocropping also makes crops more vulnerable to attack by pests.

- Large expanses of a single plant species represent a vast food supply for any pests that specialize on that particular plant. - Such pests will establish themselves in the monocrop and reproduce rapidly. - Their populations may experience exponential growth similar to what we saw in Georgii Gause's Paramecium populations that were supplied with unlimited food - Natural predators may not be able to respond rapidly to the exploding pest population. - Many predators of crop pests, such as ladybugs and parasitic wasps, are attracted to the pests that feed on monocrops. - But these predators also rely on non-crop plants for habitat, which monocropping removes. - Therefore, predators that might otherwise control the pest population are largely absent.

Forest trees, like animal populations, have a maximum sustainable yield.

- Loggers may remove a particular percentage of the trees at a site in order to allow a certain amount of light to penetrate to the forest floor and reach younger trees. - If they cut too many trees, however, an excess of sunlight will penetrate and dry the forest soil. - This drying may create conditions inhospitable to tree germination and growth, thus inhibiting adequate regeneration of the forest. - In theory, harvesting the maximum sustainable yield should permit an indefinite use without depletion of the resource.

National parks

- Managed for scientific, educational, and recreational use, and sometimes for their beauty or unique landforms. - In most cases, they are not used for the extraction of resources such as timber or ore. - Some of the most famous national parks in the United States are Yellowstone, Yosemite, Grand Canyon, Acadia, and Great Smoky Mountains - Some of the best known are in Africa and include Amboseli National Park in Kenya, Serengeti National Park in Tanzania, and Kruger National Park in South Africa. - These parks generally exist to protect animal species such as elephants, rhinoceroses, and lions, as well as areas of great natural beauty. - They also generate tourism, which can provide revenue to local and national economies. - Even though national parks in the United States are not used for resource extraction, there still may be some level of management permitted or desired. - For example, controlled burns may be deliberately introduced to remove deadwood in the understory of a forest and thereby reduce the risk of a catastrophic wildfire.

National Momuments

- National monuments are set aside to protect unique sites of special natural or cultural interest. - There are thousands of national monuments and landmarks around the world. - Most of these are established to protect historical landmarks, such as the Arc de Triomphe in Paris, France, or to identify areas of natural beauty and historical and cultural importance, such as Bears Ears National Monument in Utah in the United States - Designation of protected areas typically generates great benefits for the natural environment and plant and animal species. - On the negative side, in order to create and maintain protected areas, governments have sometimes evicted and excluded indigenous human populations from the land, creating humanitarian crises. - For example, in the winter of 2009, a series of evictions from the Mau Forest in the Rift Valley of Kenya led to the displacement of 20,000 families. - One of the leading Kenyan newspapers reported that 2,300 families had not been resettled by 2015. Such programs continue to generate controversy in Kenya and other countries.

prescribed burns

- One method for reducing the accumulation of dead biomass is a prescribed burn, in which a fire is deliberately set under controlled conditions in order to reduce the accumulation of dead biomass on a forest floor. - Prescribed burns help reduce the risk of uncontrolled natural fires and provide some of the other benefits of fire. - More recently, forest managers have allowed certain fires that have occurred naturally to burn. - This policy appears to have been accepted in many parts of the United States, as long as human life and property are not threatened.

Challenging the idea that government regulation is necessary, the late Professor Elinor Ostrom (1933-2012) of Indiana University showed that many commonly held resources can be managed effectively at the community level or by user institutions.

- Ostrom's work, for which she was awarded the 2009 Nobel Prize in Economics, has shown that self-regulation by resource users can prevent the tragedy of the commons. - Professor Ostrom also challenged the idea that private property rights can address all environmental problems.

multiple use lands

- Public lands that are classified as multiple-use lands might be used for a variety of purposes at the same time, including recreation, grazing, timber harvesting, and mineral extraction. - Other areas are designated as protected lands in order to maintain a watershed, preserve wildlife and fish populations, or maintain sites of scenic, scientific, and historical value.

Take advantage of compact building design.

- Smart growth incorporates multistory buildings and parking garages—as opposed to sprawling parking lots—to reduce a neighborhood's environmental footprint and protect more open space. - Ideally, shops, cafés, and small businesses should be easily accessible to pedestrian traffic on the ground floor near sidewalks, with two or three stories of apartments and offices above.

Create mixed land uses

- Smart growth mixes residential, retail, educational, recreational, and business land uses. - Mixed-use development allows people to walk or bicycle to various destinations and encourages pedestrians to be in a neighborhood at all times of the day, increasing safety and interpersonal interactions.

safety of human consumption

- Some people are concerned that the ingestion of genetically modified foods may be harmful to humans, although so far there is little evidence to support these concerns. - However, researchers are studying the possibility that GMOs may cause allergic reactions when people eat a food containing genes transferred from another food to which they are allergic.

Zoning often regulates much more than land use.

- The number of parking spaces a building must have, how far from the street a building must be placed, or even the size and location of a home's driveway are among the development features that zoning may stipulate. - Zoning laws have been helpful in addressing issues of safety and sometimes in minimizing environmental damage caused by new construction. - One negative aspect of zoning, however, is that it generally prohibits suburban neighborhoods from developing a traditional "Main Street" with shops, apartments, houses, and businesses clustered together. - Many communities are now attempting to incorporate multi-use zoning, which allows retail and high-density residential development to coexist in the same area. - However, most zoning in the United States continues to promote automobile-dependent development.

nomadic grazing

- The only sustainable way for people to use soil types with very low productivity is nomadic grazing, in which they move herds of animals, often over long distances, to seasonally productive feeding grounds. - If grazing animals move from region to region without lingering in any one place for too long, the vegetation can usually regenerate.

Despite these advantages, synthetic fertilizers can have several adverse effects on the environment.

- The process of manufacturing synthetic fertilizers uses large quantities of fossil fuel energy. - Producing nitrogen fertilizer is an especially energy-intensive process. - Whereas synthetic fertilizers are more readily available for plant uptake than are organic fertilizers, they are also more likely to be carried by runoff into adjacent waterways and aquifers. - In surface waters, this nutrient runoff can cause algae and other organisms to proliferate. - After these organisms die, they decompose and reduce oxygen levels in the water - synthetic fertilizers do not add organic matter to the soil, as organic fertilizers do

Political and economic factors can be both the cause and effect of undernutrition and malnutrition.

- There are numerous examples in modern history where the lack of an adequate food supply has led to political unrest because people without the means to feed themselves or their families may resort to political protest or violence in an attempt to improve their situation. - A rise in food prices in 2008 led to food riots in Haiti, Egypt, Ivory Coast, Cameroon, Yemen, and elsewhere. Poor governance can create food shortages. - For example, food shortages caused by government agricultural policies led to rioting and deaths in Venezuela in 2017. - Political unrest has frequently caused inadequate food supplies. - Refugee populations that flee their homes due to war or political unrest typically do not have access to food that they grew and stored but had to leave behind when they became refugees.

High-density animal farming has many environmental and health consequences.

- There is evidence that antibiotics given to confined animals are contributing to an increase in antibiotic-resistant strains of microorganisms that affect humans. - Waste disposal is another serious problem.

Encourage community and stakeholder collaboration in development decisions.

- There is no single "right" way to build a neighborhood; residents and stakeholders—people with an interest in a particular place or issue—need to work together to determine how their neighborhoods will appear and be structured.

effects on biodiversity

- There is some concern that if genetically modified crop plants are able to breed with their wild relatives—as many domesticated crop plants are—the newly added genes will spread to the wild plants. - The spread of such genes might then alter or eliminate natural plant varieties. - The use of genetically modified seeds is contributing to a loss of genetic diversity among food crops. - As with any reduction in biodiversity, we cannot know what beneficial genetic traits might be lost.

Pesticides can cause even wider environmental effects

- They may kill organisms that benefit farmers, such as predatory insects that eat crop pests, pollinator insects that pollinate crop plants, and plants that fix nitrogen and improve soil fertility. - Furthermore, chemical pesticides, like fertilizers, can run off into surrounding surface waters and pollute groundwater

green revolution

- This shift in farming methods, known as the Green Revolution, involved new management techniques and mechanization as well as the triad of fertilization, irrigation, and improved crop varieties. - These changes increased food production dramatically, and farmers were able to feed many more people.

Monocropping has greatly improved agricultural productivity.

- This technique allows large expanses of land to be planted at the same time and later harvested at the same time. - With the use of large machinery, the harvest can be done easily and efficiently. - If fertilizer or pesticide treatments are required, those treatments can also be applied uniformly over large fields, which, because they are planted with the same crop, have the same pesticide or nutritional needs.

Provide a variety of transportation choices

- Transit-oriented development (TOD) attempts to focus dense residential and retail development around public transportation stops, giving people convenient alternatives to driving. - Bicycle racks and safe roads, pleasant sidewalks for walking, frequent bus service, and light rail service can all aid in this goal. - Car-sharing networks such as Zipcar can provide easy access to a fleet of rental automobiles. - This increasingly popular service reduces the need for private car ownership where public transportation is not available. - There is also a trend of developing recreational bicycle and walking trails on abandoned railroad corridors

Create walkable neighborhoods.

- Walkable neighborhoods are created by mixing land uses, reducing the speed of traffic, encouraging businesses to build stores directly up to the sidewalk, and placing parking lots behind buildings. - In neighborhoods that encourage walking, people use their cars less, reducing fossil fuel use and traffic congestion and providing health benefits. - Communities with more pedestrians tend to see more interaction among neighbors because people stop to talk with each other. - This, in turn, creates opportunities for civic engagement. - When people interact, the environment usually benefits.

individual transferable quotas (ITQs)

- a fishery management program in which individual fishers are given a total allowable catch of fish for a season that they can either catch themselves or sell to others. - Before the start of each salmon season, fishery managers establish a total allowable catch and distribute or sell quotas to individual fishers or fishing companies, favoring those with long-term histories in the fishery. - Fishers with ITQs have a secure right to catch their quota so they have no need to spend money on bigger boats and better equipment in order to outcompete others. - If fishers cannot catch enough salmon to remain economically viable, they can sell all or part of their quota to another fisher.

Industrial agriculture, or agribusiness

- applies the techniques of the Industrial Revolution—mechanization and standardization—to the production of food. - Today's modern agribusinesses are quite different from the small family farms that dominated agriculture only a few decades ago.

Habitat or species management areas

- are actively managed for a variety of purposes. - Management may occur in order to maintain biological communities, for example through provision of predator control or fire prevention, or introduction of fire. - Introduction of fire may be beneficial to species that have adapted to reproduce following periodic fires. - For example, certain species of pine trees produce a type of seed cone (called serotinous cones) that has a sticky resin covering the seeds. - The resin prevents the cone from opening and the seeds from being released until a fire of a certain level of intensity occurs. - For the species to propagate, the forest must experience periodic fires.

organic fertilizers

- are composed of organic matter from plants and animals. - They are typically made up of animal manure and crop residues that have been allowed to decompose. - Traditional farmers often spread animal manure and crop wastes onto fields to return some of the nutrients that were removed from those fields when crops were harvested.

forests

- are dominated by trees and other woody vegetation. - Roughly three-quarters of the forests used for commercial timber operations in the United States are privately owned. - Many national forests were originally established to ensure a steady and reliable source of timber, and commercial logging companies are currently allowed to harvest U.S. national forests, usually in exchange for a royalty that is a percentage of their revenues. - The federal government typically spends more money managing the timber program and building and maintaining logging roads than it receives from these royalties, essentially subsidizing the timber program as it does grazing on rangelands.

Strict nature reserves and wilderness areas

- are established to protect species and ecosystems. - There are approximately 6,000 such sites worldwide, covering more than 200 million hectares (490 million acres). - For example, the Chang Tang Reserve on the Tibetan Plateau in China was set aside to protect a number of species—including the declining population of wild yak—from hunting, habitat destruction, and hybridization with domesticated animals.

Managed resource protection areas

- are open for the sustained use of biological, mineral, and recreational resources. - In most countries, these areas are managed for multiple uses. - This means that mining, logging, and other activities are allowed and sometimes encouraged. - In the United States, national forests are one example of this kind of protected area. - Often, in order to remove trees or other resources, roads need to be constructed. - Road construction causes habitat alteration and fragmentation, which can lead to controversies about the use of the area.

Synthetic fertilizers, or inorganic fertilizers

- are produced commercially, normally with the use of fossil fuels. - Nitrogen fertilizers are often produced by combusting natural gas, which allows nitrogen from the atmosphere to be fixed and captured in fertilizer. - Fertilizers produced in this way are highly concentrated, and their widespread use has increased crop yields tremendously since the Green Revolution began. - Synthetic fertilizers have many advantages over organic fertilizers. - They are designed for easy application, their nutrient content can be targeted to the needs of a particular crop or soil, and plants can easily absorb them, even in poor soils.

national wilderness areas

- are set aside with the intent of preserving large tracts of intact ecosystems or landscapes. - Sometimes only a portion of an ecosystem is included. - Wilderness areas are created from other public lands, usually national forests or rangelands, and are managed by the same federal agency that managed them prior to their designation as wilderness areas. - These areas allow only limited human use and are designated as roadless. - Although logging, road building, and mining are banned in national wilderness areas, roads that existed before the designation sometimes remain in use, and activities such as mining that were previously permitted on the land are allowed to continue. More than 43 million hectares (106 million acres) of federal land in 44 states are classified as wilderness.

pesticides

- are substances, either natural or synthetic, that kill or control organisms that people consider pests. - The use of pesticides has become routine and widespread in modern industrial agriculture

national wildlife refuge

- are the only federal public lands managed for the primary purpose of protecting wildlife. - The Fish and Wildlife Service manages more than 560 national wildlife refuges and 38 wetland management areas on 61 million hectares (150 million acres) of publicly owned land.

the tragedy of the commons

- at least some land was viewed as a common resource: Anyone could use certain spaces for foraging, growing crops, felling trees, hunting, or mining. - But as populations increased, common lands tended to become degraded—overgrazed, overharvested, and deforested. - In 1968, ecologist Garrett Hardin brought the issue of overuse of common resources to the attention of the broader scientific community. - Because people often act from self-interest for short-term gain, Hardin observed that when many individuals share a common resource without agreement on or regulation of its use, it is likely to become overused and depleted very quickly. - The tendency for a shared, limited resource to become depleted if it is not regulated in some way is known as the tragedy of the commons. - Regulation might be managed by the users or by a governmental agency.

highway trust fund

- begun by the Highway Revenue Act of 1956 and funded by a federal gasoline tax, pays for the construction and maintenance of roads and highways. - We have already seen that highways allow people to live farther from where they work. - More highways mean more driving and more gasoline purchases, which lead to more gasoline tax receipts that pay for more roads, and so on. - As people move farther away from their jobs, traffic congestion increases, and roads are expanded. - But the new, larger roads encourage even more people to live farther away from work. - This cycle exemplifies a phenomenon known as induced demand, in which an increase in the supply of a good causes demand to grow.

Protected landscapes and seascapes

- combine the nondestructive use of natural resources with opportunities for tourism and recreation. - Orchards, villages, beaches, and other such areas make up the 6,500 such sites worldwide, which cover more than 100 million hectares (250 million acres). Among these protected areas is the Batanes Protected Landscape and Seascape in the northernmost islands of the Philippines, home to several endemic plant and animal species as well as important marine habitats.

clear cutting

- involves removing all, or almost all, the trees within an area; it is the easiest harvesting method and, in most cases, the most economical. - When a stand, or cluster, of trees has been clear-cut, foresters sometimes replant or reseed the area. - Often the entire area will be replanted at the same time, so all the resulting trees will be the same age. - Because they are exposed to full sunlight, clear-cut tracts of land are ideal for fast-growing tree species that achieve their maximum growth rates with large amounts of direct sunlight. - Because other species may not be so successful in these conditions, there can be an overall reduction in biodiversity. - If a commercially valuable tree species constitutes only a small fraction of a stand of trees, it may not be economically efficient to clear-cut the entire stand. - This is particularly true in many tropical forests, where economically valuable species constitute only a small percentage of the trees and are mixed in with many other less valuable species.

externality

- is a cost or benefit of a good or service that is not included in the purchase price of that good or service, or otherwise not accounted for. - For example, if a bakery moves into the building next to you and you wake up every morning to the delicious smell of freshly baked bread, you are benefiting from a positive externality. - On the other hand, if the bakers arrive at three in the morning and make so much noise that they interrupt your sleep, making you less productive at your job later that day, you are suffering from a negative externality.

zoning

- is a planning tool developed in the 1920s and used to separate industry and business from residential neighborhoods, thereby creating quieter, safer communities. - Governments that use zoning can classify land areas into "zones" in which certain land uses are restricted. - For instance, zoning ordinances might prohibit developers from building a factory or a strip mall in a residential area or a multi-dwelling apartment building in a single-home neighborhood. - Nearly all metropolitan governments across the United States have adopted zoning.

no-till agriculture

- is an agricultural method in which farmers do not turn the soil between seasons and is used as a means of reducing topsoil erosion. - No-till agriculture is designed to avoid the soil degradation that comes with conventional agricultural techniques. - Farmers using this method leave crop residues in the field between seasons - The intact roots hold the soil in place, reducing both wind and water erosion, and the undisturbed soil is able to regenerate natural soil horizons. - No-till agriculture also reduces emissions of CO2 because the intact soil undergoes less oxidation and carbon stored in the soil is more likely to remain there. - In many cases, however, in order for no-till agriculture to be successful, farmers must apply herbicides to the fields before, and sometimes after, planting so that weeds do not compete with the crops. - Therefore, the downside of no-till methods is an increase in the use of herbicides.

Organic agriculture

- is the production of crops in a way that sustains or improves the soil, without the use of synthetic pesticides or fertilizers. - Organic agriculture follows several basic principles: --Use ecological principles and work with natural systems rather than dominating those systems. --Maintain the soil by increasing soil mass, biological activity, and beneficial chemical properties. --Keep as much organic matter and as many nutrients in the soil and on the farm as possible. --Avoid the use of synthetic fertilizers and synthetic pesticides. --Reduce the adverse environmental effects of agriculture.

While irrigation has many benefits, including more efficient use of water, it can also have a number of negative consequences over time.

- it can deplete groundwater, draw down aquifers, and cause saltwater intrusion into freshwater wells. - It can also contribute to soil degradation through waterlogging and salinization - Waterlogging, a form of soil degradation that occurs when soil remains under water for prolonged periods, impairs root growth because roots cannot get oxygen. - Salinization occurs when the small amounts of salts in irrigation water become highly concentrated on the soil surface through evaporation. - These salts can eventually reach toxic concentrations and impede plant growth.

nonpersistent pesticides

- meaning that they break down relatively rapidly, usually in weeks to months. - Nonpersistent pesticides have fewer long-term effects, but because they must be applied more often, their overall environmental impact is not always lower than that of persistent pesticides.

maximum sustainable yield

- of a renewable resource is the maximum amount that can be harvested without compromising the future availability of that resource. - In other words, it is the maximum harvest that will be adequately replaced by population growth. - A reasonable starting point is to assume that population growth is the fastest at about one-half the carrying capacity of the environment, as shown on the S-shaped curve - Looking at the graph, we can see that at a small population size, the growth curve is shallow and growth is relatively slow. - As the population increases in size, the slope of the curve is steeper, indicating a faster growth rate. - As the population size approaches the carrying capacity, the growth rate slows. - The MSY is the amount of harvest that allows the resource population to be maintained at roughly one-half the carrying capacity of the environment.

malnourished

- regardless of the number of calories they consume, their diets lack the correct balance of proteins, carbohydrates, vitamins, and minerals. - These people experience malnutrition

overnutrition

- the ingestion of too many calories combined with a lack of proper balance in foods and nutrients, causes a person to become both overweight and malnourished. - The WHO estimates that there are almost 2 billion adults in the world who are overweight, and that roughly 600 million of these people are obese, meaning they are more than 20 percent above their ideal weight. - Overnutrition is a type of malnutrition that puts people at risk for a variety of diseases, including type 2 diabetes, hypertension, heart disease, and stroke. - While overnutrition is common in developed countries such as the United States, it can also coexist with malnutrition in developing countries. - Childhood obesity is a related condition that now occurs in greater numbers as well. - Overnutrition is often a function of the availability and affordability of certain kinds of foods. - For example, overnutrition in the United States has been attributed in part to the easy availability and low cost of processed foods containing ingredients such as high-fructose corn syrup, which are often high in calories but lack other nutritional content.

The primary reason for undernutrition and malnutrition is poverty

- the lack of resources that allows a person to have access to food. - According to many food experts, starvation on a global scale is the result of unequal distribution of food rather than absolute scarcity of food. - In other words, the food exists but not everyone has access to it. - This may mean that people cannot afford to buy the food they need, which is a problem that cannot be solved just by producing more grain.

meat

- the second largest component of the human diet, is usually defined as livestock (beef, veal, pork, and lamb) and poultry (chicken, turkey, and duck) consumed as food. - As income increases with economic growth, people tend to add more meat to their diet. - However, in relatively affluent countries, concerns about health consequences of eating "too much" meat or perhaps concerns about the environmental consequences of eating meat sometimes results in a reduction in per capita meat consumption

integrated pest management (IPM)

- uses a variety of techniques designed to minimize pesticide inputs. - These techniques include crop rotation and intercropping, the use of pest-resistant crop varieties, the creation of habitats for predators of pests, and limited use of pesticides.

tree plantations

- which are large areas typically planted with a single rapidly growing tree species. - These same-aged stands can be easily clear-cut for commercial purposes, such as pulp and wood, and then replanted. - Because of this cycle of planting and harvesting, tree plantations never develop into mature, ecologically diverse forests. - If too many planting and harvesting cycles occur, the soil may become depleted of important nutrients such as calcium.

concentrated animal feeding operations (CAFOs)

- which are large indoor or outdoor structures designed for maximum output - is used for beef cattle, dairy cows, hogs, and poultry, all of which are confined or allowed very little room for movement during all or part of their life cycle. - By keeping animals confined, farmers minimize land costs, improve feeding efficiency, and increase the fraction of food energy that goes into the production of animal body mass. - Keeping animals confined to a small space, which is criticized by some on ethical grounds, ensures that less energy is expended by the animal in activities such as moving around and the increased respiration that will result. - The animals are given antibiotics and nutrient supplements to reduce the risk of adverse health effects and diseases, which would normally be high in such highly concentrated animal populations.

resource conservation ethic

- which states that people should maximize resource use based on the greatest good for everyone. - The resource conservation ethic calls for policy makers to consider the resource or monetary value of nature. - In conservation and land use terms, it has meant that areas are preserved and managed for economic, scientific, recreational, and aesthetic purposes.

crop rotation

achieves the same effect by rotating the crop species in a field from season to season.

agroforestry

allows vegetation of different heights, including trees, to act as windbreaks and to catch soil that might otherwise be blown away, greatly reducing erosion