Exam 1 Flashcards
(76 cards)
1
Q
ecosystem
A
An ecosystem is a biological community of organisms within a defined area of land or volume of water that interact with one another and with their environment of nonliving matter and energy. For example, a forest ecosystem consists of trees and other plants, animals, and organisms that decom- pose organic materials.
2
Q
ecosystem services
A
the natural services provided by healthy ecosystems that support life and human econo- mies at no monetary cost to us (Figure 1.3). Key ecosystem services include purification of air and water, renewal of topsoil, pollination, and pest control. For example, forests help purify air and water, reduce soil erosion, regulate cli- mate, and recycle nutrients. Thus, our lives and econo- mies are sustained by energy from the sun and by natural resources and ecosystem services (natural capital) provided by the earth
3
Q
biodiversity
A
The variety of genes, species, ecosystems, and ecosystem processes are referred
to as biodiversity (short for biological diversity). Interactions among species provide vital ecosystem services and keep any population from growing too large. Biodiversity also provides ways for species to adapt to changing environmental conditions and for new species to arise and replace those wiped out by catastrophic environmental changes.
4
Q
ecology
A
the branch of biology that focuses on how living organ- isms interact with the living and nonliving parts of their environment
5
Q
ecological footprint
A
The effects of environmental degradation by human activities can be described as an ecological footprint—a rough measure of the total environmental impacts of individu- als, cities, and countries on the earth’s natural resources, natural capital, and life-support system.
6
Q
native species
A
those that normally live and thrive in a particular ecosystem.
7
Q
invasive species
A
Other species that migrate into or that are deliberately or accidentally introduced into an eco- system
8
Q
extinction
A
when an entire species ceases to exist- when environment changes dramatically
9
Q
rate of extinction
A
Species are becoming extinct at least 100 times faster than in prehuman times and extinction rates are projected to increase sharply during this century.
10
Q
age structure
A
in a pop, its distribution of individuals among various age groups—can have a strong effect on how rapidly its numbers grow or decline.
11
Q
crude birth rate
A
the number of live births per 1,000 people in a population in a given year
12
Q
crude death rate
A
the number of deaths per 1,000 people in a population in a given year
13
Q
cultural carrying capacity
A
the maximum number of people who could live in reasonable freedom and comfort indefinitely, without decreasing the ability of the earth to sustain future generations
14
Q
demographic transition
A
Demographers have examined the birth and death rates of western European countries that became industrialized during the 19th century. Using such data, they developed a hypothesis on population change known as the demographic transition. It states that as countries become industrialized and economically developed, their per capita incomes rise, poverty declines, and their populations tend to grow more slowly. According to the hypothesis, this transition takes place in four stages, as shown in Figure 6.14.
15
Q
family planning
A
programs that provide education and clinical services that can help couples to choose how many children to have and when to have them. Such programs vary from culture to culture, but most of them provide information on birth spacing, birth control, and health care for pregnant women and infants.
16
Q
infant mortality rate
A
the number of babies out of every 1,000 born who die before their first birthday. It is viewed as one of the best measures of a soci- ety’s quality of life because it indicates the general level of nutrition and health care.
17
Q
life expectancy
A
the average number of years a person born in a particular year can be expected to live. Between 1955 and 2018, average global life expectancy increased from 48 years to 72 years. Between 1900 and 2018, the average U.S. life expectancy rose from 47 years to 79 years. Research indicates that poverty, which reduces the average life span by 7 to 10 years, is the single most important factor affecting life expectancy. For example, the average life expectancy in the world’s 10 poorest nations is 55 years compared to 80 years in the 10 wealthiest nations.
18
Q
migration
A
the movement of people into (immigration) and out of (emigra- tion) specific geographic areas. Most people who migrate to another area within their country or to another country are seeking jobs and economic improvement. Others are driven by religious persecution, ethnic conflicts, political oppression, or war. There are also environmental refugees— people who have to leave their homes and sometimes their countries because of water or food shortages, soil erosion, or some other form of environmental degradation.
19
Q
population change
A
The human population in a particular area grows or declines through the interplay of three factors: births (fertility), deaths (mortality), and migration. We can calcu- late the population change of an area by subtracting the number of people leaving a population (through death and emigration) from the number entering it (through birth and immigration) during a year:
Population change =(Births+Immigration)-(Deaths+Emigration)
20
Q
total fertility rate
A
It is the average number of children born to the women of childbearing age in a population. It is a key factor affecting human population growth and size.
Between 1955 and 2018, the global TFR dropped from 5.0 to 2.4.
21
Q
replacement level fertility
A
the average number of children that couples in a population must bear to replace themselves. It is slightly higher than two children per couple (typically 2.1) because some chil- dren die before reaching their reproductive years, especially in the world’s poorest countries.
22
Q
exponential growth
A
occurs when a quantity increases at a fixed percentage per unit of time, such as 0.5% or 2% per year. Exponential growth starts slowly, but after a few doublings it grows to enormous numbers because each doubling is twice the total of all earlier growth.
23
Q
J and S shape growth curves
A
As a population approaches the carrying capacity of its habitat, the J-shaped curve of its exponential growth (Figure 5.16, left) is converted to an S-shaped curve of logistic growth, or growth that often fluctuates around the carrying capacity of its habitat
24
Q
cultural eutrophication
A
Human inputs of nutrients through the atmosphere and from urban and agricultural areas within a lake’s water- shed can accelerate the eutrophication of the lake.
Over time, sediments, organic material, and inorganic nutrients wash into most oligotrophic lakes, and plants grow and decompose to form bottom sediments.Over time, sediments, organic material, and inorganic nutrients wash into most oligotrophic lakes, and plants grow and decompose to form bottom sediments.
25
nonpoint sources
broad and diffuse areas where rainfall or snowmelt washes pollutants off the land into bodies of surface water. Examples include runoff of eroded soil and chemicals such as fertilizers and pesticides from cropland, animal feedlots, logged forests
26
point sources
discharge pollutants into bodies of surface water at specific locations often through drain pipes, ditches, or sewer lines. Examples include factories (Figure 20.2), sewage treatment plants (which remove some, but not all, pollutants), open-pit mines (Figure 20.3), oil wells, and oil tankers.
27
biodegradable vs non-biodegradable pollutant
Material that can be broken down into simpler sub- stances (elements and compounds) by bacteria or other decomposers. Paper and most organic wastes such as animal manure are biodegradable but can take decades to biodegrade in modern landfills. Compare nondegradable pollutant.
28
biological magnification
as the chemical moved up through food chains and webs, it became successively more con- centrated in the fatty tissues of higher-level organisms—a process called biomagnification
29
oxygen depleted zones/dead zones
Today, more than 400 oxygen-depleted zones (“dead zones”) have formed in coastal areas around the world, and the number is increasing. They form when high levels of plant nutrients from fertilizers and soil erosion flow from the land into rivers that empty into coastal waters. These inputs support large algal blooms
30
ocean pollution
Coastal areas such as wetlands, estuaries, coral reefs, and mangrove swamps receive the largest inputs of pollutants and wastes (Figure 20.15). About 37% of the world’s people (40% in the United States) live on or near coastlines, and coastal populations are projected to double by 2050. This explains why 80% of marine pollution originates on land.
Oceans help recycle the planet’s freshwater through the water cycle (Figure 3.19). They also affect weather and climate, help regulate the earth’s temperature, and absorb some of the massive amounts of carbon dioxide and heat that human activities emit into the atmosphere
31
groundwater pollution
Water that seeps deeper into the soil is known as groundwater. Groundwater collects in aquifers, which are underground layers of water-bearing rock. Some pre- cipitation is converted to ice that is stored in glaciers.
Hurricanes can also lead to water pollution. North Carolina is the third largest producer of hogs in the United States. Most of the hogs are raised for slaughter in large factory farms and their untreated wastes are stored in more than 3,000 open-air lagoons. In 2018, rain from Hurricane Florence caused many of these lagoons to overflow or lose their protective walls. This released huge amounts of hog waste, which contaminated waterways and groundwater in much of the state.
A serious but hidden threat to human health. Common pol- lutants such as fertilizers, pesticides, gasoline, and organic solvents can seep into groundwater from numerous sources (Figure 20.11). People who dump or spill gasoline, oil, and paint thinners and organic solvents onto the ground can also contaminate groundwater.
The drilling of thousands of new oil and natural gas wells in parts of the United States involving a process called hydrau- lic fracturing, or fracking is a new and growing potential threat to groundwater in the United States.
32
primary sewage treatment
a physical process that uses screens and a grit tank to remove large float- ing objects and to allow solids such as sand and rock to settle out. Then the waste stream flows into a primary settling tank where suspended solids settle out as sludge (Figure 20.22, left).
33
secondary sewage treatment
a biological process in which oxygen is added to the sew- age in an aeration tank to encourage aerobic bacteria to decompose as much as 90% of dissolved and biodegradable, oxygen-demanding organic wastes (Figure 20.22, right). A combination of primary and secondary treatment removes 95–97% of the suspended solids and oxygen- demanding organic wastes, 70% of most toxic metal compounds and degradable synthetic organic chemicals, 70% of the phosphorus, and 50% of the nitrogen. However, this process removes only a tiny fraction of persistent and potentially toxic organic substances found in some pesticides and in discarded medicines that people put into sewage systems, and it does not kill disease-causing bacteria and viruses. It also does not remove many of the toxic chemicals in wastewater that industries and fracking operations send to sewage treatment plants.
34
tertiary sewage treatment
A third level of cleanup, advanced or tertiary sewage treatment, uses a series of specialized chemical and physi- cal processes to remove specific pollutants left in the water after primary and secondary treatment. In its most com- mon form, advanced sewage treatment uses special fil- ters to remove phosphates and nitrates from wastewater before it is discharged into surface waters. This third stage would significantly reduce nutrient overload from nitrates and phosphates, but is not widely used because of its high cost.
35
water pollution
any change in water quality that can harm living organisms or make the water unfit for human uses such as drinking, irrigation, and recreation. Water pol- lution can come from single (point) sources or from larger and dispersed (nonpoint) sources
36
acid deposition and its harmful effects
Humans intervene in the nitrogen cycle in several ways (see red arrows in Figure 3.21). When we burn gasoline and other fuels, the resulting high temperatures convert some of the N2 and O2 in air to nitric oxide (NO). In the atmosphere, NO can be converted to nitrogen dioxide gas (NO ) and nitric acid vapor (HNO ), which can return to the earth’s surface as damaging acid deposition, commonly called acid rain. Acid rain damages stone buildings and statues.
Acid deposition damages stone and metals in buildings and stat- ues (Figure 18.4), contributes to human respiratory diseases, and can leach toxic metals such as lead and mercury from soils and rocks into lakes used as sources of drinking water. These toxic metals can accumulate in the tissues of fish eaten by people (especially pregnant women) and other animals. Currently, 45 U.S. states have issued warnings telling people to avoid eating fish caught from waters that are contaminated with toxic mercury
37
air pollution
is the presence of chemicals in the atmo- sphere in concentrations high enough to harm organisms, ecosystems, or human-made materials, or to alter climate. Almost any chemical in the atmosphere can become a pollutant if it occurs in a high enough concentration. The effects of air pollution range from annoying to lethal.
38
greenhouse gases
Gases in the lower atmosphere affect its temperature and thus the earth’s climates. As energy flows from the sun to the earth, some of it is reflected by the earth’s surface back into the atmosphere. Molecules of certain gases in the atmosphere, including water vapor (H2O), carbon dioxide (CO2 ), methane (CH4 ), and nitrous oxide (N2O), absorb some of this solar energy and release a portion of it as infrared radiation (heat) that warms the lower atmosphere and the earth’s surface. These gases, called greenhouse gases, play a role in determining the lower atmosphere’s average tem- peratures and thus the earth’s climates.
39
greenhouse effect
the earth’s surface also absorbs much of the solar energy that strikes it and transforms it into longer-wavelength infrared radiation, which then rises into the lower atmo- sphere. Some of this heat escapes into space, but some is absorbed by molecules of greenhouse gases and emitted into the lower atmosphere as even longer-wavelength infrared radiation (see Figure 2.12). Some of this released energy radiates into space, and some adds to the warming of the lower atmosphere and the earth’s surface. This natural warming of the troposphere, called the greenhouse effect
40
industrial smog
People in such cities also burned coal to heat their homes and to cook food. Often, especially during winter, they were exposed to industrial smog, consisting mostly of an unhealthy mix of sulfur dioxide (SO2 ), sus- pended droplets of sulfuric acid, and a variety of suspended solid particles in outside air. People who burned coal inside their homes were often exposed to dangerous levels of par- ticulates and other indoor air pollutants.
41
ozone layer & depletion
Most of the atmosphere’s ozone is concentrated in a portion of the stratosphere called the ozone layer, found roughly 17–26 kilometers (11–16 miles) above sea level (Figure 18.2). Most of the ozone in this layer is produced when oxygen molecules interact with ultraviolet (UV) radi- ation emitted by the sun.
However, measurements taken by researchers revealed a considerable seasonal depletion, or thinning, of ozone concentrations in the stratosphere above Antarctica (Figure 18.29) and above the Arctic since the 1970s. Similar Low measurements reveal slight overall ozone thinning everywhere except over the tropics. The loss of ozone over Antarctica has been called an ozone hole. A more accurate term is ozone thinning because the ozone depletion varies with altitude and location.
42
photochemical smog
an unhealthy mix of ozone and other chemicals that threatened human health
a mixture of chemicals formed under the influence of sunlight in cities with heavy traffic (Core Case study). Nitrous oxide (N2O), a greenhouse gas, is emitted from fertilizers and animal wastes and is produced by the burning of fossil fuels.
It is a brownish mixture of primary and secondary pollutants formed when certain gases in the atmosphere mostly those emitted by automobiles and trucks react with UV radia- tion from the sun. The formation of photochemical smog (Figure 18.8) begins when exhaust from morning com- muter traffic releases large amounts of NO and VOCs into the air over a city. The NO is converted to reddish-brown NO2, which is why photochemical smog is sometimes called brown-air smog
43
primary pollutants
chemi- cals emitted directly into the air from natural processes and human activities at concentrations high enough to cause harm.
44
secondary air pollutants
while in the atmosphere, some primary pol- lutants react with one another and with other natural components of air to form new harmful chemicals, called secondary pollutants.
45
indoor air pollutants
Indoor air pollution has become a major health concern all over the world. In less-developed countries, the indoor burning of wood, charcoal, dung, crop residues, coal, and other fuels in open fires (Figure 18.15) and in unvented or poorly vented stoves exposes people to dangerous lev- els of particulate air pollution. The WHO has estimated that indoor air pollution kills about 3.8 million people per year—an average of 10,410 deaths per day—mostly in less- developed countries. Indoor air pollution is also a serious problem in the United States and in more-developed areas of all countries. According to the EPA and public health officials, the three most dangerous indoor air pollutants in such areas are tobacco smoke (see Chapter 17, Case Study); formaldehyde emitted from many building materials and various house- hold products; and radioactive radon-222 gas, which can seep into houses from underground rock deposits (see the Case Study that follows).
46
stratosphere
the atmospheric layer above the troposphere. It reaches 17 to 50 kilometers (12–31 miles) above the earth’s surface. The lower stratosphere, called the ozone layer, contains enough ozone (O3 ) gas to filter out about 95% of the sun’s harmful ultraviolet (UV) radiation. It acts as a global sunscreen that allows life to exist on the earth’s surface.
47
air pollution reducing technologies
One commonly used technological solution is the electrostatic precipitator (Figure 18.24, left). It is simple to maintain and can remove up to 99% of the particulate mat- ter it processes. However, it uses a lot of electricity and pro- duces a toxic dust that must be disposed of safely. Another is the wet scrubber (Figure 18.24, right), which uses a stream of water droplets to dissolve and remove up to 98% of SO2 and 98% of the particulate matter in smokestack emissions. However, it produces waste in the form of sludge that must be disposed of in a landfill.
48
cap and trade
49
chlorofluorocarbons
Organic compounds, made up of atoms of carbon, chlorine, and fluorine, which can deplete the ozone layer when they slowly rise into the stratosphere and react with ozone molecules.
a compound that contains car- bon, chlorine, and fluorine. Chemists soon developed simi- lar compounds to create a family of highly useful CFCs, known by their trade name FreonsTM.
These chemically unreactive, odorless, nonflammable, nontoxic, and noncorrosive compounds were thought to be dream chemicals. Inexpensive to manufacture, they became popular as coolants in air conditioners and refrig- erators, propellants in aerosol spray cans, cleansers for elec- tronic parts such as computer chips, fumigants for granaries and ships’ cargo holds, and gases used to make insulation and packaging.
It turned out that CFCs were too good to be true. Starting in 1974 with the work of chemists Sherwood Rowland and Mario Molina (Individuals Matter 18.1), scientists showed that CFCs are persistent chemicals that reach the stratosphere and destroy some of its pro- tective ozone.
50
Montreal protocol
In 1987, representatives of 36 nations met in Montreal, Canada, and developed the Montreal Protocol. This treaty’s goal was to cut emissions of CFCs (but no other ozone- depleting chemicals) by about 35% between 1989 and 2000.
The Montreal Protocol is viewed as the world’s most successful global environmental agreement. It set an impor- tant precedent because nations and companies worked together and used a prevention approach to solve a serious environmental problem.
51
biomimicry
the rapidly growing scientific effort to understand, mimic, and catalog the ingenious ways in which nature has sustained life on the earth for 3.8 billion years. she views the earth’s life-support system as the world’s longest and most successful research and development laboratory.
52
chemical cycling
The circulation of chemicals or nutrients needed to sustain life from the environment (mostly from soil and water) through various organisms and back to the environment is called chemical cycling, or nutrient cycling. The earth receives a continuous supply of energy from the sun, but it receives no new supplies of life-supporting chemicals. Through billions of years of interactions with their living and nonliving environment, organisms have developed ways to recycle the chemicals they need to survive. This means that the wastes and decayed bodies of organisms become nutrients or raw materials for other organisms. In nature, waste 5 useful resources.
53
environmentally sustainable
protects natural capital and lives on its income. Such a society would meet the current and future basic resource needs of its people in a just and equitable manner without compromising the ability of future generations to meet their basic resource needs.
This is in keeping with the ethical principle of sustainability.
54
full-cost pricing
Some economists urge us to find ways to include the harmful environmental and health costs of producing and using goods and services in their market prices. This practice, called full-cost pricing,
would give consumers information about the harmful environmental impacts of the goods and services they use.
55
inexhaustible resource
Solar energy is an inexhaustible resource because it is expected to last for at least 5 billion years until the death of the star we call the sun.
56
natural capital
natural resources and ecosystem services that keep humans and other species alive and that support human economies
57
natural capital degradation
According to a large body of scientific evidence, we are living unsustainably. People waste, deplete, and degrade much of the earth’s life-sustaining natural capital—a pro- cess known as environmental degradation, or natural capital degradation
58
additional scientific principles of sustainability
Economics, politics, and ethics can provide us with three additional principles of sustainability (Figure 1.7):
* Full-cost pricing (from economics): Some economists urge us to find ways to include the harmful environmental and health costs of producing and using goods and services in their market prices. This practice, called full-cost pricing,
would give consumers information about the harmful environmental impacts of the goods and services they use.
* Win-win solutions (from political science): Political scientists urge us to look for win-win solutions to environmental problems. This involves cooperation and compromise that will benefit the largest number of people as well as the environment.
* Responsibility to future generations (from ethics): According to environmental ethicists, we have a responsibility to leave the planet’s life-support systems in a condition as good as or better than what we inherited for future generations and for other species.
59
scientific principles of sustainability
Scientific studies of how the earth works reveal that three science-based natural factors play key roles in the long-term sustainability of the planet’s life, as summarized below and in Figure 1.2. Understanding these three scientific principles of sustainability, or major lessons
from nature, can help us move toward a more sustain-
able future.
* Solar energy: The sun’s energy warms the planet and provides energy that plants use to produce nutrients, the chemicals that plants and animals need to survive.
* Biodiversity: The variety of genes, species, ecosystems, and ecosystem processes are referred
to as biodiversity (short for biological diversity). Interactions among species provide vital ecosystem services and keep any population from growing too large. Biodiversity also provides ways for species to adapt to changing environmental conditions and for new species to arise and replace those wiped out by catastrophic environmental changes.
* Chemical cycling: The circulation of chemicals or nutrients needed to sustain life from the environment (mostly from soil and water) through various organisms and back to the environment is called chemical cycling, or nutrient cycling. The earth receives a continuous supply of energy from the sun, but it receives no new supplies of life-supporting chemicals. Through billions of years of interactions with their living and nonliving environment, organisms have developed ways to recycle the chemicals they need to survive. This means that the wastes and decayed bodies of organisms become nutrients or raw materials for other organisms. In nature, waste 5 useful resources.
60
sustainable yield
The highest rate at which people can use a renewable resource indefi- nitely without reducing its available supply is called its maximum sustainable yield
61
feedback loop
A system is any set of components that function and interact in some regular way. Examples are a cell, the human body, a forest, an economy, a car, a TV set, and the earth.
Most systems have three key components: inputs of matter, energy, and information from the environment; flows or throughputs of matter, energy, and informa- tion within the system; and outputs of matter, energy, and information to the environment (Figure 2.14). A system can become unsustainable if the throughputs of matter andMost systems are affected by feedback, any process that increases (positive feedback) or decreases (negative feedback) a change to a system. Such a process, called a feedback loop, occurs when an output of matter, energy, or information is fed back into the system as an input and changes the system. A positive feedback loop causes a system to change further in the same direction. For example, when resear- chers removed the vegetation from a stream valley in the Hubbard Brook Experimental Forest (Core Case study), they found that flowing water from precipitation caused erosion and losses of nutrients, which caused more vegetation to die (Figure 2.15). With even less vegetation to hold soil in place, flowing water caused even more erosion and nutrient loss, which caused even more plants to die.
When a natural system becomes locked into a positive feedback loop, it can reach a tipping point. Beyond this point, the system can change so drastically that it suffers from severe degradation or collapse. Reaching and exceed- ing a tipping point is somewhat like stretching a rubber band. We can get away with stretching it to several times its original length. At some point, however, we reach an irreversible tipping point where the rubber band breaks. Similarly, if you lean back on the two rear legs of a chair, at some point the chair will tip back and you will land on
A negative, or corrective, feedback loop causes a system to change in the opposite direction. A simple exam- ple is a thermostat, a device that measures the temperature in a house and uses this information to turn its heating or cooling system on or off to achieve a desired temperature (Figure 2.16).
Another example of a negative feedback loop is the recy- cling of aluminum. An aluminum can is an output of mining and manufacturing systems that requires large inputs of energy and matter and that produces pollution and solid waste. When we recycle, the output (the used can) it becomes an input that reduces the need for mining aluminum and manufacturing the can. This reduces the energy and matter inputs and the harmful environmental effects.
This is an application of the chemical cycling principle
of sustainability.
Occurs when an output of matter, energy, or information is fed back into the system as an input and leads to changes in that system. See positive feedback loop and negative feedback loop.
62
photosynthesis
Producers are organisms, such as green plants, that make the nutrients they need from compounds and energy obtained from their environment. In the process known as photosynthesis, green plants capture solar energy that falls on their leaves. They use it to combine carbon dioxide and water to form carbohydrates such as glucose (C6 H12O6 ), which they store as a source of chemical energy. In the pro- cess, they emit oxygen (O2 ) gas into the atmosphere. This oxygen keeps us and most other animal species alive. The following chemical reaction summarizes the overall process of photosynthesis.
63
habitat
Large areas of forest and other biomes tend to have a
core habitat and edge habitats with different environmental conditions and species, called edge effects. For example, a forest edge is usually more open, bright, and windy and has greater variations in temperature and humidity than a for- est interior. Humans have fragmented many forests, grass- lands, and other biomes into isolated patches with less core habitat and more edge habitat that supports fewer species.
A species’ niche differs from its habitat, which is the place, or type of ecosystem, in which a species lives and obtains what it needs to survive.
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population
One strategy, known as carbon capture and storage (CCS), would remove some of the CO2 from smokestack emissions of coal-burning power and industrial plants and convert it to a liquid to be pumped under pressure into underground storage sites (Figure 19.21).
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carbon footprint
In comparing sources of CO2 emissions, scientists use the concept of a carbon footprint. It refers to the amount of CO2 generated by an individual, an organization, a coun- try, or any other entity over a given period. A per capita carbon footprint is the average footprint per person in a population.
66
climate change
Climate change also threatens aquatic biodiversity and eco-system services. Greenhouse gas emissions and heat, mostly from the burning of fossil fuels, have played an important role in warming the atmosphere and changing the earth’s climate. For decades, the earth’s oceans have absorbed about 90% of this excess heat. If they had not, the earth’s atmosphere would be much warmer and the climate would be changing much more rapidly. As energy expert John Abraham puts it: “The ocean is doing us a favor by grab- bing about 90% of our heat output. But it is not going to do it forever.”
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ocean acidification
As a result, levels of CO2 in the atmosphere have been rising sharply since about 1960. There is consid- erable scientific evidence that this disruption of the carbon cycle is helping to warm the atmosphere and change the earth’s climate. The oceans remove some of this CO2 from the atmosphere but as a result, the acid- ity of ocean waters is rising.
The newest growing threat is ocean acidification—the rising levels of acidity in ocean waters. This is occurring because the oceans absorb about 25% of the CO2 emitted into the atmosphere by human activities, primarily from the burning of fossil fuels. The CO2 reacts with ocean water to form a weak acid (carbonic acid, H2CO3). This reaction decreases
the levels of carbonate ions (CO 22) necessary for the formation of coral reefs and the shells and skeletons of many marine organisms. This makes it harder for these species to thrive and reproduce. At some point, this rising acidity could slowly dissolve corals and the shells and skeletons of some marine species.
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carbon tax/credit
For over 40 years, U.S. coal and electric utility industries have successfully fought to keep government subsidies and tax breaks and prevent coal regulations and taxes on carbon emissions because it would increase the cost of using coal and sharply reduce their profits. This would make it less com- petitive with other, cleaner and increasingly cheaper ways to produce electricity from natural gas, wind, and the sun.
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Kyoto protocol
Governments have entered into international climate nego- tiations. In December 1997, delegates from 161 nations met in Kyoto, Japan, to negotiate a treaty to slow atmospheric warming and projected climate change. The first phase of the resulting Kyoto Protocol went into effect in February 2005 with 187 of the world’s 194 countries (not including the United States) ratifying the agreement by late 2009.
The 37 participating more-developed countries agreed to cut their emissions of CO2, CH4, and N2O to certain levels by 2012. However, 16 of the nations failed to do so. Less- developed countries, including China, were excused from this requirement, because such reductions would curb their economic growth.
In 2015, delegates from 195 countries met in Paris, France, in another attempt to achieve a global climate change agreement. In a historic agreement, the govern- ments agreed to the following:
* Accepting a goal to keep the increase in global average temperatures below 28C (3.68F).
* Pledging to reduce their greenhouse gas emissions by a set amount.
* Meeting every 5 years to evaluate progress and raise their goals.
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IPCC
According to the Intergovernmental Panel on Climate Change (IPCC), each 18C (1.88F) increase in the global average temperature is likely to increase the area of forest that burn in the west- ern United States by a factor of 2 to 5.
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natural factors leading to climate change
Climate change is neither new nor unusual. Over the past 3.5 billion years, many factors have altered the planet’s cli- mate. These natural factors include:
(1) massive volcanic eruptions and impacts by meteors and asteroids that cool the earth by injecting large amounts of debris into atmosphere;
(2) changes in solar input that can warm or cool the earth;
(3) slight changes in the shape of the earth’s orbit around the sun from mostly circular to more elliptical over a 100,000-year cycle;
(4) slight changes in the tilt of the earth’s axis over a 41,000-year cycle;
(5) slight changes in the earth’s wobbly orbit around the sun over a 20,000-year cycle. Factors 3, 4, and
5 together are known as the Milankovitch cycles;
(6) global air circulation patterns (see Figure 7.9); (7) changes in sizes of areas of ice (see Figure 19.1)
that reflect incoming solar energy and cool the
atmosphere,
(8) changes in atmospheric concentrations of the
greenhouse gases—those gases in the atmosphere that trap heat near the earth’s surface that otherwise would escape into space; and
(9) occasional changes in ocean currents.
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geoengineering
Other proposed strategies for slowing atmosphere warm- ing and the resulting climate change fall under the umbrella of geoengineering. They involve trying to manipulate certain natural conditions to help coun- ter the human-enhancement of the earth’s natural greenhouse effect. Some of these proposals are shown (Figure 19.22).
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climate change tipping point
thresholds beyond which change to natural processes could last for hundreds to thousands of years. Figure 19.9 list several possible climate change tipping points.
Most of these tipping points are related to how much the world’s average atmospheric temperature increases. The world’s current average atmospheric temperature is 1C (1.8F) above preindustrial temperatures. According to the 2018 IPCC report, it is likely that the planet will warm 1.5 C (2.7F) between 2032 and 2050, and some cli- mate scientists view IPCC projections as too conservative. Because we have delayed dealing with the serious threat of climate change for over 40 years, some scientists suggest that we can no longer avoid a global temperature rise of 2C8 (3.6F8). According to some climate model projections, the average atmospheric temperature will likely increase beyond this level, mostly because of our more than 40-year delay in acting to slow atmospheric warming.
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emissions trading
One approach to reducing pollutant emissions has been to allow producers of air pollutants to buy and sell gov- ernment air pollution allotments in the marketplace. For example, with the goal of reducing SO2 emissions, the Clean Air Act of 1990 authorized an emissions trading, or cap-and-trade program, which enables the 110 most pollut- ing coal-fired power plants in 21 states to buy and sell SO2 air pollution rights. Under this system, each plant is annually given a number of pollution credits, which allow it to emit a cer- tain amount of SO2 . A utility that emits less than its allotted amount at one its plants has a surplus of pollution credits. It can use these credits to offset SO2 emissions at its other plants, keep them for future plant expansions, or sell them to other utilities or private citizens or groups. Between 1990 and 2017, this emissions trading program helped to reduce SO2 emissions from power plants in the United States by 79%, at a cost of less than one-tenth of the cost projected by the utility industry, according to the EPA. The 2015 Clean Power Plan gives states the option of allowing power plant companies to use emissions trading to meet the new CO2 reduction standards.
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per capita carbon footprint
A per capita carbon footprint is the average footprint per person in a population.
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weather
the set of physical conditions of the lower atmosphere that includes temperature, precipitation, humidity, wind speed, cloud cover, and other factors that occur in a given area over a period of hours to days. The most important factors in an area’s weather are atmospheric temperature and precipitation.
