Introduction to
Environmental Engineering
By James R. Mihelcic and Julie B. Zimmerman
Contributors:
Martin T. Auer
David W. Hand
Richard E. Honrath, Jr.
Alex S. Mayer
Mark W. Milke
Michael R. Penn
Judith A. Perlinger
Noel R. Urban
Brian E. Whitman
Qiong Zhang
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Chapter 1. Engineering & Sustainable Development
James R. Mihelcic and Julie B. Zimmerman
This chapter presents definitions of sustainable development and a review of the global
history of the past few decades on sustainability. Several emerging issues related to
population, urbanization, water, energy, health, and the built environment are reviewed
that will pose challenges and opportunities for engineers in the future.
Major Sections
1.1 introduction and background
1.2 defining sustainability
1.3 issues that will affect engineering practice in the upcoming decades
1.4 the sustainability revolution
Learning objectives
1. Identify ten emerging environmental issues that have a local and global
significance.
2. Define sustainable development (and sustainable engineering) in your own words
and the words of others.
3. Begin to re-define engineering problems in a balanced social, economic, and
environmental context.
4. Relate the Limits to Growth, Tragedy of the Commons, and the definition of
carrying capacity to sustainable development.
5. If you could "talk" to an engineer in a developed country, what would you say to
them, presuming you were born into a developing country and your
community’s health and prosperity are threatened by the global climate changes
caused by anthropogenic CO2 emissions generated primarily by developed
countries and a large number of children in your country die before the age of 5.
6. Define the eight Millennium Development Goals and targets set forth by the
global community.
7. As an engineer who has dedicated your career to help achieve one of the
Millennium goals, identify the one that you would choose and discuss how you
would go about helping to achieve that goal.
8. Relate each of the eight Millennium Development goals to engineering practice.
9. Identify the types (and magnitude) of environment risk that exist for people living
in the developing world.
10. Integrate drivers of global change (such as population, urbanization, land use, and
climate) with engineering solutions.
11. Relate issues of population growth, urbanization, health, sanitation, water
scarcity, water conflict, energy consumption, climate, toxic chemicals, material
use, and the built environment to engineering practice and sustainable
development.
12. Familiarize yourself with Internet resources related to global issues of
sustainability, the environment, and health.
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13. Understand the historical context of the sustainability revolution and how
commonly used vocabulary will change during this revolution.
1.1 Introduction
Engineers play a crucial role in improving living standards throughout the world. As a
result, engineers can have a significant impact on progress towards sustainable
development
World Federation of Engineering Organizations
The environmental movement in the United States began in earnest in the late 1960’s and
early 1970’s with the creation of the Environmental Protection Agency. This
consolidated in one agency a variety of federal research, monitoring, standard-setting and
enforcement activities, as well as the passing of key environmental regulations such as
the National Environmental Protection Act (NEPA), the Clean Air Act, the Water
Pollution Control Act, and the Endangered Species Act. These acts were designed to
address glaring environmental challenges such as the Cuyahoga River catching on fire in
1969 and the toxic waste and subsequent health problems in neighborhoods such as Love
Canal, Niagara Falls, New York.
While we have made tremendous strides in addressing the most egregious environmental
insults and maintained a growing economy, the environmental challenges of today are
more subtle and more complex. They have clear connections between air, land, and
water emissions and come from highly-distributed sources. We also have a much higher
level of understanding of the linkages between society, the economy and the
environment. In this case, scientific, technological, and policy innovations are
recognized as powerful tools in advancing these areas for mutual benefit.
Box 1-1. Rachel Carson and the Modern Environmental Movement
Rachel Carson is considered one the leaders of the modern environmental movement. She
was born 15 miles northeast of Pittsburgh in 1907. Educated at the undergraduate and
graduate levels in science and zoology, she first worked for the government agency that
became the U.S. Fish and Wildlife Service. As a scientist, she excelled at communicating
complex scientific concepts to the public through clear and accurate writing. She wrote
several books including: The Sea Around Us (first published in 1951) and Silent Spring
(first published in 1962). Silent Spring was a commercial success soon after its
publication. It visually captured the fact that songbirds were facing reproductive failure
and early death because of manufacturing and prolific use of chemicals such as DDT that
had bioaccumulated in their small bodies. Some historians believe that Silent Spring was
the initial catalyst that lead to the creation of the modern environmental movement in the
U.S. along with the U.S. Environmental Protection Agency.
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Rachel Carson at Hawk Mountain (Pennsylvania) (photograph taken ca 1945 by Shirley
Briggs, courtesy of the Lear/Carson Collection, Connecticut College).
It is through new scientific, technological, and policy innovation that we can maintain
economic prosperity as well as improve the quality of life for our citizens. This goal of
creating and maintaining a prosperous society needs to be met without the negative
impacts that have historically occurred to our natural resources, the environment, and
communities. This requires a new perspective and new understanding of the
environmental damages that have been traditionally associated with development.
As Albert Einstein stated, “We can't solve problems by using the same kind of thinking we
used when we created them.” It is through this new awareness of sustainability that we
can simultaneously advance society, the environment, and the economy for the long-term
prosperity of future generations. Engineers, in particular, have a unique role to play as
they have a direct affect on the design and development of manmade products, processes
and systems, and subsequently their impacts on natural systems through material
selection, project siting, and end of life handling.
Background
The world's population has exceeded 6 billion with 80 million people added each year.
Resource consumption per capita is also on the rise. For example, over 25% of the
possible terrestrial and aquatic solar energy captured in photosynthesis by primary
producers (i.e., plants, cyanobacteria) is now appropriated by human beings. Just two
more doublings of the human impact on the world’s natural resources (through a
combination of population increase and consumption-fueled economic growth) would
result in 100% of the net primary production being utilized by humans. This ecological
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impossibility would leave ecosystems with nothing. The results could also have
catastrophic implications for humans because of our well-established reliance on
ecosystems for economic prosperity and health (Daly, 1986).
As the world’s population and per capita consumption increases, so does the urgency for
engineers to protect and enhance the environments and communities in which people
reside. This, however, will present numerous challenges to engineers. The United
Nations Environment Programme (UNEP) lists ten existing or emerging
environmental issues (Table 1-1). Engineers are (or soon will be) engaged in developing
sustainable solutions for all these issues.
Table 1-1. Existing and Emerging Environmental Issues (UNEP, 2002).
1. Globalization, trade & development
2. Coping with climate change & variability
3. The growth of megacities
4. Human vulnerability to climate change
5. Freshwater depletion and degradation
6. Marine and coastal degradation
7. Population growth
8. Rising consumption in developing countries
9. Biodiversity depletion
10. Biosecurity
1.2 Defining Sustainability
If you Google the words sustainability, sustainable development, and sustainable
engineering you will get over 300 definitions. Try it! This is one thing that makes
grasping sustainability difficult for some.
Sustainable engineering is defined as the design of human and industrial systems to
ensure that humankind’s use of natural resources and cycles do not lead to diminished
quality of life due either to losses in future economic opportunities or to adverse impacts
on social conditions, human health, and the environment (Mihelcic et al., 2003)
Note that in this definition, issues of the environment, economy, and society (i.e., the
triple bottom line) are integrated for sustainability. The incorporation of the triple
bottom line is common in most definitions along with meeting the needs of current and
future generations. This definition, unlike many in the sustainability literature, explicitly
describes a role for engineers by highlighting the design of human-made systems.
Worldwide, numerous discussions have taken place over the past several decades,
yielding significant contributions to the concept of sustainability. Young engineers
should understand the historical context of these discussions. The United Nations (U.N.)
Conference on the Human Environment (Stockholm, 1972), for example, is significant
because for the first time, it added the environment to the list of global problems.
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As evidence, Principle 1 of the Stockholm Declaration states “Man has the fundamental
right to freedom, equality, and adequate conditions of life, environment of quality that
permits a life of dignity and well-being, and he bears a solemn responsibility to protect
and improve the environment for present and future generations.”
Principle 2 states “The natural resources of the earth including air, water, land, flora,
and fauna and especially representative samples of natural ecosystems must be
safeguarded for the benefit of present and future generations through careful planning
and management, as appropriate.”
Discussion Topic: How is the discipline of environmental engineering grounded in
these two principles?
Box 1-2. Tragedy of the Commons
The “Tragedy of the Commons” describes the relationship where individuals or
organizations consume shared resources (i.e., freshwater; fish from the ocean) and then
return their wastes back into the shared resource (i.e., air, land). In this way, the
individual or organization receives all of the benefit of the shared resource but distributes
the cost across any one who also uses that resource. The tragedy arises when each
individual or organization fails to recognize that every individual and organization is
acting in the same way. It is this logic that has led to the current situation in ocean
fisheries, the Amazon rainforest, and global climate change. In each case, the
consumptive behavior of a few has led to a significant impact on the many and the
destruction of the integrity of the shared resource.
The “Stockholm Conference” also resulted in the creation of the U.N. Environment
Programme (UNEP). See www.unep.org to learn more about this organization and
global environmental problems.
The stated mission of the U.N. Environment Programme (UNEP) is “to provide
leadership and encourage partnership in caring for the environment by inspiring,
informing, and enabling nations and peoples to improve their quality of life without
compromising that of future generations”
Also in 1972, an influential book was published as the outcome of meetings held by the
“Club of Rome”. The Club of Rome formed in 1968 as a group of thirty individuals from
ten countries who wanted to discuss the present and future predicament of the human
race. The book, The Limits to Growth (Meadows et al., 1972) warned of the limitations
of the world’s resources and pointed out there might not be enough resources remaining
for the developing world to industrialize. In the Limits to Growth the authors used
mathematical models to demonstrate that “the basic behavior mode of the world system is
exponential growth of population and capital, followed by collapse.”
Carrying capacity refers to the upper limit to population or community size (e.g.,
biomass) imposed through environmental resistance. In nature this resistance is related to
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the availability of renewable (e.g., food) and nonrenewable (e.g., space) resources as they
impact biomass through reproduction, growth, and survival.
One solution to the world’s environmental problems is to use technological advances to
solve the issue of dwindling or harder-to-extract resources. However, as demonstrated in
the Limits to Growth, in the past, society has “evolved around the principle of fighting
against limits rather than learning to live with them.” This is demonstrated in Figure 1-1
for the whaling industry. Historically, humans could live within a system of finite
resources. This was because they not only had access to a relatively large amount of
resources and available land, but also had a limited population that produced a limited
amount of pollutants. However, with population increasing and industrial production and
consumption on the rise, this historical trend of a world that can moderate the
environmental impact of humans might not be feasible in the long term. With all this
information in mind, perhaps the question that should be asked is:
Discussion Topic: Is it better to live within a determined limit by accepting some
restrictions on consumption fueled growth?
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Figure 1-1. Limits to growth and technology of the whaling industry. Maintaining
growth in a limited system by advances in technology will eventually result in extinction
for both whales and the whaling industry. As wild herds of whales have been destroyed,
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finding the survivors has become more difficult and has required more effort. As larger
whales are killed off, smaller species are exploited to keep the industry alive. Without
species limits, large whales are always taken wherever and whenever encountered. Thus
small whales are used to subsidize the extermination of large ones. (Payne, 1968).
In 1987 Our Common Future (World Commission on Environment and Development,
1987) was released by the United Nations. This book is also referred to as the
Brundtland Commission report because Ms. Gro Brundtland, a former prime minister of
Norway, chaired the commission. This influential document not only adopted the
concept of sustainable development but also provided the stimulus for the 1992 U.N.
Conference on Environment and Development (i.e., the Earth Summit).
The Brundtland Commission Report defined sustainable development as
“development which meets the needs of the present without compromising the ability of
the future to meets its needs.”
Box 1-3. Sustainable Development and the Public Trust Doctrine
Natural resources held in public trust have been available and open to communities for
centuries. The public trust doctrine, which is customized by each state, seeks to
determine the public’s rights to those areas when conflict arises between public and
private use of property. For example, the public trust doctrine as applied to water
resources and environmental engineering would determine what the appropriate balance
is between public and private use of navigable waters and their shores.
Definitions of sustainability are related to legal arguments on the public trust doctrine.
For example, in Sec. 101 of NEPA (1969) [42 USC § 4331] states that, “The Congress,
recognizing the profound impact of man's activity on the interrelations of all components
of the natural environment, particularly the profound influences of population growth,
high-density urbanization, industrial expansion, resource exploitation, and new and
expanding technological advances and recognizing further the critical importance of
restoring and maintaining environmental quality to the overall welfare and development
of man, declares that it is the continuing policy of the Federal Government, in
cooperation with State and local governments, and other concerned public and private
organizations, to use all practicable means and measures, including financial and
technical assistance, in a manner calculated to foster and promote the general welfare, to
create and maintain conditions under which man and nature can exist in productive
harmony, and fulfill the social, economic, and other requirements of present and future
generations of Americans.”
Discussion Topic: Can you see the relationship between this legal argument and the
definition of sustainable development proposed by the Brundtland Commission?
Discussion Topic: Investigate the public trust doctrine as it applies to the public’s
access to navigable waters and shores in your state. What type of access is legally
guaranteed to people who fish, boaters, and beach users?
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The 1992 Earth Summit (held in Rio de Janeiro) was the first global summit that
specifically addressed the environment. It also integrated for the first time environmental
and economic issues. One outcome of the “Rio Summit” was the 800-page, nonbinding
Agenda for the 21st Century (i.e., Agenda 21) that set forth goals and recommendations
related to environmental, economic, and social issues. In addition, the U.N. Commission
on Sustainable Development was created to oversee implementation of Agenda 21. The
complete document is available at the UNEP website (www.unep.org).
At the 2002 World Summit on Sustainable Development (Johannesburg), world leaders
reaffirmed the principles of sustainable development adopted at the Earth Summit ten
years earlier. One outcome was development of Millennium Development Goals
(MDGs) (see Table 1-2). The MDGs are an ambitious agenda for reducing poverty and
improving lives based on what world leaders agreed upon at the Millennium Summit in
September 2000. For each goal one or more targets have been set, most for 2015, using
1990 as a benchmark. While these goals are lofty and far-reaching, the follow up
commitments including financial and human capital are uncertain at this time.
Table 1-2. The eight Millennium Development Goals (MDGs) including background
material and target goals. MDGs are an ambitious agenda embraced by the world
community for reducing poverty and improving lives of the global community. Learn
more at: www.un.org/millenniumgoals/
Millennium Development Goal
(Background)
1) Eradicate extreme poverty and hunger
(More than a billion people still live on
less than US$1 a day)
2) Achieve universal primary education
(As many as 113 million children do not
attend school)
Target(s)
3) Promote gender equality and empower
women (Two-thirds of illiterates are
women, and the rate of employment
among women is two-thirds that of men)
Targets for 2005 and 2015: Eliminate gender
disparities in primary and secondary education
preferably by 2005, and at all levels by 2015.
4) Reduce child mortality (Every year
nearly 11 million young children die
before their fifth birthday, mainly from
preventable illnesses)
5) Improve maternal health (In the
developing world, the risk of dying in
childbirth is one in 48)
6) Combat HIV/AIDS, malaria, and other
diseases (40 million people are living
with HIV, including 5 million newly
Target for 2015: Reduce by two thirds the
mortality rate among children under five.
Target for 2015: Halve the proportion of people
living on less than a dollar a day and those who
suffer from hunger.
Target for 2015: Ensure that all boys and girls
complete primary school.
Target for 2015: Reduce by three-quarters the
ratio of women dying in childbirth.
Target for 2015: Halt and begin to reverse the
spread of HIV/AIDS and the incidence of
malaria and other major diseases.
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infected in 2001)
7) Ensure environmental sustainability
(More than 1 billion people lack access to
safe drinking water and more than 2
billion people lack sanitation.
8) Development of a Global Partnership
for Development
• Integrate the principles of sustainable
development into country policies and
programs and reverse the loss of environmental
resources.
• By 2015, reduce by half the proportion of
people without access to safe drinking water.
• By 2020 achieve significant improvement in
the lives of at least 100 million slum dwellers.
• Develop further an open, rule-based,
predictable, non-discriminatory trading and
financial system.
• Address the special needs of the least
developed countries.
• Address the special needs of landlocked
countries and small island developing States.
• Deal comprehensively with the debt problems
of developing countries through national and
international measures in order to make debt
sustainable in the long term.
• In co-operation with developing countries,
develop and implement strategies for decent
and productive work for youth.
• In co-operation with pharmaceutical
companies, provide access to affordable,
essential drugs in developing countries.
• In co-operation with the private sector, make
available the benefits of new technologies,
especially information and communications.
Regardless, the eight MDGs as policy goals, present a vision of a better world that can
serve to guide engineering innovation and practice for the next several decades. They
represent commitments to reduce poverty and hunger, and to tackle ill health, gender
inequality, lack of access to clean water, and environmental degradation. This is a good
example of the link between policy and engineering and how policy can drive
engineering innovation and new engineering advancements can encourage the
development of policies with advanced standards redefining “best available
technologies”.
1.3 Issues that will affect engineering practice in the upcoming decades
As noted in the previous section, during the past 40 years, there has been increased
attention on global sustainability with a growing consensus that the world faces serious
challenges in terms of long-term economic growth, societal prosperity, and
environmental protection. These challenges arise from current scientific, technical and
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policy approaches as well as the behavior of individuals, communities, corporations, and
government.
While there is on-going debate on the major challenges to sustainability, most engaged in
these discussions would suggest that engineering systems related to water, climate and
air, sanitation, waste management, health, energy, food production, chemicals/materials,
and the built environment, are at the forefront. These issues pose local and global
challenges that uniquely affect communities located in every part of the world. The
problems with these issues are closely related to population and demographics. Solutions
to these issues will require an integrated approach that combines technology, governance,
and economics. From this, it is clear that with an understanding of these broader issues,
current engineering design can be engaged more effectively to advance the goal of local,
regional, and global sustainability. This section provides an overview of some challenges
that engineers will face in the upcoming century.
1.3.1 Population & Urbanization
The global population of 6 billion people is expected to reach 9-10 billion people during
this century (Figure 1-2). The impact of population growth has long been understood as
one of the grand challenges to mutually advancing environmental, economic, and societal
goals and creating a sustainable future. It also has a great impact on how one manages
natural resources and designs and invests in engineering infrastructure. The vast majority
of population growth is occurring in the developing world (especially in urban areas)
while population is stagnant, and in some cases declining, in some parts of the
industrialized world.
Figure 1-2. Global population from 1750-2000 and projected increases to 2050.
Increases in the population are attributed to more and less developed countries. For the
first time in human history, urban population exceeds rural population and most of the
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population growth expected over the next century will be added to urban environments
(United Nations, 2006).
Box 1-4. Defining Developed and Developing Countries
While there is no single definition of a developed country, the generally accepted concept
refers to countries that have reached relatively high levels of economic achievement
through advanced production, increased per capita income and consumption, and
continued utilization of natural and human resources. In common practice, Japan in Asia,
Canada and the United States in North America, Australia and New Zealand in Oceania,
and most countries in Northern Europe and Western Europe are considered developed
countries.
A developing country is one that has not reached the stage of economic development
characterized by the growth of industrialization. In developing countries, the national
income is less than the amount of money needed for basic infrastructure and human
services leading a relatively low standard of living, an undeveloped industry base, and
substandard per capita income.
This may suggest that within the complexities of growing population that include birth
and mortality rates, socio-political pressures, access to health care and education, gender
equality, and cultural norms, there is an empirical correlation between the rate of
population growth and level of economic development, often equated with quality of life.
This relation means that one approach to meet the challenges of stabilizing population
growth and advancing the goal of sustainability is through improved quality of life and
expanded development that is equitable and thus sustainable. Historically, however,
increases in development and quality of life have been inextricably linked with
consumption and associated resource depletion and environmental degradation. There is
a significant amount of evidence that suggests that an increasing human population places
an increasing strain on natural resources as the society begins to develop its
infrastructure. The opportunity for the engineering community is to bring about
continued development and enhanced quality of life through the protection and
restoration of ecosystems and the design, development, implementation, and maintenance
of infrastructure that does not have the historical consequences of environmental
degradation, resource consumption, and adverse and unjust impacts on society.
One issue listed in Table 1-1 was the growth of megacities, i.e., urbanization. For the
first time in human history, urban population exceeds rural population. In fact, by 2030,
61% of the global population is expected to be living in urban areas. It is widely
recognized that urbanization can be an important source of health problems. For
example, 30-60% of the urban population in the developing world lacks adequate sanitary
facilities and drainage systems, and piping for clean water.
1.3.2 Health
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The World Health Organization (WHO) (see www.who.org) estimates that poor
environmental quality contributes to 25% of all preventable ill health in the world. In
addition, the WHO reports that 1.1 billion people do not have access to an improved
water supply. An improved water supply is defined as a household connection, public
standpipe, borehole, protected dug well, protected spring, and rainwater collection.
Bottled water is not considered an improved water supply. Adequate sanitation coverage
is even lower with 2.4 billion lacking access to any type of sanitation equipment. The
ecological impact on surface waters that receive domestic water that has been processed
by households and businesses is great because more than 90% of the wastewater in the
developing countries and 33% in developed countries is not treated (WHO, 1999). This
has lead to dire consequences for downstream communities’ water supplies, and for
fishing communities dependent on aquatic ecosystems for their economic livelihood.
Table 1-3. Distribution of global population not served with improved water supply and
sanitation. Coverage in the U.S. and Canada approaches 100%. (data from the World
Health Organization & United Nations Children’s Fund, Global Water Supply and
Sanitation Assessment 2000 Report).
Region
Asia
Africa
Latin America and
Caribbean
Oceania
Europe
Percentage of
Population Lacking
Improved Water
Supply
19
38
15
Percentage of
Population Lacking
Improved
Sanitation
52
40
22
2000 Population
(in millions)
12
4
7
8
30
729
3,683
784
519
Because many disease-causing vectors are transmitted through contact with water, air,
and solid waste, health issues are clearly critical to the environmental engineering
profession. Health is inextricably linked to sustainable development.
“Health is both a resource for, as well as an outcome of, sustainable development. The
goals of sustainable development cannot be achieved when there is a high prevalence of
debilitating illness and poverty, and the health of a population cannot be maintained
without a responsive health system and a healthy environment. Environmental
degradation, mismanagement of natural resources, and unhealthy consumption patterns
and lifestyles impact health. Ill-health, in turn, hampers poverty alleviation and
economic development” (World Health Organization).
HIV/AIDS, tuberculosis, and malaria are among the world’s largest killers. They all have
their greatest impact on developing nations, interact in ways that make their combined
impact worse, and create an enormous economic burden on families and communities,
especially in those where economic livelihood is dependent on good health (UNESA,
2004). Figure 1-3 shows the types of environmental risk that lead to the greatest loss of
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disability-free days of a person’s life in the world. Much of the burden of this risk is
assumed by people living in the developing world. Note that almost one half of the risk is
associated with poor access to drinking water and sanitation, and much of the other half is
due to exposure to indoor and outdoor air pollution.
46% Unsafe water,
sanitation, and hygiene
33% Indoor air pollution
from use of solid fuels
11% Lead exposure
5% Urban air pollution
5% Global climate change
Figure 1-3. Types of environmental risk that lead to greatest loss of disability-free days
of a person’s life in the world. (data from Ezzati et. al., 2004).
For people living in poverty, illness and disability translate directly into loss of income.
This can be devastating for individuals and their families who are dependent on their
health for household income (WHO). The effects of ill health have significant
ramifications at the macroeconomic scale as well. For instance, a significant portion of
Africa’s economic shortfall is attributed to climate and disease burden.
Environmental degradation can have an even more direct effect on household income.
The income derived from ecosystems (i.e., environmental income) is recognized to
provide a “fundamental stepping stone in the economic empowerment of the rural poor”
(WRI, 2005). This natural capital provided by the environment, is the stock that yields
the flow of natural resources. Some of those resources are renewable (e.g., fish, trees)
and some are non-renewable (e.g., petroleum). Non-renewable natural capital can only
be depleted, while renewable natural capital can either be left alone to regenerate or can
be cultivated with the use of man-made capital (e.g., fish ponds, cattle herds, forest
plantations).
1.3.3 Water Scarcity and Conflict
Of the projected 1 billion new urban dwellers that will be added by the year 2010, most
will be absorbed by developing world cities that already face shortages of potable water
and adequate sanitation. Water scarcity is a situation where there is insufficient water to
satisfy normal human requirements. By one measure, nearly 2 billion people currently
suffer from severe water scarcity. Furthermore, of the additional one billion people
expected to face water scarcity by the year 2025, 20% will be associated with direct
effects of climate change (Vörösmarty et al. 2000). Figure 1-4 describes a few of the
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impacts humans experience as a result of water scarcity and some of the external factors
that can exacerbate these impacts.
Figure 1-4. Impacts and factors exacerbating impacts on humans and the environment
from water scarcity (photo courtesy of James Mihelcic).
A country is defined as experiencing water stress when annual water supplies drop
below 1,700 m3 per person. When annual water supplies drop below 1,000 m3 per person,
the country is defined as water scarce. Figure 1-5 shows the countries currently
experiencing water stress or water scarcity. By the year 2025, more countries will
encounter water scarcity (see Figure 1-5). The water stress indicator in these maps
measures the proportion of water withdrawal with respect to total renewable resources. It
is a criticality ratio, which implies that water stress depends on the variability of
resources. Water stress causes deterioration of fresh water resources in terms of quantity
(over-exploitation of groundwater, dry rivers, etc.) and quality (eutrophication, organic
matter pollution, saline intrusion, etc.).
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Figure 1-5. Countries Facing Water Stress or Scarce Conditions in 1995 and projected
for 2025. (data from World Meteorological Organization and figure adapted from United
Nations Environment Programme, 2007)
Water is also expected to be one of the most pressing global security problems in the
future. For example, the U.S. Intelligence Council reports that “water shortages
occurring in combination with other sources of tension-such as in the Middle East-will be
the most worrisome. As some countries press against the limits of available water
between now and 2015, the possibility of conflict will increase.”
The potential for conflict over freshwater is enormous, given its importance for:
agriculture, industry, domestic use, and energy production. Conflicts arise from the fact
that water does not respect political boundaries. In fact, more than 300 major freshwater
watersheds lie on or across international borders, including the U.S.-Canada and U.S.Mexico borders.
Societal conflict over management of water resources in the U.S. has been popularized in
movies and books such as Chinatown and Cadillac Desert. Conflicts over water
management continue to make the news today, as evidenced several years ago by events
in the Klamath River basin. This “water war” in Oregon drew national attention when
armed federal agents were called in to stop farmers from forcing open the head gates in
the Klamath reclamation system. Across the world, conflicts over water management are
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becoming more frequent and are feared to be the source of conflict in the near future.
Figure 1-6 provides some examples of conflict areas.
Discussion Topic: Research and discuss a specific water conflict in your region or
globally.
Columbia
Basin
Klamath
Basin
U.S.Mexico
Border
Latin
America:
Privatized
Municipal
Systems
Great
Lakes
Rhine
Basin
TigrisEuphrates
Basin
Florida
Everglades
Jordan
Basin
Murray
Basin
Nile
Basin
Figure 1-6. Some areas of the world that experience conflict over water management.
More than 300 major freshwater watersheds lie on or across international borders.
Finding sustainable economic solutions to water infrastructure problems is another
challenge. Privatization of urban water systems is a rapidly increasing trend, but the
political and economic consequences of privatization are not yet understood. In older
U.S. cities, many located in the east, water infrastructure is reaching the end of its
engineered life span. Expenditures on the order of $250 billion over 30 years to $1
trillion over 20 years, may be required in the U.S. alone for the replacement of urban
water distribution systems (Andrews, 2000; AWWA, 2001)
1.3.4 Energy & Climate
U.S. energy consumption in all sectors has increased in the past 30 years and it is
projected to increase in the future (Figure 1-7a). Much of the energy consumption is in
sectors that are designed, constructed, and managed by engineers (e.g., transportation,
residential and commercial buildings). Figure 1-7b shows the breakdown of fuels that
provide electricity in the U.S. and the small percentage of U.S. energy needs currently
(and projected to be) provided by renewable energy sources.
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Figure 1-7a. Delivered energy consumption by sector in the U.S. (quadrillion Btu).
Figure 1-7b. Electricity generation in the U.S. by type of fuel (billion kilowatt hours)
(from DOE, 2006).
Figure 1-8 shows the energy consumption of North America (U.S., Canada, Mexico) on a
per capita basis compared to the rest of the world since 1980. In 2003, North America’s
per capita energy consumption was approximately four times higher than the rest of the
world. This demonstrates that engineers need to be concerned about the source and use
of energy in every decision they make.
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Figure 1-8. Energy consumption per capita in North America compared to the rest of the
world. North America’s energy consumption is approximately four times higher than the
rest of the world over this 23-year period.
Greenhouse gas emissions are causing changes in global climate. The majority of these
emissions are associated with burning of fossil fuels for energy with a smaller amount
associated with land use. The Intergovernmental Panel on Climate Change (IPCC)
(cowinners of the 2007 Nobel Peace Prize!) was established by the World Meteorological
Organization and UNEP to assess scientific, technical, and socio- economic information
related to our better understanding of climate change (for more information, see
http://www.ipcc.ch/). The 2,000+ notable scientists that make up the IPCC predict that
the likely range of temperature increase in the next century is estimated to range from 2.4
to 6.4oC.
Box 1-5. The Two Percent Solution
Some scientists say the most dangerous impacts of global warming can be curbed if
overall emissions are reduced by 80% by the year 2050. This might seem like a lot but it
would only require that everyone cut their carbon dioxide emissions by 2% a year from
now until 2050. If you search on the Internet for key words like “two percent” and
“climate change” you will find how ways you can implement voluntary emission
reductions and be part of the 2% solution.
The consequences for warming for the world and the U.S. will be significant. Figure 1-9
shows the expected impacts in the areas of water, ecosystems, food, coastal areas, and
health as they relate to the specific increase in global mean temperature. Not only are
ecosystems and wildlife heavily dependent on climate but human health and the economy
are as well. The impact of climate change will differ by location. For example, small
island nations and some parts of the developing world will be impacted to a greater
extent, as will particular geographical regions and industrial sectors of the U.S.
Economic sectors that are dependent on agriculture will struggle with more variability in
weather patterns and the insurance industry will have a difficult time responding to more
catastrophic weather events.
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Figure 1-9. Expected impacts from climate change in the areas of water, ecosystems,
food, coasts, and health. The type and extent of the impact will be influenced by the
magnitude of the temperature increases (with permission of Intergovernmental Panel on
Climate Change, Climate Change 2007: Impacts, Adaption and Vulnerability, Summary
for Policymakers, Table SPM.2, 2007).
The U.S. of course has a wide range of climate conditions that engineers have dealt with
for centuries. For example, it is well known that the Southwest is dry and the Northeast
is wetter. These variations in climate have impacted engineering decisions related to
issues of water supply and use resulting with a fixed and manageable infrastructure based
on best practices at the time that is struggling to meet current demand. The nation's
54,000 drinking water systems face staggering public investment needs over the next 20
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years. Although America spends billions on infrastructure each year, drinking water faces
an annual shortfall of at least $11 billion to replace aging facilities that are near the end of
their useful life and to comply with existing and future federal water regulations. The
shortfall does not account for any growth in the demand for drinking water over the next
20 years (ASCE, 2005).
As climate, population, and demographics change in the future, engineers must not only
incorporate technological advances to reduce energy and water usage, but also make use
of renewable sources of energy and materials. Engineers designing infrastructure must
also anticipate future growth, societal behavior, and other factors that impact demand
during the intended lifetime of the infrastructure projects.
Box 1-6. Climate and health
Climate change also has a relationship to human health. Increases in temperature have a
documented relationship to illness and death. Also, the impact on health and
infrastructure from extreme weather events associated with climate change could be
great. Indoor air pollution issues related to spores and mold may also increase and the
vector-borne diseases associated with water and solid waste may also change. For more
information, see www.who.org
1.3.5 Toxic Chemicals and Finite Resources
The use, generation, and release of toxic chemicals to the environment remains a global
issue. In the United States alone, over 4 billion pounds of toxic chemicals were released
by industry into air, land, and water in 2004, including 72 million pounds of recognized
carcinogens, according to US EPA’s Toxics Release Inventory. Persistent organic
pollutants (POPs) and other toxic chemicals including endocrine disruptors, are of
serious concern globally. As these chemicals cycle through natural and human systems,
they pose significant risks to both ecosystem function and human health because humans
are exposed to these chemicals through breathing air, drinking water, and eating food.
This is especially important for susceptible populations such as children, pregnant
women, and the elderly.
Engineers can play a significant role in reducing the risks associated with the use and
generation of these chemicals. Ideally, engineers can achieve this by designing products,
processes, and systems that do not specify these chemicals in production, repair,
operation, and maintenance. Another important contribution engineers can make is to
understand the fate and transport of these chemicals so that damage to natural systems
and exposure to humans can be eliminated or minimized.
When it comes to materials, another concern beyond toxicity is our current reliance on
non-renewable resources, which will only grow in magnitude as the population
increases. A renewable resource is any natural resource that is depleted at a rate slower
than the rate at which it regenerates or is unlikely to be depleted in the conceivable
future. It has been stated that in order for the current population of the Earth to live at the
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same quality of life as we do in America, it would require the resources of four planet
Earths (Rees, 2006).
Engineers can contribute to meeting this challenge in several ways. The first is to
incorporate renewable resources into designs and specifications. The second is to design
products, processes, and systems for high material efficiency reducing the amount of
material acquired, manufactured, and then subsequently wasted. There is also significant
opportunity to improve our current material efficiency. Recent analysis has found that of
all raw materials used in manufacturing processes 94% ends up as waste and only 6% end
up in the product! In addition, 99% of the original material used in the production of, or
contained in, goods made in the U.S. become waste within six weeks of sale (Lovins,
1997). The majority of those discarded materials are from non-renewable resources,
particularly petroleum, which adds to environmental and human health impacts.
1.3.6 Material Flows and the Built Environment
The built environment (see Chapter 14) “includes everything that is 'built' - all types of
building, such as houses, shops, offices, factories, schools, churches, together with civil
engineering works such as roads, railways, runways, bridges and harbors” (SA, 2005).
While only 2-3% of North America’s land area is built on, approximately 60% of this
land area is now impacted by the built environment (UNEP, 2002). The built
environment also requires a tremendous amount of water, energy, and natural resources
for its construction and operation.
An analysis of materials flow in the U.S. (Figure 1-10) shows that approximately 6/7’s
of the U.S. material flow by weight is associated with items such as aggregate, cement,
steel reinforcement, and wood. All these materials are incorporated into engineering
infrastructure. (Note that water is not included in this analysis but would be the single
largest material flow if included.)
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.
Figure 1-10. Flow of raw materials in the U.S. by weight (1900-1998). The use of raw
materials has increased extensively in the 20th century and much of it is used in the civil
engineering profession in term of aggregates, cement (which is included in industrial
minerals), and steel reinforcement (which is included in primary metals) (from U.S.
Geological Survey, Wagner, 2002).
Aggregates are used in foundations and in production of concrete. Industrial materials
include Portland cement and wallboard used in residential and commercial construction.
The embodied energy (the amount of energy required in the lifecycle stages of
acquisition of raw materials, manufacturing, use, and end of life) of concrete (made up of
cement, sand, stone, and water) has a significant impact on our current energy flows
(Table 1-4). The transportation of aggregates and cement to job sites accounts for over
10% of the total embodied energy. In addition, production of 1 lb of Portland cement
results in production of approximately 1 lb of CO2. When considering the “end of life”
stage for the life cycle of engineering materials, 13-19% of solid waste is construction
and demolition debris, one half of this is concrete (by volume), and only 20-30% of this
material is recycled (Horvath, 2004).
Table 1-4. Embodied energy associated with components of concrete (Horvath, 2004,
reprinted with permission from Annual Review of Environment and Resources, Volume
29, ©2004 by Annual Reviews, www.annualreviews.org)
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Material
Cement
Sand
Crushed stone
Water
% material by weight
12
34
48
6
% of embodied energy
94
1.7
5.9
0
The built environment also impacts the local heating of urban areas (termed the urban
heat island) as well as the quantity and quality of water that cycle through it. Figure 111 shows the intensity of land use around the world. Many highly urbanized watersheds
are located along the east coast of the U.S. and similar land use intensity in Western
Europe and Japan. There are less dense urban concentrations in the remainder of the U.S.
and coastal areas of China, India, Central America, and the Persian Gulf.
Figure 1-11. Urban and Industrial Land use by River Basins in the world. Highly
urbanized watersheds are concentrated along the east coast of the United States, Western
Europe, and Japan. Lesser urban and industrial land use occurs in coastal China, India,
Central America, most of the United States, Western Europe, and the Persian Gulf.
(redrawn with permission of World Resources Institute, 2000. Pilot Analysis of Global
Ecosystems (PAGE): Freshwater systems. World Resources Institute, Washington, DC).
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These urban areas were built up by changing and removing rivers, lakes, forests, and
wetlands. This has had great impact on the infiltration properties, transpiration rates, and
associated runoff from these watersheds. Impervious surfaces (discussed in Chapters 8
and 14) that cover our roads increase not only the volume, but also the rate at which
water runs off. This has adversely impacted the recharge of groundwater resources as
well as the quality of receiving water bodies. Loss of wetlands in these areas has
exacerbated the effects.
There are also challenges related to moving out from urban centers and creating suburban
developments – also known as “sprawl”. This type of growth requires significant
material and energy to develop and maintain, causes people to commute greater distances
often in personal cars rather than on public transit, and can contribute to the
fragmentation of communities and wilderness and open space. One strategy to mitigate
the growing concerns with sprawl is through strategies such as Smart Growth or New
Urbanism. Both of these approaches to urban development are focused on designing
communities that preserve natural lands, protect water and air quality, and reuse alreadydeveloped land. By designing mixed-use neighborhoods (i.e., residential, shops, offices,
schools), communities are creating situations where residents can walk or bike, use public
transportation, and drive their car, if they choose, with a focus on living and working
within the same community. The high quality of life in these communities makes them
economically competitive, creates business opportunities, and improves the local tax base
(USEPA, 2007).
1.4 The Sustainability Revolution
Society and the engineering community are at the onset of a new revolution, the
sustainability revolution. This revolution is one of several, occurring over the past
10,000 years that have changed how humans interact with natural systems. The first two
were the agricultural and industrial revolutions. These two revolutions did not take place
over a few years, but over many decades and centuries. Given this timeframe, though
the pressures on the environment may be greater because of population and technology,
we are at the relatively beginning of this newest revolution.
When the agricultural revolution began 10,000 years ago, human population was
approximately 10 million. By the year 1750 the world’s population had grown to an
estimated 800 million. An agriculture-based society was not necessarily more
productive or efficient. In fact, some believe it was simply the basis to accommodate
increasing population. For example, the agriculture revolution resulted in food of a lower
nutritional value on a per acre basis; however, it limited challenges to wildlife and
wilderness. The agricultural revolution also brought forward concepts of land ownership,
feudalism, wealth, status, trade, money, power, guilds, temples, armies, and cities
(Meadows et al., 2004).
Over the relatively recent time frame of the industrial revolution, the global population
increased to over 6 billion individuals. The industrial revolution brought us machines,
capitalism, roads, railroads, combustion, smokestacks, factories, and large urban areas. It
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and the agricultural revolution also brought the world the list of current and emerging
environmental issues listed previously in Table 1-1.
The industrial revolution was also the basis for adding to our vocabulary what are now
commonly used words to describe many modern environmental challenges and
opportunities. Table 1-5 lists some of those words that have become common vocabulary
during the industrial revolution. It also provides a list of words that will be commonly
used during the sustainability revolution.
Table 1-5. Vocabulary that became commonplace as an aftermath of the industrial
revolution and vocabulary that is becoming common during the sustainability revolution.
Industrial Revolution
non-renewable energy
waste
climate change
consumption
accumulation
toxicity, smog, persistence organic
pollutants, endocrine disrupters
transportation
concrete hydraulic channels
urban heat island effect
bioaccumulation
industrial design
gross national product (GNP)
Sustainability Revolution
renewable energy
Efficiency
ecological restoration
resource equity
social and environmental justice
green chemistry
Accessibility
low impact storm water development, rain
gardens
green roofs
biodiversity
green design
index of sustainable economic welfare,
environmental sustainability index, genuine
progress indicator
Engineers can significantly contribute to the success of the sustainability revolution
through their power and potential to the design and manage the future through innovative,
sustainable design. By thinking beyond incremental improvements to leap-frog
technologies, by providing services without physical entities, by designing and
engineering with intent, engineers can play a significant role in achieving a sustainable
future. As discussed earlier, Einstein said that a new level of awareness was needed to
create solutions – in this case, to design a better tomorrow.
Keywords
built environment, Brundtland Commission, carrying capacity, climate, developed
country, developing country, embodied energy, energy consumption, environment,
economy, & society (the triple bottom line), environmental income, greenhouse gas,
health & sustainable development, improved water supply, Intergovernmental Panel on
Climate Change (IPCC), land use, Limits to Growth, materials flow, Millennium
Development Goals, new urbanism, nonrenewable resources, population growth, public
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trust doctrine, Rachel Carson, renewable resources, smart growth, sustainability,
sustainable development, sustainable engineering, sustainability revolution, toxic,
Tragedy of the Commons, United Nations Environment Programme (UNEP),
urbanization, urban heat island, water conflict, water scarcity, water stress, World Health
Organization (WHO)
Problems
1-1. Identify 3 definitions of sustainability from 3 different sources (i.e., local, state or
Federal government; industry; environmental organization; international organization;
financial or investment organization, etc.) and compare and contrast them with the
Brundtland Commission definition. How do the definitions reflect the source that they
come from?
1-2. Write your own definition of sustainable development as it applies to your
engineering profession. Explain the appropriateness and applicability. (maximum 2-3
sentences).
1-3. Presume you were born into a developing country. Your community’s health and
prosperity are threatened by climate changes caused by anthropogenic CO2 emissions
generated primarily by developed countries. This situation is so extreme that people in
your community do not name their children until they live past 5 years old, since many
die before that age. If you had a chance to"talk" to an engineer in a developed country,
what would you say?
1-4. Research the progress towards meeting each of the eight Millennium Development
Goals (MDGs) in two countries of your choice. Summarize in a table any progress made
towards meeting specific goals. (www.un.org/millenniumgoals/).
1-5. Research two examples of persistent organic pollutants (POPs) and write a short
paragraph that describes the chemical, the most common use/application of the chemical,
and known or suspected impacts to human health and the environment. What are some
economic, societal, and environmental issues associated with your chemicals?
1-6. Construct a plot that shows population on the y axis (since 1960) and on the x axis
lists major global conferences related to the environment and sustainability. Also add
any major global events (e.g, disaster, war, famine, etc) that you believe have contributed
to the loss of environmental or social attributes that you personally value.
1-7. Relate the “Tragedy of the Commons” to a local environmental issue. Be specific on
what you mean in terms of the “commons” for this particular example, and carefully
explain how these “commons” are being adversely impacted for current and future
generations.
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1-8. Research a current global environmental problem at www.unep.org. What is the
current state of the environmental resource associated with the problem? Are any future
projections provided? If so, what are they?
1-9. At www.unep.org, there are many graphs that depict environmental issues on a
global scale. Select one graph that is related to one of the issues discussed in Section 1.3.
Re-produce this graph and discuss how different regions of the world (North America,
Central America & Caribbean, South America, Europe, Asia, Oceania) are affected by
this particular issue. How might future issues of population growth, urbanization, and
climate change impact this issue (positively or negatively). Present a sustainable solution
to the problem that includes a balance of societal, environmental, and economic issues.
1-10. Research the World Health Organization web site (www.who.org) and write a onepage essay on how health and sustainability are linked together. Provide some specific
examples.
1-11. Familiarize yourself with the web site of the Intergovernmental Panel on Climate
Change (IPCC) (http://www.ipcc.ch/). Write a short 1-page essay on how changes in
climate will impact two aspects of your engineering profession in the future.
1-12. Research a water conflict issue from the U.S. and outside the U.S. What
similarities and differences do you see between each conflict?
1-13. Identify a watershed that crosses state or national boundaries and is close to your
university/college. What are some possible conflicts over management of this
watershed? Identify at least 3 stakeholders.
1-14. Go to www.doe.gov and research energy consumption in the household,
commercial, industrial, and transportation sectors. Develop a table on how this specific
energy consumption relates to the percent of U.S. and global CO2 emissions? Identify a
sustainable solution for each sector that would reduce energy use and CO2 emissions.
1-15. Go to www.epa.gov and research “smart growth” or “urban heat island”. Write a
one-page essay that defines your topic and importantly, relates it to engineering practice.
1-16. Research the definition of “civil society” on the United Nations web page (see
www.un.org). Discuss why members of civil society should be actively engaged in a
sustainable solution to a common problem that engineers work on in your community.
(e.g., water quality, air quality, transportation, accessibility, land use).
1-17. Go to www.asce.org and research and discuss the state of infrastructure in the U.S.
1-18. Research a health issue at www.who.org that is related to water, indoor air, or
climate. In one-page, discuss the issue and provide your own sustainable solution to
solving this problem that includes societal, environmental, and economic components.
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1-19. In your own words, write in one paragraph how health and sustainability are
related. Does your discussion differ if you were living in the developed or developing
world? What is unhealthy about current transportation systems?
1-20. Go to the World Resources Institute (www.wri.org) and access the report, World
Resources 2005: The Wealth of the Poor – Managing Ecosystems to Fight Poverty.
Select one case study and demonstrate how people living in poverty depend on the
environment for a substantial portion of their economic livelihood. Be specific on the
actual amount of economic wealth the environment provides in this study.
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