Chapter 1 - University of San Diego

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Transcript Chapter 1 - University of San Diego

Chapter 1
Environmental Science - Themes
Environmental Science - Definitions
Human Dimensions
Rich and Poor Countries
Science is the Key to Understanding our
The Process of Science
Approaches to Thinking
Historical Context
Learning Outcomes – Chapter 1
After studying this chapter, you should be able to answer the
following questions:
• Describe several important environmental problems facing the
• List several examples of progress in environmental quality.
• Explain the idea of sustainability and some of its aims.
• Why are scientists cautious about claiming absolute proof of
particular theories?
• What is critical thinking, and why is it important in
environmental science?
• Why do we use graphs and data to answer questions in
• Identify several people who helped shape our ideas of resource
conservation and preservation—why did they promote these
ideas when they did?
What is Environment ?
Circumstances and conditions that surround
an organism or group of organisms
Social, cultural, bio-physical conditions that
affect an individual or community
Environmental Science is the systematic
study of our environment and our place in it
Highly interdisciplinary
Applied science
Environ. Sci. draws from many fields to understand and solve problems
Figure 1.2
Crises and Opportunities
• Over 7 billion people on Earth;
• Adding about 80 million more
each year
• Present trends project a world
population between 8 and 10
billion by 2050
• The impact of so many people
on our natural resources and
ecological systems strongly
influences many of the other
problems we face
Figure 1.5
Our Planet Has an Amazingly Rich
Diversity of Life
Millions of remarkable and intriguing species
populate the Earth and help sustain its environment
as well as human inhabitants
This vast multitude of life creates complex,
interrelated communities
But much of this biodiversity
is threatened by extinction
from direct and indirect
human activities
Figure 1.4
Environmental and Political Challenges:
E.g., Climate Change
• Human activities have
greatly increased CO2
other atmospheric
“greenhouse” gases over
the last 200 years
• Climate models indicate
that by 2100, global mean
temperatures could warm
between about 2° and
– warmer than any time
since human civilization
Figure 1.6a
Carbon Dioxide & Climate Change
Causes of Climate Change
1958 - Charles Keeling
starts to measure CO2
atop Mauna Loa
Pre-Industrial CO2
is ≈280 ppm
2015 = 400 ppm !
A 43% increase !
Sources of Anthropogenic CO2
Temperature variation (°C)
CO2 concentration (ppm)
CO2 is one of several atmospheric gases that is transparent to visible sunlight but
absorbs infrared radiation from Earth (glass does this too = greenhouse effect!)
1960 1965 1970 1975 1980 1985 1990 1995 2000 2005
Many Global Challenges Are Addressable With a
Greater Understanding of Environmental Science
• Over the past century,
global food production has
increased faster than
human population growth,
but hunger remains a
chronic problem
• At least 60 million people
face acute food shortages
due to weather, politics/war,
and poor farming practices
Figure 1.6 b
Clean Water
• 1 billion people lack
access to safe drinking
• Every year polluted water
contributes to the death
of more than 15 million
• 40 percent of people live
in countries where water
demands now exceed
Figure 1.6 c
Air Quality
• Air quality has worsened dramatically in many
areas, especially China and India
• Nobel laureate Paul Crutzen estimates that at
least 3 million people die each year from
diseases triggered by air pollution
• Worldwide, the United Nations estimates that
more than 2 billion metric tons of air pollutants
(not including carbon dioxide or wind-blown soil)
are released each year
Energy Resources
• Fossil fuels (oil, coal, and natural gas) presently
provide around 80 percent of the energy used in
industrialized countries
• Easily accessible supplies of these fuels are
diminishing, and there are many problems
associated with their acquisition and use
• Investing in renewable energy and energy
conservation measures could give us cleaner,
less destructive options
Biodiversity Loss
• Habitat destruction, over hunting, pollution, and
introduction of exotic organisms are eliminating
species at a rate comparable to the great extinction
that marked the end of the age of dinosaurs
• >10,000 species are now considered threatened –
including more than half of all primates, freshwater
fish, and amphibians. Top predators, including
nearly all the big cats in the world, are particularly
rare and endangered
• At the same time, domestic cat populations have soared
(they kill more than a billion birds in the United States
every year)
“Scientists are currently
monitoring the 6th Extinction,
predicted to be the most
devastating since the 5th
extinction [Cretaceous] that
wiped out the dinosaurs.”
“In what seems like a fantastic
coincidence, but probably no
coincidence at all, the history
of previous mass extinctions is
being recovered just as people
come to realize that they are
causing another one.” EK
Introduced (Alien) Species
Introduced species often bring about drastic changes
to natural communities and ecosystems
Nile perch was introduced into Lake Victoria as a
food fish, but led to extinction of many native fishes
Spread of Zebra mussels
Marine Resources
• More than a billion people depend on seafood as their
main source of animal protein
• Nearly three-quarters of the worlds 441 major fish
stocks are severely depleted & 90% of the large
predatory fish are gone
(World Resources Institute)
Figure 1.6 d
Ocean Pollution
~ 60% of coastal waters had fish advisories due to
toxic chemicals
~ 60% of the world’s coral reefs are threatened by
pollution (> 10% have been lost!)
Tremendous damage is being done to estuaries,
marshes, mangroves and other coastal wetlands
It is extremely difficult to control ocean pollution
and few countries have laws re: ocean pollution
• Ocean Pollution:
million metric tons of trash and litter tossed
from ships into the ocean annually
 Most
coastlines contaminated by oil & pollution
 Harmful
algal blooms increasing
(caused by water pollution primarily)
Red Tides, Green Tides, Brown Tides
Gulf of Mexico’s Dead Zone:
Seasonally ~15,000 km2 of anoxic water
Beach Closures and Human Health Impacts
The Ocean’s Garbage Patches
Charles Moore founded the Algalita Foundation in 1998
after sailing a catamaran from Hawaii, which took him
through the Great Pacific Gyre
“It began with a line of plastic bags ghosting the surface,
followed by an ugly tangle of junk: nets and ropes and bottles,
motor-oil jugs and cracked bath toys, a mangled tarp. Tires. A
traffic cone. Moore could not believe his eyes. Out here in this
desolate place, the water was a stew of plastic crap.”
There is 6 times more plastic
than plankton in this area,
which is more twice the size
of Texas
Signs of Progress:
Population and Pollution
• Pollution has been decreased and the
population has stabilized in most industrialized
countries and even in some very poor countries
where democracy has been established
– Over the past 50 years, the average number of
children born per woman worldwide has
decreased from 5 to 2.5
– The UN Population Division predicts that the
world population will stabilize at about 9 billion by
the year 2050
• The incidence of lifethreatening infectious
diseases like smallpox
and polio have been
reduced sharply in
most countries during
the past century, while
life expectancies have
nearly doubled
Figure 1.7 b
Renewable Energy
• Renewable energy: Encouraging progress is
being made in a transition to renewable energy
– The European Union and China are developing
wind energy, solar, wave and tidal energy, and
improvements in efficiency to cut reliance on
fossil fuels
– At the Copenhagen climate summit in 2009, the
world's wealthiest countries agreed to aid
developing nations in finding alternative energy
Conservation of Forests and Nature Preserves
• Deforestation has
slowed in Asia
• Brazil, which has led
global deforestation
rates for decades, is
working to protect
• Nature preserves and
protected areas are on
the increase
Figure 1.7 d
Protection of Marine Resources
• Protecting fish nurseries
represents an altogether
new approach to
protecting marine
• Marine reserves are
being established in
California, Hawaii, New
Zealand, and Great
Figure 1.7 c
Signs of Progress:
Information and Education
Literacy and access to education are
expanding in most regions of the world
The Internet makes it easier to share
environmental solutions
Expanding education for girls is driving
declining birth rates worldwide