Grotzinger • Jordan
Understanding Earth
Sixth Edition
Chapter 23:
THE HUMAN IMPACT ON
EARTH’S ENVIRONMENT
© 2011 by W. H. Freeman and Company
Chapter 23
The Human
Impact on
Earth’s
Environment
About Human Impact
• Human population is immense and
resources are being consumed at an
astounding rate.
• Balancing resource usage versus
environmental protection is
challenging.
• It remains to be seen if we can use our
resources for sustainable
development.
Lecture Outline
1. Civilization as a global geosystem
2. Fossil-fuel resources
3. Alternative energy resources
4. Global change
Lecture Outline
5. Earth system engineering and
management
1. Civilization as a Global Geosystem
• Civilization exists at the thin
interface between the climate,
plate tectonic, and geodynamic
systems.
• Human civilization has
profoundly altered the planet,
especially in the last 200 years.
1. Civilization as a Global Geosystem:
Human Population Growth
1. Civilization as a Global Geosystem
• Human population increase
now doubles every 47 years.
• Humans now alter the global
environment on a scale that
is staggering compared to
natural processes.
1. Civilization as a Global Geosystem
● Example of human’s changes
● one third of forests cleared
● humans move more soil and rock
than all natural processes
● dams and reservoirs now trap 30%
of all river sediments
● coolants have damaged the critical
ozone layer
● carbon dioxide levels up by 40%
1. Civilization as a Global Geosystem
● Natural energy resources
● Renewable energy resources
● biomass (wood burning)
● Non-renewable energy resources
● fossil fuels (oil, gas, coal)
1. Civilization as a Global Geosystem
● Before 1850, most U.S. energy
was from wood burning.
● After 1850: the rise of the U.S.
fossil fuel economy.
● by 1900, coal was ~ 70%
● by 1950, fossil fuel was ~ 90%
1. Civilization as a Global Geosystem
● Global energy consumption
● quad = 1015 Btus
● U.S. in 2004 = 100 quad
● global (2004) = 440 quad
● global (2020) = 600 quad
1. Civilization as a Global Geosystem:
U.S. Energy Consumption
1. Civilization as a Global Geosystem:
U.S. Energy System
1. Civilization as a Global Geosystem:
Projected Energy Consumption
1. Civilization as a Global Geosystem
● Global carbon flux from energy
production
● Huge increase from
natural rates of carbon
transfer
● Carbon economy
● Carbon dioxide is a
greenhouse gas
2. Fossil-Fuel Resources
● Fossil fuel resources and reserves
● Resources – have been
discovered
● Reserves remain in the Earth
2. Fossil-Fuel Resources:
Remaining Nonrenewable World Energy
2. Fossil-Fuel Resources
● How oil and gas forms
● Formed in source beds
● May move to reservoirs
● Raw petroleum: crude oil
● Natural gas: methane
2. Fossil-Fuel Resources
● How oil and gas forms
● Crude oil forms under limited
conditions called the “oil window”
● Crude oil resides in porous rock
called an oil reservoir (oil trap)
● Similar conditions apply to gas
2. Fossil-Fuel Resources:
Traps for Oil and Gas
2. Fossil-Fuel Resources
● Distribution of oil resources
● Middle East 2/3 of oil
● U.S. Gulf Coast and
Caribbean
● Other areas
2. Fossil-Fuel Resources:
Estimated World Oil Reserves
2. Fossil-Fuel Resources
● Oil production and consumption
● 2004-2008, 30 billion barrels/yr
● U.S. consumes three
times what it produces
● U.S. trade deficit is largely
due to oil importation
2. Fossil-Fuel Resources
● Oil production and consumption
● Hubbert’s peak shows the
time of maximum production
● U.S. peak in 1970
● Global peak very soon
2. Fossil-Fuel Resources:
U.S. Oil Production and Hubbert’s Peak
2. Fossil-Fuel Resources:
Projection of World Oil Production
2. Fossil-Fuel Resources
● Oil and the environment
● oil spills during production
● oil spills during transportation
● contribution of carbon dioxide
to the atmosphere
2. Fossil-fuel Resources
● Natural gas and the environment
● methane is a greenhouse gas
● easy transportation (pipelines
and LNG ships)
● contribution of carbon dioxide
to the atmosphere
2. Fossil-Fuel Resources
● Coal and the environment
● mining pollution problems
● burning and acid rain problem
● contribution of carbon dioxide
to the atmosphere
2. Fossil-Fuel Resources
● Types of coal (by % carbon)
● lignite (70% carbon)
● subbituminous
● bituminous
● anthracite (90% carbon)
2. Fossil-Fuel Resources:
Coal Fields of the U.S.
2. Fossil-Fuel Resources:
Typical Coal Strip Mine
West Virginia
2. Fossil-Fuel Resources
● Unconventional fossil fuels
● tar sands
● oil shales
Thought questions for this chapter
In what ways does Earth’s internal heat contribute to the
formation of fossil-fuel resources?
3. Alternative Energy Resources
● Nuclear energy
● fission of uranium-235
● releases heat
● heat makes steam
● steam drives turbines that
make electricity
3. Alternative Energy Resources
● Nuclear energy reserves
● mineable uraninite
● 240,000 quads available
3. Alternative Energy Resources
● Nuclear energy and its hazards
● environmental contamination
lasts a long time
● waste disposal problems; no
good plan in place for wastes
● security concerns
3. Alternative Energy Resources:
Planned U.S. Nuclear Waste Repository
Yucca Mountain Nuclear Waste Repository, Nevada
3. Alternative Energy Resources
● Solar energy
● electricity generation in several
ways
● risk-free and non-depletable
● technology is expensive and
inefficient
3. Alternative Energy Resources:
Solar Energy Collectors in Germany
3. Alternative Energy Resources
● Hydroelectric energy
● water and gravity
● clean and inexpensive
● 3 quad/year from this source
3. Alternative Energy Resources:
Three Gorges Dam, Yangtze River, China
3. Alternative Energy Resources
● Biofuels
● carbon neutral
● ethanol (replaces gasoline)
3. Alternative Energy Resources:
Switchgrass, a Biofuel Grown in the U.S.
3. Alternative Energy Resources
● Wind power
● uses 30-m high windmills
● requires large open space
3. Alternative Energy Resources:
Altamont, California Windmill Area
3. Alternative Energy Resources
● Geothermal
● 40 quads accessible
● disposal problems
Thought questions for this chapter
Are you an oil optimist or an oil pessimist? Explain why.
What issues related to the use of nuclear power can be
addressed by a geologist?
Contrast the risks and benefits of nuclear fission and coal
combustion as energy sources?
4. Global Change
● The risk of fossil-fuel burning
● global warming due to
greenhouse gasses
● ocean acidification
● species loss due to
biosphere changes
4. Global Change:
Global Warming / Greenhouse Gasses
● Since the industrial revolution
● methane up 150%
● carbon dioxide up 36%
● nitrous oxide up 18%
4. Global Change:
Global Warming / Greenhouse Gasses
● Anthropogenic (human) change
● global average 0.6oC increase
● rise due to greenhouse gasses
● global warming will continue into
the 21st century
4. Global Change:
Global Warming / Greenhouse Gasses
4. Global Change:
Global Warming / Greenhouse Gasses
4. Global Cchange:
Global Warming / Greenhouse Gasses
● Consequences of global warming
● changes in regional weather
● changes in the cryosphere
● sea-level rise
● species and ecosystem
migration
4. Global Change:
Predicted Surface Temperatures 20702100 as an Increase over 1960-1990
4. Global Change:
Melting of the Arctic Ice Cap by 2030
4. Global Change:
An Animal Facing Imminent Extinction
4. Global Change:
Global Warming / Greenhouse Gasses
● Potential catastrophic changes
● destabilization of glaciers
● shut-off of thermohaline
circulation in the oceans
● methane release from the
seafloor and permafrost
4. Global Change:
Ocean Acidification
● Ocean absorption of CO2
● sea water acidity is rising
● affects ability of shellfish and
coral to form their hard parts
● affects health and survival of
marine life
4. Global Change:
Loss of Biodiversity
● Effects of the Anthropocene or the
‘age of man’ (1780 to date)
● deforestation of vast areas
● mass extinction of species
● biosphere-wide impacts
4. Global Change:
The Deforestation of Haiti
Thought questions for this chapter
Do you think a geologist several thousand years from now
will consider the industrial revolution the beginning of a
new geologic epoch?
5. Earth System Engineering
and Management
● We face daunting problems.
● continued use of fossil fuels
means doubling CO2 in the
atmosphere in 50 years
● an extraordinary collaboration
of scientists, leaders, and the
public is needed
5. Earth System Engineering
and Management
● What is needed
● energy policy
● use of alternative fuels
● engineering the carbon cycle
● stabilizing carbon emissions
● sustainable development
5. Earth System Engineering
and Management
Thought questions for this chapter
What do you think will be the major sources of the world’s
energy in the year 2030? 2100?
Do you think we should act now to reduce carbon
emissions or delay until the science of climate change is
better understood?
Is the United States justified in insisting that developing
countries that now use much less fossil fuel than
developed countries agree to limit their carbon
emissions?
Thought questions for this chapter
Do you think that future scientists and engineers will be
able to intervene and prevent catastrophic changes in the
Earth system?
Key terms and concepts
Anthropogenic
Biofuel
Carbon economy
Carbon sequestration
Fossil fuel
Global change
Hubbert’s peak
Hydroelectric energy
Natural resource
Nonrenewable energy
Nuclear energy
Oil shale
Oil trap
Oil window
Quad
Key terms and concepts
Renewable resource
Reserve
Resource
Solar energy
Stabilization wedge
Sustainable development
Tar sands