1. THE HUMAN IMPACT ON EARTH’S ENVIRONMENT
Grotzinger • Jordan
Understanding Earth
Seventh Edition
Chapter 23:
THE HUMAN IMPACT ON EARTH’S ENVIRONMENT
© 2014 by W. H. Freeman and Company

2. The Human Impact on Earth’s Environment
Chapter 23
The Human Impact on Earth’s Environment

3. 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.

4. Lecture Outline Civilization as a global geosystem
2. Fossil-fuel resources
3. Alternative energy resources
4. Global change

5. Lecture Outline
5. Earth system engineering and management

6. 1. Civilization as a Global Geosystem
Civilization exists at the thin interface among the climate, plate tectonic, and geodynamic systems.
Human civilization has profoundly altered the planet, especially in the last 200 years.

7. Civilization as a Global Geosystem: Human Population Growth
10,000 years ago – 100 million people
5,000 years ago – 200 million people
700 years ago – 400 million people
By 1800 AD – 1 billion people
By 1974 – 4 billion people
By 2012 – 7 billion people
(World’s population doubles now in 47 years.)

8. Civilization as a Global Geosystem: Human Population Growth
Scenario A: continued growth as now; B: late 21st-century level-off; C: decline after 2070

9. 1. Civilization as a Global Geosystem
Humans now alter the global environment on a scale that is staggering compared to natural processes.

10. ● Example of human changes ● dams and reservoirs now trap
1. Civilization as a Global Geosystem
● Example of human changes
● dams and reservoirs now trap
30% of all river sediments
● humans move more soil and rock
than all natural processes
● one third of forests cleared
● coolants have damaged the critical ozone layer
● carbon dioxide levels up by ~50%

11. ● Natural energy resources ● Renewable energy resources
1. Civilization as a Global Geosystem
● Natural energy resources
● Renewable energy resources
● biomass (wood burning)
● Nonrenewable energy resources
● fossil fuels (oil, gas, coal)

12. 1. Civilization as a Global Geosystem

13. ● After 1850: the rise of the U.S. fossil-fuel economy.
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.

14. 1. Civilization as a Global Geosystem*
* Note – a quad is = to 1015 Btus.

15. ● Global energy consumption ● quad = 1015 Btus
1. Civilization as a Global Geosystem
● Global energy consumption
● quad = 1015 Btus
● U.S. in 2012 = 95 quads
● global in 2012 = 530 quads
● 2012 consumption in U.S. is ~ 4 times per person versus the world

16. Civilization as a Global Geosystem:
U.S. Energy Consumption

17. Civilization as a Global Geosystem: Projected Energy Consumption*
* Note – OECD includes North America, western Europe, and Australia.

18. ● Global carbon flux from energy production
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

19. ● Fossil-fuel resources and reserves ● Resources – have been
discovered
● Reserves – remain in Earth

20. 2. Fossil-Fuel Resources: Remaining Nonrenewable Fossil Fuel

21. ● May move to reservoirs ● Raw petroleum: crude oil
2. Fossil-Fuel Resources
● How oil and gas forms
● Formed in source beds
● May move to reservoirs
● Raw petroleum: crude oil
● Natural gas: methane

22. ● Crude oil forms under limited conditions called the “oil window.”
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.

23. 2. Fossil-Fuel Resources:
Traps for Oil and Gas

28. ● Distribution of oil resources ● Middle East ● U.S. Gulf Coast and
2. Fossil-Fuel Resources
● Distribution of oil resources
● Middle East
● U.S. Gulf Coast and
Caribbean
● Other areas

29. 2. Fossil-Fuel Resources: Estimated World Oil Reserves

30. ● Oil production and consumption ● In 2012, 35 billion barrels/yr
2. Fossil-Fuel Resources
● Oil production and consumption
● In 2012, 35 billion barrels/yr
● U.S. consumes ~2 times
what it produces
● U.S. trade deficit is heavily due to oil importation

31. ● Oil production and consumption ● Hubbert’s peak shows the
2. Fossil-Fuel Resources
● Oil production and consumption
● Hubbert’s peak shows the
time of maximum production
● U.S. peak in 1970
● Departure from trend
started in 2008

32. 2. Fossil-Fuel Resources: U.S. Oil Production and Hubbert’s Peak

33. ● Oil and the environment ● oil spills during production
2. Fossil-Fuel Resources
● Oil and the environment
● oil spills during production
● oil spills during transportation
● contribution of carbon dioxide
to the atmosphere

34. 2. Fossil-Fuel Resources
Oil spill during production:
The Deepwater Horizon disaster (2010)

35. ● Natural gas production ● new technology – “fracking”
2. Fossil-Fuel Resources
● Natural gas production
● new technology – “fracking”
● gas from shales is the new
frontier for exploration

36. 2. Fossil-Fuel Resources
Fracking:
Producing gas
from shale
formations

37. 2. Fossil-Fuel Resources
Fracking:
How shale gas
production is
changing the
outlook of gas
production in
the U.S.

38. ● Natural gas and the environment ● Natural gas burns more
2. Fossil-Fuel Resources
● Natural gas and the environment
● Natural gas burns more
cleanly than coal.
● Natural gas has higher carbon
intensity than coal.
● Methane is a greenhouse gas,
and burning gas emits CO2.

39. ● Types of coal (by % carbon) ● lignite (70% carbon) ● sub-bituminous
2. Fossil-Fuel Resources
● Types of coal (by % carbon)
● lignite (70% carbon)
● sub-bituminous
● bituminous
● anthracite (90% carbon)

40. ● Coal and the environment ● mining pollution problems
2. Fossil-Fuel Resources
● Coal and the environment
● mining pollution problems
● burning and acid rain problem
● contribution of carbon dioxide
to the atmosphere

41. 2. Fossil-Fuel Resources:
Coal Fields of the U.S.

42. 2. Fossil-Fuel Resources: Typical Coal Strip Mine
West Virginia

43. ● Unconventional fossil fuels ● heavy oil ● tar sands
2. Fossil-Fuel Resources
● Unconventional fossil fuels
● heavy oil
● tar sands
● natural bitumen
● oil shales

44. Thought questions for this chapter
In what ways does Earth’s internal heat contribute to the formation of fossil-fuel resources?

45. ● steam drives turbines that make electricity
3. Alternative Energy Resources
● Nuclear energy
● fission of uranium-235
● releases heat
● heat makes steam
● steam drives turbines that
make electricity

46. ● Nuclear energy reserves ● mineable ore − uraninite
3. Alternative Energy Resources
● Nuclear energy reserves
● mineable ore − uraninite
● 240,000 quads available

47. ● Nuclear energy and its hazards ● environmental contamination
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

48. 3. Alternative Energy Resources: Planned U.S. Nuclear Waste Repository
Yucca Mountain Nuclear Waste Repository, Nevada

49. ● Biofuels ● carbon neutral ● ethanol may replace gasoline
3. Alternative Energy Resources
● Biofuels
● carbon neutral
● ethanol may replace
gasoline

50. 3. Alternative Energy Resources:
Switchgrass, a Biofuel Grown in the U.S.

51. ● electricity generation ● risk-free and nondepletable
3. Alternative Energy Resources
● Solar energy
● electricity generation
● risk-free and nondepletable
● technology is expensive and
inefficient
● ~0.2 quad/year in the United
States

52. 3. Alternative Energy Resources: Solar Energy Collectors in California
Mojave Desert

53. ● Hydroelectric energy ● water, plus gravity ● clean and inexpensive
3. Alternative Energy Resources
● Hydroelectric energy
● water, plus gravity
● clean and inexpensive
● ~2.7 quad/year in the
United States

54. 3. Alternative Energy Resources:
Three Gorges Dam, Yangtze River, China

55. ● Wind power ● requires very tall windmills ● requires large open
3. Alternative Energy Resources
● Wind power
● requires very tall
windmills
● requires large open
spaces with constant
winds

56. 3. Alternative Energy Resources: Alta Wind Energy Center, California
Kern County, California

57. ● Geothermal ● ~0.3 quads/year ● disposal problems
3. Alternative Energy Resources
● Geothermal
● ~0.3 quads/year
● disposal problems

58. Thought questions for this chapter
Are you an oil optimist or an oil pessimist? Explain why.
What issues related to the use of nuclear energy can be addressed by geologists?
Contrast the risks and benefits of nuclear fission and coal combustion as energy sources?

59. ● The risk of fossil-fuel burning ● global warming due to
4. Global Change
● The risk of fossil-fuel burning
● global warming due to
greenhouse gasses
● ocean acidification
● species loss due to
biosphere changes

60. Global Warming / Greenhouse Gasses
4. Global Change:
Global Warming / Greenhouse Gasses
● Since the industrial revolution
● methane up 150%
● carbon dioxide up 48%
● nitrous oxide up 20%

61. Global Warming / Greenhouse Gasses
4. Global Change:
Global Warming / Greenhouse Gasses
● Anthropogenic (human) change
● global average 0.9oC increase
● rise due to greenhouse gasses
● global warming will continue into
the twenty-first century
● significant changes will occur

62. Global Warming / Greenhouse Gasses
4. Global Change:
Global Warming / Greenhouse Gasses

63. Predictions of the Future − Average Surface Temperature of Earth
4. Global Change:
Predictions of the Future −
Average Surface Temperature of Earth
Scenario A: continued growth as now; B: late 21st-century level-off; C: decline after 2050

64. Consequences of Climate Change
4. Global Change:
Consequences of Climate Change
● Consequences of global warming
● changes in regional weather
● changes in the cryosphere
● sea-level rise
● species and ecosystem
migration

65. Consequences of Climate Change
4. Global Change:
Consequences of Climate Change
Predicted
Average
Surface
Temperatures
Scenario A: continued growth as now; B: late 21st-century level-off; C: decline after 2050

66. Consequences of Climate Change
4. Global Change:
Consequences of Climate Change
An Animal Facing Imminent Extinction

67. Potential
Effects of
Climate
Change:
Reviewing
Ecosystems

68. Consequences of Climate Change
4. Global Change:
Consequences of Climate Change
● Potential catastrophic changes
● destabilization of glaciers
● shut-off of thermohaline
circulation in the oceans
● methane release from the
seafloor and permafrost

69. ● Ocean absorption of CO2 ● sea water acidity is rising
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

70. ● Effects of the Anthropocene or the “age of man” (1780 to date)
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

71. The Deforestation of Haiti
4. Global Change:
The Deforestation of Haiti

72. 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?

73. 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

74. 5. Earth System Engineering and Management
● What is needed
● energy policy
● use of alternative fuels
● engineering the carbon cycle
● stabilizing carbon emissions
● sustainable development

75. 5. Earth System Engineering and Management

76. 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?

77. Thought questions for this chapter
Do you think that future scientists and engineers will be able to intervene and prevent catastrophic changes in the climate system?

78. Key terms and concepts Biofuel Carbon economy Carbon intensity
Anthropogenic
Biofuel
Carbon economy
Carbon intensity
Carbon sequestration
Fossil fuel
Global change
Hydraulic fracturing (fracking)
Hydroelectric energy
Natural resource
Nonrenewable resource
Nuclear energy
Oil trap
Oil window
Quad

79. Key terms and concepts Reserve Resource Solar energy
Renewable resource
Reserve
Resource
Solar energy
Stabilization wedge
Sustainable development