1. The Human Impact on Earth’s Environment
Lecture 34
The Human Impact on Earth’s Environment

2. 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.

3. 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.

4. 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.)

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

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

7. ● 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%

8. ● 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)

9. ● 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.

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

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

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

13. ● 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

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

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

16. ● 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

17. ● 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.

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

23. ● 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

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

25. ● 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

26. ● 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

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

28. ● 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

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

30. ● 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

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

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

34. ● 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.

35. ● 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

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

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