1. Energy & Its Impact on Global Society
Jerome K. Williams, Ph.D.
Saint Leo University
Dept. Mathematics & Sciences

2. Chapter 9: Global Warming & Thermal Pollution
Overview
Greenhouse Effect & Global Warming
Possible Impacts: Global Warming
Actions: What can be Done?
Thermal Pollution

3. Overview

4. Overview
Evidence suggests that burning fossil fuels can raise Earth’s temperature and potentially change the climate of the entire planet.
Global Warming (Greenhouse Effect)

5. Greenhouse Effect & Global Warming
Greenhouse effect caused by gases in atmosphere that absorb infrared energy from the Earth that would otherwise escape into space.
Earth’s temperature is a balance between the energy coming in from Sun and energy that is radiated from Earth back into space.

9. Greenhouse Effect & Global Warming
Gases that are responsible for this effect:
Carbon dioxide (CO2)
Methane (CH4)
Nitrogen oxides (NO NO2)
Chlorofluorocarbons (CFCs)

10. Table 9.1. Greenhouse Gases 2010
Source: Intergovernmental Panel on Climate Change
Table 9.1. Greenhouse Gases 2010
Gas
Sources
US Emissions (MT/yr)
GWP
Atmospheric Lifetime (years)
2010 Concentration (ppM)
CO2
Fossil Fuels, deforestation
5500 1
100
392
Methane
Rice fields, cattle, landfills
600 21 12
1.8
Nitrogen oxides
Fertilizers, deforestation 16
310
120
0.31
CFCs
Aerosol sprays, refrigerants
,000
70-100
0.003 (Cl atoms)

11. Greenhouse Effect & Global Warming
GWP = Global Warming Potential (ability of greenhouse gas to trap heat).
CO2 levels are a Global Problem that can have devastating environmental consequences if not addressed soon.

12. Global Warming Consequences

13. Global Warming Consequences

14. Possible Impacts: Global Warming
Determining the impact of global warming in the 21st century is very difficult
Climate models about complex physical processes are based on assumptions and therefore contain many uncertainties

15. Possible Impacts: Global Warming
Climate Sensitivity - defined as temperature rise that will occur when CO2 concentrations double from pre-industrial levels
Many scientists think that doubling will occur by middle of this century (assumes a 1-2% annual increase in CO2 levels is maintained)

17. Possible Impacts: Global Warming
Most scientists (but not all) agree that increasing CO2 levels will affect the planet’s climate, the key questions are as follows:
How much of a change will be observed?
How fast will global temperatures rise?

18. Possible Impacts: Global Warming
A key element in predicting the rise in global temperatures is to understand carbon cycle

20. Possible Impacts: Global Warming
Much of uncertainty with predicting warming trends depends on understanding of sizes of various feedbacks that may occur in response to climate changes

21. Possible Impacts: Global Warming
Effects of global warming will not be felt equally around the world.
Poorer nations more susceptible to effects of global warming; widespread poverty across Africa makes it particularly vulnerable

22. Actions: What can be Done?
What can be done to prevent greenhouse gas concentrations from rising to unacceptable levels?
Energy Policy coupled with Political Leadership

23. Actions: What can be Done?
Energy Policy:
Energy conservation
Economic incentives
Renewable energy technologies
Employ more natural gas & nuclear power
US: 20 metric tons CO2 /yr (6X greater than developing world)

24. Actions: What can be Done?
Political Leadership (Legislative Action)
“Cap and Trade” Policy
Carbon Tax
Carbon Sequestration

25. Actions: What can be Done?
Will Everyone Play in the same Sand Box?
International strategies must be developed and followed by everyone for this to work
Built-in-bias against solving long-term problems
Very expensive to fix problem; affects bottom line
Controversial (skeptics still out there)

26. Actions: What can be Done?
Recent History: Do Nations Play well together?
1992 Earth Summit (Rio de Janeiro)
Countries must exercise “responsible stewardship”
Compliance was voluntary
1997 Kyoto Protocol on Global Climate Change

27. Thermal Pollution
Thermal pollution is defined as addition of unwanted heat to environment, particularly natural waters
Greatest source of heated water is from power-generating stations

28. Thermal Pollution Ecological Effects of Thermal Pollution
Decreased ability of water to hold oxygen
Increased rates of chemical reactions
Changes in food chain of ecosystem
Long-term damage (even death) to natural bodies of water

29. Thermal Pollution
Current US laws dictate that one can not just “dump” waste heat directly into aquatic environments
Cooling Towers
Cooling Ponds

30. Thermal Pollution Using Waste Heat for other Benefits include
Hot water for industrial use
Aquaculture (increased fish growth)
Greenhouse heating
Desalination of sea water
Increased crop growth and frost protection

31. Problems
1, 2, 3