1. Chapter 19 Global Change 2 hour video from PBS called “Heat”
- 1 hour video “Dimming of the Sun”
Chapter 19
Global Change

2. Global Change
Global change- any chemical, biological or physical property change of the planet.
Global climate change- changes in the climate of the Earth.
Global warming- the warming of the oceans, land masses and atmosphere of the Earth.

3. The Sun-Earth Heating System
The Greenhouse Effect
Incoming solar energy = 100%
- Radiation is absorbed by the clouds and the surface of Earth thus becoming warmer.
I/3 of all solar energy is reflected.
Most of the infrared radiation from Earth is absorbed by greenhouse gases in the atmosphere.
- The rest is emitted back into space.
- Known as the greenhouse effect.

5. Greenhouse Gases Water vapor Carbon dioxide Methane Nitrous oxide
Absorbs and releases energy
Carbon dioxide
Methane
Nitrous oxide
Ozone
CFCs
N2 and O2 do NOT MAKE THE LIST
W/o GHG, Average earth temp would be 0F….practically unlivable

6. How much infrared the molecule can absorb
How long does it persist in the atmosphere
Greenhouse warming potential—ratio of how much a molecule of a compound can contribute to global warming over 100 years compared to 1 molecule of CO2

7. 4 Natural Greenhouse Gases
1. Volcanic eruptions
CO2—long term effects
Particulate Matter — (ash) shorter term
Ash reflects incoming solar radiation back to space, causes Earth’s temperature to decrease.
Sun Spots – solar energy
Changes in Earth’s orbit
Changes in axis tilt and wobble

8. 4 Natural Greenhouse Gases
2. Methane – is created when there is not enough oxygen available to produce carbon dioxide during decomposition.
Occurs at the bottom of wetlands – largest natural source of methane (anaerobic decomposition)
Organism digestion, gut of a termite, no oxygen is present methane given off. Second largest source.
Cows go under anthropogenic---we are specifically raising them in these high numbers

9. 4 Natural Greenhouse Gases
3. Nitrous oxide
Produced during denitrification
NO3-  N2O
Occurs in a low oxygen environment such as soils at the bottom of wetlands, lakes, and oceans.

10. 4 Natural Greenhouse Gases
4. Water vapor
Most abundant
Greatest contributor
Sun Spots – solar energy
Changes in Earth’s orbit
Changes in axis tilt and wobble

11. 5 Anthropogenic Sources of Greenhouse Gases

12. 5 Anthropogenic Sources of Greenhouse Gases
1. Burning of fossil fuels
Trapped reserves of CO2 plants don’t take in as much as we are contributing during burning.
Coal v. Petroleum v. Natural gas
Particulate Matter
“Black soot”

13. 5 Anthropogenic Sources of Greenhouse Gases
2. Agricultural practices
Anaerobic conditions (CH4 and N2O)
Irrigation and flooding for cultivating crops create low oxygen environments for bacteria.
Fertilizers
Excess Nitrates are added denitrification = N2O
Livestock
Digestion – sheep and cows rely on gut bacteria to break down cellulose which produces a lot of CH4
Manure lagoons – not aerated, decompose and release CH4

14. 5 Anthropogenic Sources of Greenhouse Gases
3. Deforestation…without replacement
Plants remove CO2
Slash-and-burn method (shifting agriculture)
releases CO2, CH4, and N2O

15. 5 Anthropogenic Sources of Greenhouse Gases
4. Landfills
Anaerobic methane generation from low oxygen due to poor aeration.

16. 5 Anthropogenic Sources of Greenhouse Gases
5. Industrial production
CFCs replaced by HCFCs

18. Increasing CO2 Concentrations
David Keeling began measuring CO 2 in 1958.
Svante Arrhenius
A Swedish scientist first to claim in 1896 that fossil fuel combustion may eventually result in enhanced global warming.
Charles Keeling
Produce concentration curves for atmospheric CO2 starting in 1958
280ppm = preindustrial levels
392ppm levels in 2011 add 2ppm yearly
350ppm considered safe for life as we know it
450ppm or 20C change = serious weather change

19. Emissions from the Developed and Developing World

20. Temperatures and Greenhouse Gas Concentrations in Past 400,000 Years
Indirect measurements—lack of records
Changes in species compositions
Foraminifera
Chemical analyses of ice

21. Historic CO2 Concentrations

22. Historic CO2 Concentrations

23. Putting It Together
- We know that an increase in CO2 in the atmosphere causes a greater capacity for warming through the greenhouse effect. - When the Earth experiences higher temperatures, the oceans warm and cannot contain as much CO2 gas and, as a result, they release CO2 into the atmosphere.

24. Evidence of Global Climate Change
1. Global sea level rose about 17 centimeters (6.7 inches) in the last century. The rate in the last decade, however, is nearly double that of the last century.
2. Average Arctic temperatures increased at almost twice the global average rate in the past 100 years. Shrinking glaciers and ice caps.
Most of this warming has occurred since the 1970s, with the 20 warmest years having occurred since 1981 and with all 10 of the warmest years occurring in the past 12 years.
Seasonal events starting earlier and ending later
The top 700 meters (about 2,300 feet) of ocean showing warming of degrees Fahrenheit since 1969
The number of record high temperature events in the United States has been increasing, while the number of record low temperature events has been decreasing, since The U.S. has also witnessed increasing numbers of intense rainfall events.

25. Feedbacks MANY INTERCONNECTED SUBSYSTEMS
Increase in CO2 in the atmosphere causes a greater capacity for warming through the greenhouse effect.
When the Earth experiences higher temperatures, the oceans warm and cannot contain as much CO2 gas and, as a result, they release CO2 into the atmosphere.

26. Feedbacks POSITIVE NEGATIVE High C in soil High temperatures
 decomposition
 CO2 in atmosphere
Tundra warms
Anaerobic decomposition
CH4
NEGATIVE
High CO2
 plant growth
Removes CO2
MANY INTERCONNECTED SUBSYSTEMS
Increase in CO2 in the atmosphere causes a greater capacity for warming through the greenhouse effect.
When the Earth experiences higher temperatures, the oceans warm and cannot contain as much CO2 gas and, as a result, they release CO2 into the atmosphere.

27. Consequences to the Environment From Global Warming
1. Melting of polar ice caps, Greenland and Antarctica
2. Melting of many glaciers around the world
3. Melting of permafrost
4. Rising of sea levels due to the melting of glaciers and ice sheets and as water warms it expands
5. Heat waves more frequent
6. Cold spells lessening
7. Change in precipitation patterns
8. Increase in storm intensity
9. Shift in ocean currents

28. The Melting Polar Ice Cap
9” rise since 1870
By end of 21st centure, could be 7-23” higher
Almost 1/5 of US lives in coastal areas…
North Pole is currently 39% smaller than it was in 1979

29. Rising Sea Levels Thermal expansion
9” rise since 1870
By end of 21st centure, could be 7-23” higher
Almost 1/5 of US lives in coastal areas…
Thermal expansion
Additions of water from melting ice

30. Consequences to Living Organisms
Wild plants and animals can be affected. The growing season for plants has changed and animals have the potential to be harmed if they can’t move to better climates.
Humans may have to relocate, some diseases like those carried by mosquitoes could increase and there could be economic consequences.

31. Consequences to Living Organisms

32. The Controversy of Climate Change
The fundamental basis of climate change- that greenhouse gas concentrations are increasing and that this will lead to global warming is not in dispute among the vast majority of scientists.
What is unclear is how much world temperatures will increase for a given change in greenhouse gases, because that depends on the different feedback loops.

33. The Kyoto Protocol
1997, Japan--discuss how best to control emissions contributing to global warming.
Green house gas emissions from all industrialized countries will be reduced to 5.2% below their 1990 levels by 2012.
Developing nations did not have emission limits imposed by the protocol.
We suck
Here’s what happened
Bill Clinton knew that the Senate would never agree because
No restrictions on developing nations
Could harm US economy
Clinton told Gore to sign it, but never sent to Senate
In 2001, Kyoto Protocol was modified to get more developed nations on board
GW Bush said that there was too much “uncertainty” about global warming
Unfair to our economy…too costly to do
ALL countries should have limits
Still not involved
2007, EPA decided to include GHG to Clean Air Act
2010, 190 countries involved
We are the ONLY developing nation not to…WTF
2009, Copenhagen meeting
No one wanted to agree to anything… “climate change is bad, mmkay”