1. HUMAN IMPACT ON CLIMATE CHANGE Chapter 8

2. PALEOCLIMATOLOGY Evidence of Past Climate Change
We will focus on Tree rings & Ice cores
There are actually more, for a comprehensive list see:
When these independent lines of evidence are combined, a more complete picture of past climate change can be formed.
Only by understanding the natural cycles of past climate change before humans became such a large presence on the planet, can we determine if humans have affected or are affecting the climate.

3. Quick Lab: Climate & Tree Growth (Page 297 )
Arrange the tree cores so that you have a continuous record from 1959 to 2008.
ANSWER:
Has climate changed during this time period?
What is the evidence?
HW: Follow procedure & Answer questions #5 - 8

4. Page 297

5. Tree Ring Data Most tree ring data shows several decades
Some trees on the Bruce Peninsula are 400 years old
Oldest known tree is about 8000 years old
Three major climatic factors affect tree growth
Sunlight, water and carbon dioxide
Indirect (Proxy) Evidence of Climate Change
Patterns from Ring Data
Thick ring = more growth
More photosynthesis due to higher CO2 in air, which leads to a higher temperature
More precipitation
More sunlight
Thin ring = slower growth
Less photosynthesis due to lower CO2 in air, which leads to lower temperature
Less precipitation
Less sunlight

6. Ice Core Data
Trapped air bubbles contains samples of ancient atmosphere
Direct evidence of Climate Change
These gases that can be analyzed
Long-term patterns (400, 000 years)

7. What do these graphs show?

8. Correlation vs. Cause & Effect
Analyzing graphs is a useful skill, but you must be careful
The ice core data shows correlation between atmospheric CO2 and temperature, it does not show cause & effect

9. Direct Temperature Measurements Show That The Earth is Warming
Thermometers
Satellite Remote Sensing
Watch video at:
These maps show temperatures across the world in the 1880s (left) and the 1980s (right), as compared to average temperatures from 1951 to Earth's average surface temperature has increased almost 1.5°C during the 20th century. Two-thirds of the warming has occurred since 1975, at a rate of roughly 0.3°C-0.4°C per decade. Source: NASA

10. Because of Greenhouse Gases
Naturally occurring
Carbon dioxide
Methane
Nitrous oxide (dinitrogen monoxide)
Water
Anthropogenic (man-made)
hydrofluorocarbons (HFCs) and chlorofluorocarbons (CFCs) [These are the same gases that caused the hole in the ozone layer]
Human activity produces more carbon dioxide, methane and nitrous oxide than occurs naturally (page 300)

11. Greenhouse Gases Graph
FROM:

12. Anthropogenic Greenhouse Effect
FROM:

13. Carbon Sources & Sinks Sources Sinks Burning fossil fuels Respiration
Volcanic eruptions
Sinks
Ocean (carbon dioxide dissolves better in water than air)
Phytoplankton (algae) in ocean perform most photosynthesis on earth
Forests perform photosynthesis

14. Home Fun! Page 302 # 1- 5 Page 319 #1, 4 - 7, 9 – 14
Go to Dr. Douglas Fir’s Lab and complete the tree ring study at:

15. From: http://www.ipcc.ch/publications_and_data/ar4/syr/en/mainssyr-introduction.html

16. Effects of Global Warming
Atmosphere
Heat Waves
Drought
Wildfires
Storms
Floods
Hydrosphere
Melting Ice
Ocean Warming
Ocean Currents
Ocean Acidification

17. Effects of Global Warming
Biosphere
Range Shifts
Threatened Species
Affects ALL living organisms, some more than others
Some organisms may benefit
eg. Poison Ivy & jellyfish

18. Home Fun!
Page 319 #4, 6, 7, , 16, 17
Page 363 #7 & 24
Check out changes in sea level & sea ice in the recent past at:

19. Feedback Loops Positive Negative Effect becomes amplified
Global warming causes ice to melt which lowers albedo which causes less reflection of sun’s energy, which causes more warming which causes more melting (runaway feedback loop, a.k.a. “vicious cycle”)
Negative
Effect is inhibited
Example: Thermostat on an air conditioner (when the set temperature is reached, the cooling unit shuts off)

20. Modelling Climate Change (page 339)

21. Home Fun
Page 323 #3
Page 330 #3, 6, 10, 11,
Explore pop-up beneath the global temperature maps.

22. What to do about Global Warming?
MITIGATION
Change philosophy & behaviour to reduce carbon emissions by:
Using less fossil fuels
Carpooling, cycling, walking, working from home
Using alternative methods of producing electricity
Wind, solar, tidal, fuel cells
Legislation
Carbon Tax, carbon trading
Localized economies
Less travel, more secure
ADAPTATION
Manage/reduce the impacts of events such as floods, storms, droughts
Technology

23. Technology Carbon Sequestration Geoengineering (a.k.a. planet hacking)
Cogeneration
Geoengineering (a.k.a. planet hacking)
Watch this 3 minute interview and write a one paragraph response:
5 ways to save the planet video

24. Carbon Sequestration

25. Home Fun
Page 347 #3, 11, 12
Page 360 # 1- 5, 8, 11, 15