1. DO NOW
Pick up notes and Review #25.

2. REVIEW
Climate zones are based on temperature and precipitation averages influenced by:
Latitude
Altitude
Ocean currents
Air Currents
What might the climate zones have looked like in Pangaea?

3. REVIEW

4. CLIMATE CHANGE
SES5. Students will investigate the interaction of insolation and Earth systems to produce weather and climate.
e. Describe the hazards associated with extreme weather events and climate change.
f. Relate changes in global climate to variation in Earth/Sun relationships and to natural and anthropogenic modification of atmospheric composition.

5. CLIMATE BASICS: EARTH’S SURFACE HEATS THE ATMOSPHERE
Molecules are warmed by radiation from Earth then retain that heat .

6. STUDYING PAST CLIMATES
Evidence
What is Measured
What is Indicated
Length of Time Measured
Picture
Ice Cores
Concentrations of gases in ice and melt water
High levels of CO2 indicate warmer climate, ice ages follow decreases in CO2
Hundreds of thousands of years
Sea Floor Sediment
Concentration of 18O in shells of microorganisms
High 18O levels indicate cool water, lower 18O levels indicate warm water

7. STUDYING PAST CLIMATES
Evidence
What is Measured
What is Indicated
Length of Time Measured
Picture
Fossils
Pollen types, leaf shapes & animal adaptations
Leaf shape indicates warm/cool climate
Millions of years
Measure the longest length of time
Tree Rings
Ring width
Thin rings indicate cool weather with less precipitation
Hundreds of thousands of years

8. CLIMATE MODELING These are computer models.
They use data collected from multiple sources to study climate.
They apply quantitative, statistical methods to develop trends and projections.
They simulate the interactions of the atmosphere, oceans, land surface, and ice
The models apply data gathered from evidence to develop trends and predictions.

9. EVIDENCE SUPPORTS CLIMATE CHANGE
Warmer atmosphere: °C since 1900.
Warmer oceans: °F since 1969.
Rise in sea levels: inches since 1900.

10. EVIDENCE SUPPORTS CLIMATE CHANGE
Acidity of surface ocean waters: + 30% since 1800.
Ice sheets are decreasing.
Increase in atmospheric CO2:  + from 280 ppm to 379 since 1800.

11. BUT RECENT WINTER WAS COLD…
You have to know the difference between
WEATHER and CLIMATE.

12. NATURAL CAUSES OF CLIMATE CHANGE
1. Continental Drift
Change impact of ocean and atmosphere currents.
2. Volcanoes
Ash reflects sunlight back to space – leads to COOLING (reduced temperatures).

13. NATURAL CAUSES OF CLIMATE CHANGE
3. Sunspot Activity
11 Year Sunspot Cycle
Low activity = colder
Example: Maunder Minimum
The Maunder Minimum is the name used for the period starting in about 1645 and continuing to about 1715 when sunspots became exceedingly rare, as noted by solar observers of the time.

14. NATURAL CAUSES OF CLIMATE CHANGE: MILANKOVITCH CYCLES
Milankovitch Cycles are cycles of Climate Change:
100,000 year variations.
Smaller variations for 20,000 to 40,000 years.

15. NATURAL CAUSES OF CLIMATE CHANGE: MILANKOVITCH CYCLES
Orbital changes produce climate shifts
Orbital eccentricity (shape of the orbit)
Earth’s tilt – varies between 22.2° and 24.5°
Axis precession – wobble variations from spin (like a spinning top wobbles)
NOT ROTATION!

16. ANTHROPOGENIC CAUSES OF CLIMATE CHANGE
Anthropogenic means human caused.
Burning fossil fuels:
Transportation and Electricity Power Plants
Releases CO2 and other greenhouse gases into atmosphere
CO2 greenhouse gas – increases temperature

17. ANTHROPOGENIC CAUSES OF CLIMATE CHANGE
Industry:
CFCs
Nitrous Oxides
Agriculture:
Fossil fuels burned to produce and transport crops.
Land use changes alter natural cycle.

18. GREENHOUSE GASES TRAP HEAT
A gas in an atmosphere that absorbs and emits infrared radiation.
Absorbs energy.
Allows less heat to escape back to space.
Traps energy in the lower atmosphere.
Increases in CO2 and CH4 are linked most closely to Global Warming and Effects.

19. GREENHOUSE GASES TRAP HEAT
Greenhouse Gases: Some natural, some pollutants
Carbon Dioxide – CO2
Methane – CH4
Water vapor – H2O
Nitrous Oxide - NOx
Ozone (Tropospheric) – O3
CFCs (Chlorofluorocarbon)

21. CLIMATE AND CARBON DIOXIDE (CO2)
Increased CO2 in atmosphere.
Increased average temperatures.
BOTH rising to historic highs.

22. EFFECTS OF CLIMATE CHANGE
Sea ice melting
Sea level rising
Changes in ocean currents
Biodiversity changes
Changes in weather patterns
Ocean acidification

23. SEA ICE MELTING

24. SEA LEVEL RISING

25. CHANGES IN OCEAN CURRENTS
Areas heated by warm ocean currents could become colder if ice cuts off currents – heat will be transferred elsewhere.

26. If the Earth warms, the climate zones and thus the biomes will change.
BIODIVERSITY CHANGES
If the Earth warms, the climate zones and thus the biomes will change.

27. CHANGES IN WEATHER PATTERNS
Changes in evapotranspiration patterns result in more droughts.
Environments becoming more arid subject to greater wind erosion.

28. OCEAN ACIDIFICATION
Carbon Dioxide in atmosphere is absorbed by ocean water.
Chemical reactions take place producing carbonic acid.
Ocean acidity up 30% since 1850.
Damages corals and other life forms.

29. CARBON CYCLE: OCEANS STORE CARBON
The carbon cycle has carbon sources and carbon sinks.
Water that absorbs CO2 forms carbonic acid through a chemical reaction.
pH decreases (more acidic) as CO2 absorbed.

30. REVIEW
What percentage of climate scientists agree that climate-warming trends over the past century are very likely due to human activities:
A. 33%
B. 50%
C. 72%
D. 97%

31. TO DO
Work on Review #25
Work on missing labs.