1. Final Exam Review Sessions:
Notes Tuesday 04/29
Fire essays due today
Next Tuesday 05/06: Take last quiz (Cultural Chronology), Extra Credit & Fire Essays returned
In-class reviews
Thurs 05/01 (part 3)
Tues 05/06 (comprehensive question)
Final Exam Review Sessions:
Friday 05/09
…or…
Monday 05/12

2. Global Change
Includes: ozone hole, acid rain, pollution, habitat destruction & extinction, exotic species, climate change
We’ll focus on atmospheric CO2 increase
Some carbon-temperature basics
Some SW specific ramifications
Vegetation migrations?
What is known vs. what is speculation.

3. Carbon Cycle
Units: Pg (Petagram, 1015 g)
Major storage:
Minor storage:
Trivial storage:
Fluxes to atmo:

4. Anthropogenic CO2 Fossil fuels: - Land use change: -
Anthropogenic CO2
Fossil fuels: -
Land use change: -

5. 380 8 Atmospheric CO2 Long-term increase Seasonal swings Why?
How much is 380 ppm??
380 8

7. Carbon Equation of Life

8. Direct CO2 Fertilization
If: plants need CO2, and
Given: more CO2 is available, then
Plants should grow better
How can we tell?

9. Elevated CO2 in Arid Lands
Pour CO2 over small plots
FACE: Free-Air CO2 Enrichment

10. CO2 Effects Deserts
Depends on moisture: -

12. -

13. Global Warming & Precipitation Recap:
Difficult to predict: -
Warmer atmosphere: -
Might expect more vigorous circulation:

14. Greenhouse Warming: A Good Thing-

15. Radiation Comes in WavelengthsUV IR
Radiation Comes in Wavelengths
Visible: -
Sun’s radiation: -
Earth’s radiation: -

16. Greenhouse Gas Absorption
Water vapor –
CO2
Trace gases -

17. Instrumental record shows warming
research/2007/perspectives.html
Global Warming?
Instrumental record shows warming
Ocean or land
Now: warmest years ever: 2.2°F above avg.
Skeptical?

18. 2° F (1° C) Increase?

19. Still Skeptical?
Urban Heat Island Effect
Buildings, pavement absorb sun, emit heat

20. Warm Cities
Is this the cause of modern warming?

21. Still Skeptical??
Natural variability is causing temp rise!

23. Paleo Temperatures? Worldwide temperature reconstruction
Tree rings, ice, pollen, corals

25. Intergovernmental Panel on Climate Change (IPCC) Global Temperature Change
4th report (2007): up to 4°C warmer by 2100…
= business as usual
=moderate fossil fuel use, + shift to renewables
= total switch to nuclear

26. For “business as usual” scenario….
an “average” of 3 degrees C….

27. How might ecosystems respond?
Therefore, elevational displacement:
Up to 600 m (~1500 ft.)
Does this ring a bell from the past?

28. Could lose alpine in north, subalpine in south

29. Douglas-fir:
CA White Oak:
Forest migrations
Out with old (Douglas-fir, ponderosa pine), in with new (Cal. White oak)

30. Saguaro -

31. So What if We Lose Ecosystems?
Ecosystem services -

32. Global Change
It is warming up: -
Environment appears to be changing -
SW ecosystems likely to change
What to do?

33. One More thing …
Globally, glaciers in retreat
Sea level rising 1.5mm / yr

34. Will the other shoe drop?
Could it actually become cooler while warming? -
Past: -
See optional reading…