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

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.

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

Anthropogenic CO2 Fossil fuels: - Land use change: - http://www.whrc.org/carbon/index.htm Anthropogenic CO2 Fossil fuels: - Land use change: -

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

Carbon Equation of Life

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

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

CO2 Effects Deserts Depends on moisture: -

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

Greenhouse Warming: A Good Thing -

Radiation Comes in Wavelengths UV IR Radiation Comes in Wavelengths Visible: - Sun’s radiation: - Earth’s radiation: -

Greenhouse Gas Absorption Water vapor – CO2 Trace gases -

Instrumental record shows warming http://lwf.ncdc.noaa.gov/oa/climate/ research/2007/perspectives.html Global Warming? Instrumental record shows warming Ocean or land Now: warmest years ever: 2.2°F above avg. Skeptical?

2° F (1° C) Increase?

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

Warm Cities Is this the cause of modern warming?

Still Skeptical?? Natural variability is causing temp rise!

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

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

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

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

Could lose alpine in north, subalpine in south

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

Saguaro -

So What if We Lose Ecosystems? Ecosystem services -

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

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

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