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Wasting class time?

Wasting class time?. Please get out your objectives #3-9 for a stamp. Add new learnings as you compare your work with your neighbor’s. Climate – on a geologic scale. First, try this:. Take the average of the following numbers: 100, 0

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Wasting class time?

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  1. Wasting class time? • Please get out your objectives #3-9 for a stamp. • Add new learnings as you compare your work with your neighbor’s.

  2. Climate – on a geologic scale

  3. First, try this: • Take the average of the following numbers: 100, 0 • Take the average of 100,100,100,100,100,100,100,100,100,& 0 • (that’s 9 sets of 100)

  4. How does having more data affect an average? 2013 global average temperature 58.3 oF

  5. Observations?

  6. Three important inferences • Climate change is natural • 100,000 year cycles between glacial maximum (ice age) and interglacial periods (maximum warmth) • A change in -3oC (about -5oF) can create an ice age • *Historically, the RATE has been slow enough that species could evolve to keep up with the changes.

  7. Earth’s orbit around the sun Milankovitch cycles create the 100,000 yr pattern • Obliquity (Axial tilt) • Eccentricity (orbit eliptical or circular) • Precession (wobble on axis) • Combination of these creates 100,000 year cycle of warming and cooling

  8. CO2 levels • Where did CO2 come from thousands of years ago? • Response of ocean to increased radiation: warm ocean releases CO2 • CO2 at beginning of Industrial revolution: 280 ppm • Current CO2 levels: 396ppm

  9. Where did this data come from?

  10. Studying geologic climate • Historic records exist 150 years • Inferred/Implied records • Fossil records • Tree rings – relative amounts of oxygen isotopes (proxy methods) • Ice cores - paleothermometers

  11. Tree rings – isotopes of Oxygen

  12. Ice core sampling

  13. Check for understanding Which is surprising to climatologists – that the climate changes or the current rate of change? What is the name of the 100,000 year cycles of warming and cooling? How do climatologists study the ancient atmosphere? (name 4 ways) Why is a .7oC change significant?

  14. Climate and civilization • Human civilizations change when climate changes • 20,000 ybp (years before present) ice age: Bering strait freezes, people migrate to the Americas • 8,000-7,000 ybp – warming period Mesopotamia flourishing, Jericho established

  15. Mayan civilization – collapses suddenly 950 CE (common era – used to be called AD)Leif Erikson – 950 CE sails to Greenland

  16. Black Death in Europe – famine 1315-1317 – needed to import grain from ChinaLittle Ice age – 1550-1850 Irish Potato Famine

  17. Dust Bowl – 1930’s • Mild but persistent La Nina conditions coupled with changes of sea surface temperatures + poor farming practices

  18. Wrap it up – discuss with your neighbor: • Identify the evidence for and against anthropogenic climate change.

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