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Take a look at your I-clickers

Take a look at your I-clickers. 01A49D38 01B1DD6D 027BD2AB 0DACA607. The Last 2000 Years. Thousands of Years Before Present (log scale). Where does the Temperature data come from?. Tree Rings Lake Sediments and pollen Ice Cores (O-18) Coral (local water temp and O-18)

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Take a look at your I-clickers

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  1. Take a look at your I-clickers • 01A49D38 • 01B1DD6D • 027BD2AB • 0DACA607

  2. The Last 2000 Years

  3. Thousands of Years Before Present (log scale)

  4. Where does the Temperature data come from? • Tree Rings • Lake Sediments and pollen • Ice Cores (O-18) • Coral (local water temp and O-18) • Boreholes (local air temp) • Ocean Sediment O-18 (water temp) • REMEMBER! All temperatures are local!

  5. Tree Rings • In general, trees grow faster when it is milder and wetter. • So the size of the rings show the local climate • Since there are lots of trees we can get localized climate signals from lots of places • In some places we have records going back 12,400 years

  6. Complications • But…..trees respond a bit differently in different areas • Growth in cold regions depend largely on warm springs • In arid regions, water is the critical factor (duh) • CO2 is a serious complication since it stimulates growth

  7. Medieval Warm Period • The Medieval Warm Period (MWP) is generally thought to have occurred from about AD 950–1250 • It was probably cooler than now, but warm in comparison to ancient and later medieval times • The Vikings took advantage of ice-free seas to colonize Iceland and Greenland • Vineyards in the south of England were successful

  8. Vikings Fall of Rome Peak of the Roman Empire First Crusade Charlemagne Collapse of Mayan Civilization

  9. Knarr: TransAtlantic Cargo Ship Length 54 Ft Beam: 16 ft

  10. The Black Death The French Revolution The Industrial Revolution

  11. What effects short-term climate? • BIG volcanic eruptions • Sunspots • Climate Oscillations • El Nino • Pacific Decadal Oscillation • North Atlantic Oscillation

  12. Volcanoes • Eruptions push gases high into stratosphere • Sulfur dioxide combines with water → sulfuric acid • Tiny droplets of liquid → aerosols • Liquid sulfuric acid, type of aerosol, very reflective • Thin layer of aerosols reflect sunlight, cool Earth • Cooling lasts 1-2 years, until aerosols fall • 1815 – Tambora → “year without a summer” • Tropical eruptions usually more impact

  13. The Year Without a Summer • A volcanic winter event caused by the 1815 eruption of Mount Tambora, in the Dutch East Indies (Indonesia), the largest known eruption in over 1,300 years. • On 4 June 1816, frosts were reported in Connecticut • On 6 June 1816, snow fell in Albany, New York, and Dennysville, Maine. • Nearly 12 inches (30 cm) of snow was observed in Quebec City in early June, with consequent additional loss of crop. • In July and August, lake and river ice were observed as far south as Pennsylvania. • Cool temperatures and heavy rains resulted in failed harvests in Europe, food riots in England, France, Germany and Switzerland.

  14. The Year Without a Summer • Hungary experienced brown snow. Italy experienced something similar, with red snow falling throughout the year. • In China, unusually low temperatures in summer and fall devastated rice production in Yunnan province in the southwest, resulting in widespread famine. • In July 1816 "incessant rainfall" during that "wet, ungenial summer" forced Mary Shelley and their friends to stay indoors for much of their Swiss holiday. • They decided to have a contest to see who could write the scariest story, leading Shelley to write Frankenstein.

  15. The Year Without a Summer • High levels of ash in the atmosphere led to unusually spectacular sunsets during this period, a feature celebrated in the paintings of J. M. W. Turner.

  16. Sunspots

  17. Terracing dates back about 5,000 years….the only limiting factor is a source of water

  18. Historical Records of El Nino • This is pieced together from a lot of journal sources • Abundance of sea birds • Heavy rains and floods • Outbreaks of cholera and malaria • What else?

  19. Pacific Decadal Oscillation • Changes in sea-surface temp over N. Pacific • Produce variations in overlying pressure • Warm phase: • NW US warm & dry • SW US wetter • Cool phase: • NW US wet • SW US drought • Phase may last 2 decades

  20. North Atlantic Oscillation • Departure in pressure between Azores high & Icelandic low • High values: • Strong jet stream • Cold air restricted to northernmost regions • NW Europe wet • Low values: • Weak jet stream • Cold outbreaks in US • NW Europe dry

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