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Part IV: Historical Climate Changes Lecture 18: The Little Ice Age

Part IV: Historical Climate Changes Lecture 18: The Little Ice Age. (Chapter 15). Vikings invaded southwestern Greenland. Vikings abandoned Greenland. Frequency of sea ice intrusion along the coast of Iceland. MW: 1000-1300. LIA: 1400-1900. Canada arctic lichen.

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Part IV: Historical Climate Changes Lecture 18: The Little Ice Age

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  1. Part IV: Historical Climate ChangesLecture 18: The Little Ice Age (Chapter 15)

  2. Vikings invaded southwestern Greenland Vikings abandoned Greenland Frequency of sea ice intrusion along the coast of Iceland MW: 1000-1300 LIA: 1400-1900

  3. Canada arctic lichen Dead lichen due to snow expansion indicates the time of LIA

  4. Mountain glacier: Annual layer, δ18O, Dust content,

  5. MW LIA Ice core in Peruvian Andes

  6. Ice cores in four regions Temperature change, not uniform! Warming? Global? MW and LIA seems to be present in tropical mountain glaciers, but not obvious in Greenland and Antarctic ice sheets MW LIA

  7. Tasmanian tree rings MW? LIA? Not obvious in SH Unprecedented warming?

  8. Reconstructed NH temperature (hockey stick pattern) Global warming? MW? LIA?

  9. Longest Instrument record LIA? Global warming?

  10. Temperature stations, Urban heat island effect

  11. Global surface temperature

  12. 1910 Recession of the Grinnell Glacier “Glacier National Park” 1997 Source: D. Fagre, USGS, 2004

  13. Kilimanjaro ice extent (km2) ?

  14. Little Penck Glacier, Kilimanjaro

  15. Sea level rise 5cm upper ocean warming, 3 cm land ice melting, 2 cm Greenland ice melting

  16. Increased cloud cover Unclear warming or cooling effect because unknown high or low clouds

  17. Arctic clouds (warming or cooling?) Arctic sea ice

  18. The growing season lengthens in Alaska

  19. Tree Ring Width Obs. Trend Tree ring Obs. Tair Model P ~ R

  20. Global Greening Trend (FPAR: Fraction of Photosynthetically Active Radiation) Total CO2 Physiology Carbon fertilization Radiation Obs. >1980 Obs. – crops

  21. Decrease in snow cover

  22. Reduced Arctic sea ice cover and thickness !

  23. Global Lake Open/Close Date Lake Mendota

  24. Fundamental Questions on MW/LIA 1) Are these change regional or global? 2) Is it cause by orbital forcing of reduced summer insolation or millennial variability? 3) What caused the rapid warming since 1900 that terminates the LIA?

  25. Forcing mechanism for centennial and decadal variability • Solar forcing • Natural variability: PDO, NAO

  26. 11 year cycle: solar radiation and sunspots

  27. More solar radiation from faculae More Sunspots

  28. Sunspot history from telescopes

  29. Forcing mechanism for interannual variability • Volcanic forcing • Natural variability: ESNO Relation between ENSO and volcanic activity?

  30. Eruption of Mount Pinatobo in 1991 and global cooling

  31. (Tropical) Volcanic cooling

  32. End of Lecture 19

  33. Lecture 20: El Nino, La Nina and Southern Oscillation (Chapter 16)

  34. Change of Climate Variability Tropical Pacific SST

  35. El Nino and Southern Oscillation: ENSO

  36. http://iri.columbia.edu/climate/ENSO/currentinfo/SST_table.html#figurehttp://iri.columbia.edu/climate/ENSO/currentinfo/SST_table.html#figure

  37. Historical record of El Nino

  38. Corals and tropical ocean Annual layers made of CaCO3, take ocean water δ18O (a proxy of temperature, but also with salinity effect) LIA? El Nino

  39. Evolution of the last 21,000 yrs Deglaciation, but not smooth

  40. Change of Climate Variability Tropical Pacific SST

  41. 1935 Texas (Dustbowl) 1997 Kansas

  42. Global surface temperature

  43. North Africa Climate Change SAHEL RAINFALL SST decadal variability! Charney Charney ? S. Nicholson

  44. Climate Change: Global to Regional Perspective Global US Wisconsin Madison

  45. End of Lecture 20

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